Armelle Viard
email: viard@cyceron.fr

Béatrice Desgranges

Francis Eustache

Pascale Piolino
email: pascale.piolino@parisdescartes.fr

Factors affecting medial temporal lobe engagement for past and future episodic events: an ALE meta-analysis of neuroimaging studies

Keywords: autobiographical memory, episodic events, hippocampus, medial temporal lobe, neuroimaging

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questioned whether methodological choices could influence the laterality of activations, namely (1) the type of cue used (generic versus specific), (2) the type of task performed (recognition versus recall/imagine), (3) the nature of the information retrieved (episodic versus "strictly" episodic events) and (4) the age of participants. We consider "strictly" episodic events as events which are not only spatio-temporally unique and personal like episodic events, but are also associated with contextual and phenomenological details. These four factors were compared two-by-two, generating eight whole-brain statistical maps.

Results indicate that (1) specific cues tend to activate more the right anterior hippocampus compared to the use of generic cues, (2) recall/imagine tasks tend to recruit more the left posterior parahippocampal gyrus compared to recognition tasks, (3) (re/pre)experiencing strictly episodic events tends to activate more the bilateral posterior hippocampus compared to episodic events and (4) older subjects tend to activate more the right anterior hippocampus

Introduction

In its current definition, episodic memory is closely related to episodic autobiographical memory [START_REF] Wheeler | Toward a theory of episodic memory: the frontal lobes and autonoetic consciousness[END_REF](Wheeler et al., , 2004;;Wheeler 2000;Tulving, 2002Tulving, , 2005)). Autobiographical memory (AM) is composed of different types of self-representations, from general knowledge about oneself (semantic AM, also referred to as "personal semantics") to very specific personal events (episodic AM) [START_REF] Tulving | How many memory systems are there[END_REF][START_REF] Tulving | Priming of semantic autobiographical knowledge: a case study of retrograde amnesia[END_REF][START_REF] Conway | Sensory-perceptual episodic memory and its context: autobiographical memory[END_REF]. Episodic AM is characterized by a particular self-reflective mental state, termed autonoetic consciousness, which implies that the person recollects or imagines his/her personal events with a sense of (re/pre)experiencing, by mentally "travelling in time" whether in the past or in the future [START_REF] Wheeler | Toward a theory of episodic memory: the frontal lobes and autonoetic consciousness[END_REF][START_REF] Tulving | Episodic and common sense: how far apart?[END_REF]. A further distinction can be made between episodic and strictly episodic AMs [START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF][START_REF] Viard | Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire lifespan of aged adults[END_REF]for reviews, Moscovitch et al., 2005;[START_REF] Piolino | Episodic autobiographical memories over the course of time: cognitive, neuropsychological and neuroimaging findings[END_REF]. Strictly episodic events are not only spatio-temporally unique and personal like episodic events, but are also accompanied by subjective (re/pre)experiencing (autonoetic consciousness) associated with recall/imagination of phenomenological details, i.e., sensory, perceptual, cognitive, affective internal contextual details [START_REF] Moscovitch | Recovered consciousness: a hypothesis concerning modularity and episodic memory[END_REF][START_REF] Moscovitch | Theories of memory and consciousness[END_REF][START_REF] Tulving | Episodic and declarative memory: role of the hippocampus[END_REF][START_REF] Brewer | What is recollective memory?[END_REF][START_REF] Conway | The construction of autobiographical memories in the self-memory system[END_REF][START_REF] Conway | Sensory-perceptual episodic memory and its context: autobiographical memory[END_REF][START_REF] Conway | The self and autobiographical memory: Correspondence and coherence[END_REF][START_REF] Tulving | Episodic and common sense: how far apart?[END_REF].

Autobiographical investigations generally concern the retrieval of the personal past. They can be subdivided between those dealing with the more general aspects of AM (semantic AM), in which participants retrieve the general facts about a personal event without reexperiencing it (e.g., recall familiar self-relevant faces or places), and those which focus on the specific aspects of AM (episodic AM) in which participants have to consciously recollect a personal past event, in its original encoding context (e.g., recall a specific event, in a unique spatio-temporal context). Concerning episodic future thinking (Atance and O'Neil, 2001), studies have required participants to either imagine future specific events which are not necessarily going to happen [START_REF] Addis | Remembering the past and imagining the future: common and distinct neural substrates during event construction and elaboration[END_REF]Hassabis et al., 2007;[START_REF] D'argembeau | Neural correlates of envisioning emotional events in the near and far future[END_REF] or future specific events which are actually planned or are reasonably going to happen in the future (Viard et al., 2011a;Weiler et al., 2010a;[START_REF] Peters | Episodic future thinking reduces reward delay discounting through an enhancement of prefrontal-mediotemporal interactions[END_REF]Botzung et al., 2008a;[START_REF] Szpunar | Neural substrates of envisioning the future[END_REF][START_REF] Okuda | Thinking of the future and past: the roles of the frontal pole and the medial temporal lobes[END_REF].

Findings from neuroimaging studies in healthy adults have brought new insights on the cerebral organization of episodic events, completing findings from neuropsychology (for autobiographical memory: [START_REF] Rosenbaum | New views on old memories: reevaluating the role of the hippocampal complex[END_REF][START_REF] Rosenbaum | Amnesia as an impairment of detail generation and binding: evidence from personal, fictional, and semantic narratives in K[END_REF][START_REF] Andelman | Bilateral hippocampal lesion and a selective impairment of the ability for mental time travel[END_REF][START_REF] Spiers | Hippocampal amnesia[END_REF][START_REF] Piolino | Autobiographical memory and autonoetic consciousness: triple dissociation in neurodegenerative diseases[END_REF][START_REF] Eustache | In the course of time: a PET study of the cerebral substrates of autobiographical amnesia in Alzheimer's disease[END_REF][START_REF] St-Laurent | Determinants of autobiographical memory in patients with unilateral temporal lobe epilepsy or excisions[END_REF][START_REF] Noulhiane | Autobiographical memory after temporal lobe resection: neuropsychological and MRI volumetric findings[END_REF] for episodic future thinking: [START_REF] Tulving | How many memory systems are there[END_REF]Hassabis et al., 2007;[START_REF] Klein | Memory and temporal experience. The effects of episodic memory loss on an amnesic patient's ability to remember the past and imagine the future[END_REF].

Previous reviews have shown that episodic AM retrieval involves a circumscribed cerebral network comprising both anterior and posterior regions, including prefrontal and medial temporal cortices, medial parietal (posterior cingulate and retrosplenial cortices), posterior parietal (precuneus and temporo-parietal junction), occipital regions and the cerebellum [START_REF] Maguire | Neuroimaging studies of autobiographical event memory[END_REF][START_REF] Conway | Brain imaging autobiographical memory[END_REF][START_REF] Moscovitch | Functional neuroanatomy of remote episodic, semantic and spatial memory: a unified account based on multiple trace theory[END_REF][START_REF] Moscovitch | The cognitive neuroscience of remote episodic, semantic and spatial memory[END_REF][START_REF] Svoboda | The functional neuroanatomy of autobiographical memory: a meta-analysis[END_REF][START_REF] Cabeza | Functional neuroimaging of autobiographical memory[END_REF]. This neural pattern has striking similarities with the one recruited during episodic future thinking (for reviews, [START_REF] Buckner | Self-projection and the brain[END_REF][START_REF] Schacter | The cognitive neuroscience of constructive memory: remembering the past and imagining the future[END_REF]Hassabis andMaguire, 2007, 2009).

Neuroimaging studies of past remembering and future thinking have shown many consistencies, but some aspects remain unclear or obscure, especially concerning hippocampal and adjacent medial temporal lobe (MTL) laterality and antero-posterior activity. Within the MTL, the hippocampus is particularly important in episodic memory.

Concerning its laterality, results are discrepant: several episodic AM studies have shown preferentially left-sided hippocampal activations [START_REF] Maguire | Differential modulation of a common memory retrieval network revealed by positron emission tomography[END_REF][START_REF] Maguire | Patterns of hippocampal-cortical interaction dissociate temporal lobe memory subsystems[END_REF][START_REF] Maguire | Activity in prefrontal cortex, not hippocampus, varies parametrically with the increasing remoteness of memories[END_REF][START_REF] Markowitsch | Engagement of lateral and medial prefrontal areas in the ecphory of sad and happy autobiographical memories[END_REF][START_REF] Piefke | Differential remoteness and emotional tone modulate the neural correlates of autobiographical memory[END_REF][START_REF] Daselaar | The spatiotemporal dynamics of autobiographical memory: neural correlates of recall, emotional intensity, and reliving[END_REF][START_REF] Oddo | Specific role of medial prefrontal cortex in retrieving recent autobiographical memories: an fMRI study of young female subjects[END_REF][START_REF] Svoboda | The effects of rehearsal on the functional neuroanatomy of episodic autobiographical and semantic remembering: a functional magnetic resonance imaging study[END_REF]St Jacques et al., 2011a), while others have detected predominantly right hippocampal activations [START_REF] Fink | Cerebral representation of one's own past: neural networks involved in autobiographical memory[END_REF][START_REF] Okuda | Thinking of the future and past: the roles of the frontal pole and the medial temporal lobes[END_REF][START_REF] Steinvorth | Ecphory of autobiographical memories: an fMRI study of recent and remote memory retrieval[END_REF]. Furthermore, an increasing number of studies have shown bilateral hippocampal recruitment during episodic AM retrieval [START_REF] Ryan | Hippocampal complex and retrieval of recent and very remote autobiographical memories: evidence from functional magnetic resonance imaging in neurologically intact people[END_REF]Maguire and Frith, 2003a, b;[START_REF] Piolino | Re-experiencing old memories via hippocampus: a PET study of autobiographical memory[END_REF][START_REF] Piolino | Reliving lifelong episodic autobiographical memories via the hippocampus: A correlative resting PET study in healthy middle-aged subjects[END_REF][START_REF] Gilboa | Remembering our past: functional neuroanatomy of recollection of recent and very remote personal events[END_REF]Addis et al., 2004a;[START_REF] Cabeza | Brain activity during episodic retrieval of autobiographical and laboratory events: an fMRI study using a novel photo paradigm[END_REF][START_REF] Mayes | Recalling spatial information as a component of recently and remotely acquired episodic or semantic memories: an fMRI study[END_REF][START_REF] Greenberg | Co-activation of the amygdala, hippocampus and inferior frontal gyrus during autobiographical memory retrieval[END_REF][START_REF] Rekkas | Evidence that autobiographic memory retrieval does not become independent of the hippocampus: an fMRI study contrasting very recent with remote events[END_REF][START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF][START_REF] Viard | Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire lifespan of aged adults[END_REF][START_REF] Nadel | Autobiographical memory retrieval and hippocampal activation as a function of repetition and the passage of time[END_REF][START_REF] Mendelsohn | Subjective vs. documented reality: a case study of long-term real-life autobiographical memory[END_REF][START_REF] Trinkler | Neural bases of autobiographical support for episodic recollection of faces[END_REF][START_REF] Rabin | Common and unique neural correlates of autobiographical memory and theory of mind[END_REF][START_REF] Hoscheidt | Hippocampal activation during retrieval of spatial context from episodic and semantic memory[END_REF]. Concerning episodic future thinking, results are also inconsistent since some studies detect left hippocampal [START_REF] Addis | Remembering the past and imagining the future: common and distinct neural substrates during event construction and elaboration[END_REF](Addis et al., , 2008;;[START_REF] Spreng | Patterns of brain activity supporting autobiographical memory, prospection, and theory of mind, and their relationship to the default mode network[END_REF], right hippocampal [START_REF] Okuda | Thinking of the future and past: the roles of the frontal pole and the medial temporal lobes[END_REF]Weiler et al., 2010a;Addis et al., 2011a) or bilateral activation [START_REF] Abraham | Thinking about the future versus the past in personal and non-personal contexts[END_REF]Hassabis et al., 2007;[START_REF] Weiler | When the future becomes the past: Differences in brain activation patterns for episodic memory and episodic future thinking[END_REF][START_REF] Addis | Episodic simulation of future events is impaired in mild Alzheimer's disease[END_REF]Viard et al., 2011a).

Hypotheses have been formulated concerning the differential contribution of each hippocampus in episodic AM retrieval. It has been suggested that the left hippocampus is more involved in context-dependent episodic memory and is triggered by retrieval details (Addis et al., 2004a) or vividness of remote AMs [START_REF] Gilboa | Remembering our past: functional neuroanatomy of recollection of recent and very remote personal events[END_REF], whereas the right hippocampus is more linked to the emotional nature of AMs [START_REF] Fink | Cerebral representation of one's own past: neural networks involved in autobiographical memory[END_REF] or more engaged by spatial memory (for reviews, [START_REF] Burgess | The human hippocampus and spatial and episodic memory[END_REF][START_REF] Svoboda | The functional neuroanatomy of autobiographical memory: a meta-analysis[END_REF], sense of remembering and richness of mental visual imagery [START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF][START_REF] Viard | Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire lifespan of aged adults[END_REF]. Personal importance of AMs was shown to correlate with activation in the hippocampus bilaterally (Addis et al., 2004a). The age of the participants can also affect hippocampal laterality as several studies have shown greater right hippocampal activation in older compared to younger adults [START_REF] Maguire | Aging affects the engagement of the hippocampus during autobiographical memory retrieval[END_REF]St Jacques et al., in press). However, inconsistencies remain, for example, in several context-dependent episodic memory tasks which do not detect left-hippocampal activation, but right activation instead [START_REF] Okuda | Thinking of the future and past: the roles of the frontal pole and the medial temporal lobes[END_REF][START_REF] Steinvorth | Ecphory of autobiographical memories: an fMRI study of recent and remote memory retrieval[END_REF] or in tasks with a strong spatial component which do not recruit the right hippocampus [START_REF] Niki | An fMRI study on the time-limited role of the medial temporal lobe in long-term topographical autobiographic memory[END_REF]. A further point concerns studies reporting no hippocampal activations during personal episodic AM retrieval (see below; [START_REF] Andreasen | Remembering the past: two facets of episodic memory explored with positron emission tomography[END_REF][START_REF] Andreasen | The cerebellum plays a role in conscious episodic memory retrieval[END_REF][START_REF] Conway | A positron emission tomography (PET) study of autobiographical memory retrieval[END_REF][START_REF] Markowitsch | Right amygdalar and temporofrontal activation during autobiographic, but not fictitious memory retrieval[END_REF][START_REF] Nyberg | Brain imaging of human memory systems: between-systems similarities and within-system differences[END_REF][START_REF] Tsukiura | Time-dependent contribution of the hippocampal complex when remembering the past: a PET study[END_REF][START_REF] Graham | The neural basis of autobiographical and semantic memory: new evidence from three PET studies[END_REF][START_REF] Niki | An fMRI study on the time-limited role of the medial temporal lobe in long-term topographical autobiographic memory[END_REF][START_REF] Levine | The functional neuroanatomy of episodic and semantic autobiographical remembering: a prospective functional MRI study[END_REF][START_REF] Gardini | Left mediotemporal structures mediate the retrieval of episodic autobiographical mental images[END_REF]Denkova et al., 2006a;[START_REF] D'argembeau | The neural basis of personal goal processing when envisioning future events[END_REF].

Furthermore, the antero-posterior hippocampal differentiation has been shown to depend on a variety of different processes. The anterior hippocampus has been associated with processing environmental context [START_REF] Bannerman | Regional dissociations within the hippocampus-memory and anxiety[END_REF][START_REF] Kjelstrup | Finite scale of spatial representation in the hippocampus[END_REF], stimulus novelty [START_REF] Strange | Segregating the functions of human hippocampus[END_REF][START_REF] Daselaar | The medial temporal lobe distinguishes old from new independently of consciousness[END_REF][START_REF] Dudukovic | Goal-dependent modulation of declarative memory: neural correlates of temporal recency decisions and novelty detection[END_REF][START_REF] Doeller | Parallel striatal and hippocampal systems for landmarks and boundaries in spatial memory[END_REF][START_REF] Poppenk | Past experience modulates the neural mechanisms of episodic memory formation[END_REF], arousal, emotion, reward and goal proximity [START_REF] Moser | Functional differentiation in the hippocampus[END_REF][START_REF] Fanselow | Are the dorsal and ventral hippocampus functionally distinct structures?[END_REF][START_REF] Royer | Distinct representations and theta dynamics in dorsal and ventral hippocampus[END_REF]Viard et al., 2011b). The posterior hippocampus is thought to support spatial navigation [START_REF] O'keefe | The Hippocampus as a Cognitive Map[END_REF][START_REF] Burgess | The human hippocampus and spatial and episodic memory[END_REF][START_REF] Maguire | Knowing where and getting there: a human navigation network[END_REF][START_REF] Ekstrom | Cellular networks underlying human spatial navigation[END_REF][START_REF] Hartley | The well-worn route and the path less travelled: distinct neural bases of route following and wayfinding in humans[END_REF][START_REF] Moser | Functional differentiation in the hippocampus[END_REF][START_REF] Doeller | Parallel striatal and hippocampal systems for landmarks and boundaries in spatial memory[END_REF][START_REF] Moser | Place cells, grid cells, and the brain's spatial representation system[END_REF]. Various claims have been advanced regarding the locus of activation along the antero-posterior axis of the hippocampus during encoding versus retrieval. Its anterior portion would support episodic encoding [START_REF] Lepage | Hippocampal PET activations of memory encoding and retrieval: the HIPER model[END_REF][START_REF] Schacter | Medial temporal lobe activations in fMRI and PET studies of episodic encoding and retrieval[END_REF][START_REF] Spaniol | Event-related fMRI studies of episodic encoding and retrieval: meta-analyses using activation likelihood estimation[END_REF], while its posterior portion, and adjacent parahippocampal structures, would support episodic retrieval [START_REF] Spaniol | Event-related fMRI studies of episodic encoding and retrieval: meta-analyses using activation likelihood estimation[END_REF][START_REF] Lepage | Hippocampal PET activations of memory encoding and retrieval: the HIPER model[END_REF][START_REF] Greicius | Regional analysis of hippocampal activation during memory encoding and retrieval: fMRI study[END_REF][START_REF] Henson | Further dissociating the processes involved in recognition memory: An FMRI study[END_REF][START_REF] Ludowig | Intracranially recorded memory-related potentials reveal higher posterior than anterior hippocampal involvement in verbal encoding and retrieval[END_REF][START_REF] Schacter | Medial temporal lobe activations in fMRI and PET studies of episodic encoding and retrieval[END_REF].

A role of the parahippocampal gyrus in episodic AM [START_REF] Tsukiura | Time-dependent contribution of the hippocampal complex when remembering the past: a PET study[END_REF][START_REF] Okuda | Thinking of the future and past: the roles of the frontal pole and the medial temporal lobes[END_REF]Addis et al., 2004a;[START_REF] Levine | The functional neuroanatomy of episodic and semantic autobiographical remembering: a prospective functional MRI study[END_REF][START_REF] Greenberg | Co-activation of the amygdala, hippocampus and inferior frontal gyrus during autobiographical memory retrieval[END_REF][START_REF] Steinvorth | Ecphory of autobiographical memories: an fMRI study of recent and remote memory retrieval[END_REF][START_REF] Gardini | Left mediotemporal structures mediate the retrieval of episodic autobiographical mental images[END_REF]Denkova et al., 2006a, b;[START_REF] Burianova | Common and unique neural activations in autobiographical, episodic, and semantic retrieval[END_REF] and future thinking [START_REF] Okuda | Thinking of the future and past: the roles of the frontal pole and the medial temporal lobes[END_REF][START_REF] Szpunar | Neural substrates of envisioning the future[END_REF][START_REF] Szpunar | Contextual processing in episodic future thought[END_REF][START_REF] Addis | Remembering the past and imagining the future: common and distinct neural substrates during event construction and elaboration[END_REF]Addis et al., , 2008[START_REF] Addis | Episodic simulation of future events is impaired in mild Alzheimer's disease[END_REF]Addis et al., , 2011a;;[START_REF] Abraham | Thinking about the future versus the past in personal and non-personal contexts[END_REF]Botzung et al., 2008a;[START_REF] Spreng | Patterns of brain activity supporting autobiographical memory, prospection, and theory of mind, and their relationship to the default mode network[END_REF]Viard et al., 2011a) is well established, as well as its interaction with the hippocampus during autobiographical recognition [START_REF] Maguire | Patterns of hippocampal-cortical interaction dissociate temporal lobe memory subsystems[END_REF] or recall [START_REF] Greenberg | Co-activation of the amygdala, hippocampus and inferior frontal gyrus during autobiographical memory retrieval[END_REF][START_REF] Viard | Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire lifespan of aged adults[END_REF]. Its role according to its laterality is not yet clear, although some studies suggest that the right parahippocampal gyrus is implicated in the retrieval of topographical or spatial episodic AMs and could be related to the recruitment of posterior visual areas [START_REF] Tsukiura | Time-dependent contribution of the hippocampal complex when remembering the past: a PET study[END_REF][START_REF] Viard | Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire lifespan of aged adults[END_REF]. Its specialization along an antero-posterior axis seems more evident, the anterior part involved in item information and the posterior part processing context information [START_REF] Diana | Imaging recollection and familiarity in the medial temporal lobe: a three-component model[END_REF][START_REF] Davachi | Item, context and relational episodic encoding in humans[END_REF][START_REF] Slotnick | Does the hippocampus mediate objective binding or subjective remembering?[END_REF].

Another region within the MTL is the amygdala which has a well documented role in processing of emotional AMs [START_REF] Greenberg | Co-activation of the amygdala, hippocampus and inferior frontal gyrus during autobiographical memory retrieval[END_REF][START_REF] Hoscheidt | Hippocampal activation during retrieval of spatial context from episodic and semantic memory[END_REF][START_REF] Nadel | Autobiographical memory retrieval and hippocampal activation as a function of repetition and the passage of time[END_REF][START_REF] Daselaar | The spatiotemporal dynamics of autobiographical memory: neural correlates of recall, emotional intensity, and reliving[END_REF][START_REF] Markowitsch | Right amygdalar and temporofrontal activation during autobiographic, but not fictitious memory retrieval[END_REF][START_REF] Markowitsch | Engagement of lateral and medial prefrontal areas in the ecphory of sad and happy autobiographical memories[END_REF][START_REF] Fink | Cerebral representation of one's own past: neural networks involved in autobiographical memory[END_REF][START_REF] Viard | Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire lifespan of aged adults[END_REF] and future events [START_REF] Sharot | Neural mechanisms mediating optimism bias[END_REF][START_REF] Addis | Episodic simulation of future events is impaired in mild Alzheimer's disease[END_REF]. Episodic AMs tend to be highly emotional due to their personal involvement which, in most cases, facilitates their accessibility at retrieval [START_REF] Talarico | Confidence, not consistency, characterizes flashbulb memories[END_REF]. Emotional intensity affects the perceptual and phenomenological properties of AMs, such as its vividness, level of detail and the degree to which the memory is relived [START_REF] Talarico | Emotional intensity predicts autobiographical memory experience[END_REF] for reviews, see [START_REF] Phelps | Human emotion and memory: interactions of the amygdala and hippocampal complex[END_REF][START_REF] Labar | Cognitive neuroscience of emotional memory[END_REF]. Functional interactions have been detected between the amygdala and the hippocampus during encoding [START_REF] Hamann | Amygdala activity related to enhanced memory for pleasant and aversive stimuli[END_REF][START_REF] Dolcos | Interaction between the amygdala and the medial temporal lobe memory system predicts better memory for emotional events[END_REF], as well as during retrieval [START_REF] Dolcos | Remembering one year later: role of the amygdala and the medial temporal lobe memory system in retrieving emotional memories[END_REF][START_REF] Viard | Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire lifespan of aged adults[END_REF], especially if recall is accompanied by a sense of recollection [START_REF] Talarico | Emotional intensity predicts autobiographical memory experience[END_REF][START_REF] Ochsner | Are affective events richly recollected or simply familiar? The experience and process of recognizing feelings past[END_REF][START_REF] Sharot | How emotion enhances the feeling of remembering[END_REF]. Concerning amygdalar laterality, results are inconsistent, some showing preferentially left [START_REF] Dolan | Dissociable temporal lobe activations during emotional episodic memory retrieval[END_REF] or right activation [START_REF] Fink | Cerebral representation of one's own past: neural networks involved in autobiographical memory[END_REF] during AM retrieval. Inconsistencies regarding the influence of emotional valence on amygdalar laterality have also emerged [START_REF] Markowitsch | Engagement of lateral and medial prefrontal areas in the ecphory of sad and happy autobiographical memories[END_REF][START_REF] Piefke | Differential remoteness and emotional tone modulate the neural correlates of autobiographical memory[END_REF][START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF].

The contradictory findings concerning MTL laterality and antero-posterior activity could arise, at least in part, from the use of various experimental procedures which do not tap the same aspects of (re/pre)experiencing and could, hence, limit the extent of previous findings.

Methodological choices vary across studies and encompass differences in time frames, trial designs (segregation of search and elaboration phases), method to elicit memory (generic cue versus personal cues from a pre-scan interview; [START_REF] Addis | Remembering the past and imagining the future: common and distinct neural substrates during event construction and elaboration[END_REF][START_REF] Addis | Episodic simulation of future events is impaired in mild Alzheimer's disease[END_REF][START_REF] Rabin | Common and unique neural correlates of autobiographical memory and theory of mind[END_REF], re-encoding, number of lifetime periods (or memory remoteness), number of memories recollected, true/false recognition versus recall tasks (St Jacques et al., in press;[START_REF] Oddo | Specific role of medial prefrontal cortex in retrieving recent autobiographical memories: an fMRI study of young female subjects[END_REF][START_REF] Piefke | Differential remoteness and emotional tone modulate the neural correlates of autobiographical memory[END_REF], age of subjects [START_REF] Maguire | Aging affects the engagement of the hippocampus during autobiographical memory retrieval[END_REF][START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF]. A previous review, centered on the prefrontal cortex, suggested that laterality effects on neural activation patterns associated to encoding and retrieval of laboratory based episodic memory depend on stimulus characteristics (type of material, modality of presentation), complexity of stimulus material, information to be retrieved and task demands, rather than on functional hemispheric specializations [START_REF] Lee | Episodic memory meets working memory in the frontal lobe: functional neuroimaging studies of encoding and retrieval[END_REF]. Up to date, no meta-analysis has yet attempted to tackle this issue within the MTL to determine the impact of methodological choices on hippocampal and adjacent MTL activations for past and future episodic events. Here, we chose to focus on four factors which can be identified in all studies: the type of cue used (generic versus specific), type of task performed (recognition versus recall/imagine), nature of the information retrieved (episodic versus strictly episodic) and age of participants (younger versus older).

Indeed, studies vary immensely in terms of the type of cue (generic or specific) used to elicit (re/pre)experiencing. The cue-word technique is often used in which participants are required to recall/imagine a personal event related to an impersonal cue word (e.g., flower), phrase or picture (Table 1). Cues are identical for all participants and might not elicit the most personally significant events which may influence hippocampal activation. Specific (personal) cues provide more direct access to episodic information, while generic (impersonal) cues do not and need more elaborate cue-specification and further retrieval attempts. Studies also vary with respect to the type of task (recognition or recall/imagine) performed in the scanner. In recognition verification tasks, participants must indicate if they recognize a cued event, responding by yes or no, without full (re/pre)experiencing. This procedure seems unlikely to engage participants to recollect/imagine richly detailed events, compared to recall/imagine tasks (Table 1). Recognition tasks can be executed by accessing the general levels of autobiographical knowledge without retrieving the episodic details. The nature of the information retrieved (semantic, episodic or strictly episodic) may also influence (re/pre)experiencing. In some studies, participants are asked to retrieve information derived from their "personal semantics", while in others, they must recall a spatio-temporally unique and specific event. Stimuli belonging to the subjects' personal semantics may not incite participants to recall specific context-rich personal events (i.e., names of acquaintances, familiar faces, repeated events, topographical recall of personal routes or places visited). On the contrary, they may retrieve the general facts about an event in the absence of recollection of episodic details. In a growing number of studies, participants are incited to retrieve "strictly episodic" events by recollecting events unique in time and place, accompanied by subjective (re/pre)experiencing and phenomenological qualities, such as emotion, details, visual imagery, vividness, personal significance and autonoetic consciousness (Table 1). Similarly, for future thinking, imagining a fictitious future event which is not necessarily going to happen might not require the same personal and emotional involvement, and phenomenological experiencing, than future events which are planned and will happen in the participants' lives. Finally, the age of participants has been previously shown to affect hippocampal activation with older adults recruiting the right hippocampus, in addition to its left counterpart generally detected in young adults [START_REF] Maguire | Aging affects the engagement of the hippocampus during autobiographical memory retrieval[END_REF]St Jacques et al., in press;[START_REF] Ryan | Hippocampal complex and retrieval of recent and very remote autobiographical memories: evidence from functional magnetic resonance imaging in neurologically intact people[END_REF][START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF][START_REF] Nadel | Autobiographical memory retrieval and hippocampal activation as a function of repetition and the passage of time[END_REF][START_REF] Gilboa | Remembering our past: functional neuroanatomy of recollection of recent and very remote personal events[END_REF]. [START_REF] Maguire | Aging affects the engagement of the hippocampus during autobiographical memory retrieval[END_REF] suggested that a hemispheric asymmetry reduction in older adults could account for the bilateral involvement of the hippocampus, as proposed in prefrontal areas (HAROLD model, Cabeza 2002).

The variety of experimental designs used to study past and future episodic events and, consequently, the disparate results obtained, make it difficult to compare studies, particularly on the question of hippocampal and extra-hippocampal MTL laterality and antero-posterior activity. Growing evidence suggests that activity in this region may be modulated by factors such as the type of cue used [START_REF] Addis | Remembering the past and imagining the future: common and distinct neural substrates during event construction and elaboration[END_REF][START_REF] Addis | Episodic simulation of future events is impaired in mild Alzheimer's disease[END_REF]Oddo et al., 2008;[START_REF] Rabin | Common and unique neural correlates of autobiographical memory and theory of mind[END_REF]St Jacques et al., in press), the type of task (St Jacques et al., in press;[START_REF] Piolino | Re-experiencing old memories via hippocampus: a PET study of autobiographical memory[END_REF][START_REF] Piefke | Differential remoteness and emotional tone modulate the neural correlates of autobiographical memory[END_REF], the nature of the information required [START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF](Viard et al., , 2011;;[START_REF] Piolino | Re-experiencing old memories via hippocampus: a PET study of autobiographical memory[END_REF][START_REF] Piolino | Reliving lifelong episodic autobiographical memories via the hippocampus: A correlative resting PET study in healthy middle-aged subjects[END_REF] or the age of participants (Maguire et al., 2003a;St Jacques et al., in press;[START_REF] Ryan | Hippocampal complex and retrieval of recent and very remote autobiographical memories: evidence from functional magnetic resonance imaging in neurologically intact people[END_REF][START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF][START_REF] Nadel | Autobiographical memory retrieval and hippocampal activation as a function of repetition and the passage of time[END_REF][START_REF] Gilboa | Remembering our past: functional neuroanatomy of recollection of recent and very remote personal events[END_REF]. The present metaanalysis is an extensive investigation of hippocampal and adjacent MTL activations reported in neuroimaging studies of past remembering and future thinking. Hence, studies on episodic AM and future thinking were included. Its originality compared to other recent meta-analyses on episodic memory [START_REF] Svoboda | The functional neuroanatomy of autobiographical memory: a meta-analysis[END_REF][START_REF] Spreng | The common neural basis of autobiographical memory, prospection, navigation, theory of mind, and the default mode: a quantitative meta-analysis[END_REF][START_REF] Mcdermott | Laboratory-based and autobiographical retrieval tasks differ substantially in their neural substrates[END_REF]Kim et al., in press;[START_REF] Gilboa | Autobiographical and episodic memory--one and the same? Evidence from prefrontal activation in neuroimaging studies[END_REF] lies in the way it aims at identifying which methodological factors are more likely to influence hippocampal and extra-hippocampal MTL laterality and antero-posterior activity, using a meta-analysis centred on MTL coordinates.

Concerning hippocampal laterality, we predicted that specific cues (versus generic cues), recall/imagine tasks (versus recognition tasks) tasks and (re/pre)experiencing strictly episodic events (versus episodic events) would elicit greater bilateral hippocampal engagement, since these factors tend to favour (re/pre)experiencing accompanied by contextual and phenomenological details. For the same reasons, we predicted that specific cues, recall/imagine tasks and (re/pre)experiencing strictly episodic events would elicit greater anterior and posterior hippocampal recruitment. Concerning the age of participants, we predicted that older adults would elicit greater right hippocampal activation compared to younger subjects, based on current hypotheses of hemispheric reduction due to age (HAROLD, Cabeza, 2002). Based on models on the functional segregation of the parahippocampal gyrus [START_REF] Graham | Going beyond LTM in the MTL: a synthesis of neuropsychological and neuroimaging findings on the role of the medial temporal lobe in memory and perception[END_REF], we predicted that specific cues, recall/imagine tasks and (re/pre)experiencing strictly episodic events would elicit greater posterior parahippocampal activation. Given the role of the amygdala in the retrieval of rich emotional AMs, we predicted that strictly episodic events would elicit greater amygdalar activation compared to episodic events.

Methods

Study selection

We conducted multiple literature searches using Pubmed to find all PET and fMRI studies published before October 2011 whose titles, keywords, or abstracts included the terms "autobiographical memory", "episodic memory", "everyday memory", "personal events", "future thinking", "episodic simulation", "episodic future thinking", "future envisioning", "imagining", "self-projection", "mental time travel", "fMRI" or "PET". We identified additional relevant studies by searching through reference lists of these articles not identified by the online database query. These search results were filtered to include only studies that (i) performed voxel-wise contrasts (i.e., whole-brain or within a region-of-interest) (ii) used univariate or multivariate analysis approaches with uniform significance and cluster size thresholds applied throughout the brain, and (iii) reported standard-space stereotactic coordinates within the hippocampus, parahippocampal gyrus or amygdala for at least one of the contrasts of interest (see below). We selected contrasts comparing the episodic event condition (past or future) to a control condition. Twenty-four studies did not fit inclusion criteria, either because they did not provide MTL stereotactic coordinates (7 studies), did not detect MTL activation (4 studies) or did not detect MTL activation for the contrast of interest (i.e., episodic event versus control conditions; 2 studies), used electroencephalography (3 studies) or reported contrasts inappropriate to the present analyses (8 studies), e.g. comparisons of two personal event conditions (remote vs. recent, past vs. future, positive vs. negative events) or comparisons including semantic conditions compared to control (all conditions including semantic condition vs. control). A reason which may explain the failure to detect MTL activation in 4 studies may be the use of PET [START_REF] Andreasen | Remembering the past: two facets of episodic memory explored with positron emission tomography[END_REF][START_REF] Andreasen | The cerebellum plays a role in conscious episodic memory retrieval[END_REF][START_REF] Conway | A positron emission tomography (PET) study of autobiographical memory retrieval[END_REF][START_REF] Nyberg | Brain imaging of human memory systems: between-systems similarities and within-system differences[END_REF], an imaging technique which is less sensitive than fMRI to detect subtle hippocampal activations. Another reason could be that methods to analyze data have improved in recent neuroimaging studies (e.g., regions-of-interest method), enabling finer and more accurate explorations of particular regions, such as the hippocampus.

We excluded data from patients and children. Coordinates were classified as belonging to the MTL based on how the authors of the original articles classified the regions. With this approach, 269 MTL foci showing a greater activation for the episodic event condition (past or future) compared to baseline were obtained from 58 studies, involving 866 participants. Table 1 lists the number of participants, contrast and number of foci for each study included and Table 2 lists the studies which did not fit the inclusion criterion and reason for exclusion.

Contrast of interest

Separate ALE analyses [START_REF] Turkeltaub | Meta-analysis of the functional neuroanatomy of single-word reading: Method and validation[END_REF] were conducted for each contrast listed below. The ALE approach conceptualizes activation foci not as single points but as probability distributions surrounding each reported peak coordinate. Across studies, these probability distributions are summed, and the result is a whole-brain map in which each voxel represents the activation likelihood within the literature. To test our predictions described in the introduction, we examined four types of contrasts.

Generic vs. specific cues

To elicit past or future (re/pre)experiencing, participants are prompted to evoke personal past or future events upon (auditory or visual) presentation of cues (e.g., words, sentences, pictures). Different types of cues have been used, either generic (i.e., non-personal) or specific (i.e., personal). Generic cues are single words, impersonal phrases or pictures, usually derived from the cue-word technique, similar to the Crovitz technique [START_REF] Crovitz | Frequency of episodic memories as function of their age[END_REF], or from prior pilot studies. Specific cues are unique to each participant and strongly associated with the to-be-retrieved memories, individually constructed, inciting subjects to remember specific personal past events or envision specific future events. Two ALE comparisons were computed, one contrasting studies using generic cues compared with those using specific cues and the reverse.

Recognition vs. recall/imagine tasks

After presentation of a cue, participants are asked to either recognize the information by providing a yes/no response or to recall (i.e., re-experience) or imagine (i.e., pre-experience) the personal past or future event, respectively. Studies were classified as using a recognition task if participants were required to produce a veridical judgement upon cue presentation.

Studies were classified as using a cued recall or imagination task if participants were asked to retrieve or imagine an event with full (re/pre)experiencing upon cue presentation. Two ALE comparisons were computed, one contrasting studies using a recognition task compared with those using a recall/imagine task and the reverse.

Episodic vs. strictly episodic events

Studies were classified as either episodic if participants were asked to recall or imagine a personal event, unique in time and place or as strictly episodic if participants were required to recall or imagine a personal event, unique in time and place, with at least one of the following phenomenological qualities: emotion, details, visual imagery, vividness, personal significance and/or autonoetic consciousness. The strictly episodic categorization takes into account not only the specificity of the personal events that are retrieved (uniqueness, spatiotemporal location, details), but also the subjective experience of (re/pre)experiencing [START_REF] Moscovitch | Recovered consciousness: a hypothesis concerning modularity and episodic memory[END_REF][START_REF] Moscovitch | Theories of memory and consciousness[END_REF][START_REF] Tulving | Episodic and declarative memory: role of the hippocampus[END_REF]. Two ALE comparisons were computed, one contrasting studies requiring retieval/imagination of episodic compared to strictly episodic events and the reverse.

Younger vs. older participants

Studies were classified according to the age of the participants (age range: young = 15-42.4; middle-aged and aged = 50.75-77). Data from middle-aged and aged participants were grouped to obtain better statistical power. Two ALE comparisons were computed, one contrasting young compared to old subjects and the reverse.

ALE meta-analysis

Fifty-eight studies comprising a total of 866 subjects reported coordinates falling within the MTL when comparing the episodic event condition to baseline. Eight ALE analyses were computed [START_REF] Turkeltaub | Meta-analysis of the functional neuroanatomy of single-word reading: Method and validation[END_REF] for the contrasts of interest listed above. Because a large majority of the studies included in the meta-analysis (40/58 studies) reported their results in Talairach space, results were reported in this space, as other meta-analyses in the field [START_REF] Spreng | The common neural basis of autobiographical memory, prospection, navigation, theory of mind, and the default mode: a quantitative meta-analysis[END_REF][START_REF] Spaniol | Event-related fMRI studies of episodic encoding and retrieval: meta-analyses using activation likelihood estimation[END_REF]Kim et al., in press). Activation coordinates from studies using the standard space of the Montreal Neurological Institute (MNI) were converted to Talairach space [START_REF] Talairach | A co-planar stereotaxic atlas of the human brain[END_REF] using the Brett transform [START_REF] Brett | Using the Talairach atlas with the MNI template[END_REF]. Each activation peak was classified as left or right, according to the x coordinate. For the distinction between the anterior and posterior portions of the hippocampus, the division of y=-22 in Talairach space was chosen based on previous studies; [START_REF] Preston | Hippocampal contribution to the novel use of relational information in declarative memory[END_REF]Addis et al., 2008;[START_REF] Henson | A mini-review of fMRI studies of human medial temporal lobe activity associated with recognition memory[END_REF].

Meta-analyses were carried out using the revised version of ALE (ALE 2.1; [START_REF] Eickhoff | Coordinate-based activation likelihood estimation meta-analysis of neuroimaging data: a random-effects approach based on empirical estimates of spatial uncertainty[END_REF]. The algorithm aims at identifying areas showing a statistical convergence of reported activations across different experiments. The applied algorithm weights the betweensubject variance by the number of examined subjects per study. It could be argued that the contribution an experiment makes to an ALE map is dependent on the number of foci it reports. Yet, [START_REF] Turkeltaub | Minimizing within-experiment and within-group effects in Activation Likelihood Estimation meta-analyses[END_REF] show that these within-experiment effects only account for 2-3% of cumulative ALE values and removing them has little impact on thresholded ALE maps. Differences between conditions were tested by first performing an ALE analysis separately for each condition and computing the voxel-wise difference between the ensuing ALE maps. The resulting ALE maps were thresholded using 5000 permutations, controlling the false discovery rate (FDR) at p<0.05, with a minimum cluster volume of 100mm 3 . Thresholded ALE maps were overlaid onto the "colinbrain" Talairach template [START_REF] Kochunov | An optimized individual target brain in the Talairach coordinate system[END_REF] see Figure 1).

Results

Generic vs. specific cues

The resulting ALE map for paradigms using generic rather than specific cues is presented on Table 3 and Figure 1. MTL regions which are significantly associated with greater activity for paradigms using generic compared to specific cues are the left (BA 30) and right (BA 36) posterior parahippocampal gyri.

The resulting ALE map for paradigms using specific compared to generic cues is presented on Table 3 andFigure 1. The right anterior hippocampus showed significantly greater activity for paradigms using specific compared to generic cues.

Recognition vs. recall/imagine tasks

The resulting ALE map for paradigms using recognition rather than recall/imagine tasks is presented on Table 4 and Figure 1. The right (BAs 34, 28) and left (BAs 28, 34) anterior parahippocampal gyri and bilateral amygdala showed significantly greater activity for recognition compared to recall/imagine tasks.

The resulting ALE map for paradigms using recall/imagine compared to recognition tasks is depicted on Table 4 and Figure 1. The left posterior parahippocamapl gyrus (BA 30) showed significantly greater activity for recall/imagine compared to recognition tasks. It is important to note however that given the small number of studies classified as "recognition", these results must be interpreted with caution.

Episodic vs. strictly episodic events

The resulting ALE map when thinking about episodic rather than strictly episodic events is depicted on Table 5 and Figure 1. MTL regions significantly associated with greater activity for episodic compared to strictly episodic events are the left anterior parahippocampal gyrus (BA 28) and left amygdala.

The resulting ALE map when thinking about strictly episodic compared to episodic events is presented on Table 5 and Figure 1. The bilateral posterior hippocampus showed significantly greater activity for strictly episodic compared to episodic events.

To determine if the specific combination of strictly episodic events and specific cues was associated with greater hippocampal activation, we performed a further ALE analysis which compared strictly episodic to episodic (re/pre)experiencing triggered exclusively by specific cues (i.e. "episodic events and specific cues" vs. "strictly episodic events and specific cues").

Results, depicted on Table 6, show that specific cues associated to strictly episodic events elicit greater activity within the left posterior hippocampus compared to specific cues associated to episodic events. The reverse contrast reveals no greater activation for specific cues associated to episodic events compared to specific cues associated to strictly episodic events.

Younger vs. older participants

Results depicted on Table 7 show significantly greater activation in older subjects in the right anterior hippocampus, right anterior (BA 35) and bilateral posterior (BAs 27, 36) parahippocampal gyri, and left amygdala compared to the younger group. The reverse contrast revealed no greater activation for younger compared to older subjects.

Discussion

The principal aim of this meta-analysis was to focus on functional neuroimaging studies of past remembering and future thinking depicting activations in the MTL (hippocampus, parahippocampal gyrus and amygdala) and determine the influence of methodological factors on MTL laterality and antero-posterior activation. The meta-analysis, including 58 studies, showed that the type of cue used (generic versus specific), type of task performed (recognition versus recall/imagine), nature of the information retrieved (episodic versus strictly episodic) and the age of participants are important factors which influence MTL laterality and antero-posterior activation when thinking about past or future episodic events.

We will first focus our discussion on the role of the hippocampus in past and future episodic events and the effect of the different methodological factors on its laterality and anteroposterior activity. Then, we will concentrate on the additional roles of extra-hippocampal MTL regions.

Contribution of the hippocampus to past and future episodic events

Substantial evidence has shown that the hippocampus is crucial for episodic memory, in particular when (re/pre)experiencing is accompanied by the autonoetic consciousness of the contextual episode [START_REF] Eldridge | Remembering episodes: a selective role for the hippocampus during retrieval[END_REF][START_REF] Maguire | Activity in prefrontal cortex, not hippocampus, varies parametrically with the increasing remoteness of memories[END_REF][START_REF] Moscovitch | Material-specific deficits in "remembering" in patients with unilateral temporal lobe epilepsy and excisions[END_REF]. Differential roles have been attributed to the right and left hippocampi in episodic memory. Results from the meta-analysis show that the laterality of hippocampal activation may also depend on the methodology used to elicit past and future (re/pre)experiencing.

Bilateral hippocampus

Concordant with our predictions, ALE results show that (re/pre)experiencing strictly episodic events lead to greater activity in the bilateral hippocampus compared to episodic events. Strictly episodic events are not only spatio-temporally unique and personal like episodic events, but are also accompanied by the subjective experience of (re/pre)experiencing [START_REF] Moscovitch | Recovered consciousness: a hypothesis concerning modularity and episodic memory[END_REF][START_REF] Moscovitch | Theories of memory and consciousness[END_REF][START_REF] Tulving | Episodic and declarative memory: role of the hippocampus[END_REF], associated with recall/imagination of contextual and phenomenological details (i.e., sensory, perceptual, cognitive, affective internal contextual details). Bilateral hippocampal activation has been previously attributed to retrieval of specific AMs rich on recollective qualities (e.g., level of detail, emotionality, personal significance, (re/pre)experiencing, vividness; [START_REF] Ryan | Hippocampal complex and retrieval of recent and very remote autobiographical memories: evidence from functional magnetic resonance imaging in neurologically intact people[END_REF][START_REF] Okuda | Thinking of the future and past: the roles of the frontal pole and the medial temporal lobes[END_REF][START_REF] Piefke | Differential remoteness and emotional tone modulate the neural correlates of autobiographical memory[END_REF][START_REF] Graham | The neural basis of autobiographical and semantic memory: new evidence from three PET studies[END_REF]Addis et al., 2004a;[START_REF] Gilboa | Remembering our past: functional neuroanatomy of recollection of recent and very remote personal events[END_REF][START_REF] Mayes | Recalling spatial information as a component of recently and remotely acquired episodic or semantic memories: an fMRI study[END_REF][START_REF] Greenberg | Co-activation of the amygdala, hippocampus and inferior frontal gyrus during autobiographical memory retrieval[END_REF][START_REF] Piolino | Re-experiencing old memories via hippocampus: a PET study of autobiographical memory[END_REF][START_REF] Steinvorth | Ecphory of autobiographical memories: an fMRI study of recent and remote memory retrieval[END_REF][START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF][START_REF] Piolino | Reliving lifelong episodic autobiographical memories via the hippocampus: A correlative resting PET study in healthy middle-aged subjects[END_REF][START_REF] Abraham | Thinking about the future versus the past in personal and non-personal contexts[END_REF]St Jacques et al., in press).

Bilateral hippocampal activation has also been linked to imagination of specific future events (Viard et al., 2011a;[START_REF] Weiler | When the future becomes the past: Differences in brain activation patterns for episodic memory and episodic future thinking[END_REF]Hassabis and Maguire, 2007) and phenomenological characteristics (e.g., richness of details, temporal distance, emotional valence) were shown to affect activation patterns of future events (Addis and Schacter, 2008;Addis et al., 2008;[START_REF] D'argembeau | Neural correlates of envisioning emotional events in the near and far future[END_REF]. It is plausible that bilateral hippocampal activation is detected for strictly episodic events because they lead to more intense (re/pre)experiencing [START_REF] Eldridge | Remembering episodes: a selective role for the hippocampus during retrieval[END_REF][START_REF] Yonelinas | Hippocampal, parahippocampal and occipital-temporal contributions to associative and item recognition memory: an fMRI study[END_REF][START_REF] Yonelinas | Components of episodic memory: the contribution of recollection and familiarity[END_REF], binding together numerous contextual and phenomenological characteristics, compared to episodic events. This relational property may be necessary to construct coherent scenes of past and future (Hassabis et al., 2007;Addis et al., 2007;[START_REF] Spreng | Patterns of brain activity supporting autobiographical memory, prospection, and theory of mind, and their relationship to the default mode network[END_REF]Viard et al., 2011a).

Left hippocampus

Previous literature has attributed different roles to the left and right hippocampi. ALE results show that the strictly episodic nature of memory/imagination elicits greater activity in the left hippocampus (compared to standard episodic memory/imagination), especially when (re/pre)experiencing is triggered by specific cues. The left hippocampus seems specifically associated with the retrieval of detailed strictly episodic events [START_REF] Gilboa | Remembering our past: functional neuroanatomy of recollection of recent and very remote personal events[END_REF]Addis et al., 2004a) and is modulated by phenomenological quality [START_REF] Gilboa | Remembering our past: functional neuroanatomy of recollection of recent and very remote personal events[END_REF][START_REF] Rabin | Common and unique neural correlates of autobiographical memory and theory of mind[END_REF]Addis et al., 2008). The left hippocampus has a role in time-specific memory and personal experience [START_REF] Maguire | Differential modulation of a common memory retrieval network revealed by positron emission tomography[END_REF] and self-projection of one's self compared to others (St Jacques et al., 2011a). Its role has also been highlighted to facilitate general coherence of an episode or scene [START_REF] Rabin | Common and unique neural correlates of autobiographical memory and theory of mind[END_REF]Hassabis and Maguire, 2007).

There is an overlap for episodic past and future event construction in the left hippocampus [START_REF] Addis | Remembering the past and imagining the future: common and distinct neural substrates during event construction and elaboration[END_REF] and it remains online during elaboration suggesting it might have a role in generating complex coherent scenes [START_REF] St Jacques | Dynamic neural networks supporting memory retrieval[END_REF]. The greater left hippocampal involvement may be explained by the generation of more complex scenes for strictly episodic compared to episodic events. This effect appears to be exacerbated when (re/pre)experiencing is triggered by specific cues probably because they prompt recall/imagination more directly, unlike generic cues (see below).

Right hippocampus

Greater right hippocampal activation was detected with the use of specific (i.e., personal) compared to generic (i.e., impersonal nouns or words) cues, regardless of the strict nature of events. Specific cues provide more direct access to episodic information [START_REF] Addis | Episodic simulation of future events is impaired in mild Alzheimer's disease[END_REF], while generic cues require more elaborate cue-specification and further retrieval attempts [START_REF] Addis | Remembering the past and imagining the future: common and distinct neural substrates during event construction and elaboration[END_REF]. During construction, generic cues do not result in hippocampal activation, while specific cues directly evoke recollection of personal events leading to MTL activation [START_REF] Addis | Remembering the past and imagining the future: common and distinct neural substrates during event construction and elaboration[END_REF][START_REF] Rabin | Common and unique neural correlates of autobiographical memory and theory of mind[END_REF][START_REF] Conway | Neurophysiological correlates of memory for experienced and imagined events[END_REF]. Right activation may reflect emotional properties [START_REF] Fink | Cerebral representation of one's own past: neural networks involved in autobiographical memory[END_REF], self-perspective or retrieval of spatial details (see below). Right hippocampal activation may also depend on the time allotted for retrieval [START_REF] Graham | The neural basis of autobiographical and semantic memory: new evidence from three PET studies[END_REF][START_REF] Piolino | Re-experiencing old memories via hippocampus: a PET study of autobiographical memory[END_REF] which can be circumscribed by the use of specific cues which directly trigger a personal event.

It is now well established that the right hippocampus plays a role in spatial episodic representation [START_REF] O'keefe | The Hippocampus as a Cognitive Map[END_REF]Hirshhorn et al., in press;for review, Burgess et al., 2002), notably in autobiographical recall (Maguire and Frith, 2003a, b;[START_REF] Gilboa | Remembering our past: functional neuroanatomy of recollection of recent and very remote personal events[END_REF][START_REF] Piolino | Re-experiencing old memories via hippocampus: a PET study of autobiographical memory[END_REF][START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF]. The right hippocampus may be driven by initial spatial or relational processing of complex visual scenes (Hassabis et al., 2007;[START_REF] Binder | A comparison of two FMRI protocols for eliciting hippocampal activation[END_REF][START_REF] Köhler | Novelty responses to relational and non-relational information in the hippocampus and the parahippocampal region: a comparison based on event-related fMRI[END_REF], the spatial context of recalled/imagined episodes being retrieved early in the construction process (Weiler et al., 2010a). It has also been shown that the right hippocampus is responsive to the sense of (re)living the contextual episode [START_REF] Gilboa | Remembering our past: functional neuroanatomy of recollection of recent and very remote personal events[END_REF][START_REF] Graham | The neural basis of autobiographical and semantic memory: new evidence from three PET studies[END_REF][START_REF] Mayes | Recalling spatial information as a component of recently and remotely acquired episodic or semantic memories: an fMRI study[END_REF][START_REF] Piolino | Re-experiencing old memories via hippocampus: a PET study of autobiographical memory[END_REF][START_REF] Piolino | Reliving lifelong episodic autobiographical memories via the hippocampus: A correlative resting PET study in healthy middle-aged subjects[END_REF][START_REF] Steinvorth | Ecphory of autobiographical memories: an fMRI study of recent and remote memory retrieval[END_REF][START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF][START_REF] Viard | Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire lifespan of aged adults[END_REF]Viard et al., , 2011a;;St Jacques et al., in press) presumably by providing a spatial context to recall/imagine these events (Viard et al., 2011a;[START_REF] Burgess | A temporoparietal and prefrontal network for retrieving the spatial context of likelife events[END_REF].

Right hippocampal activation may also depend on the age of participants. Older adults show greater activation in the right hippocampus [START_REF] Ryan | Hippocampal complex and retrieval of recent and very remote autobiographical memories: evidence from functional magnetic resonance imaging in neurologically intact people[END_REF][START_REF] Viard | Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: An fMRI study[END_REF][START_REF] Nadel | Autobiographical memory retrieval and hippocampal activation as a function of repetition and the passage of time[END_REF][START_REF] Gilboa | Remembering our past: functional neuroanatomy of recollection of recent and very remote personal events[END_REF] compared to younger subjects [START_REF] Maguire | Aging affects the engagement of the hippocampus during autobiographical memory retrieval[END_REF]St Jacques et al., in press) which may reflect increased use or salience of spatial context in older subjects. Results of the meta-analysis indicate that older adults show greater right hippocampal activation compared to younger adults which is concordant with the hemispheric asymmetry reduction due to age observed in prefrontal regions (HAROLD model, Cabeza, 2002).

Overall, results from the meta-analysis show that laterality of hippocampal activation may depend on the methodology used to elicit past remembering and future envisioning, with strictly episodic events and specific cues more likely to activate the bilateral and right hippocampus, respectively. Interestingly, strictly episodic (re/pre)experiencing triggered by specific cues elicits greater activation in the left hippocampus, compared to episodic events triggered by specific cues. Differential roles have been attributed to the hippocampus according to its laterality, but also along its antero-posterior axis. Results from the metaanalysis show that the methodology used to elicit past and future (re/pre)experiencing may also account for differential antero-posterior activation.

Anterior hippocampus

ALE results show that the use of specific cues lead to greater activity in the anterior hippocampus compared to generic cues. The anterior hippocampus supports relational processing [START_REF] Chua | Evidence for a specific role of the anterior hippocampal region in successful associative encoding[END_REF][START_REF] Davachi | Multiple routes to memory: distinct medial temporal lobe processes build item and source memories[END_REF][START_REF] Jackson | Encoding activity in anterior medial temporal lobe supports subsequent associative recognition[END_REF], including flexible recombination of details for past and future events [START_REF] Preston | Hippocampal contribution to the novel use of relational information in declarative memory[END_REF]. Addis and Schacter (2008) showed that future-associated activity in the anterior hippocampus was associated with higher demands on recombination of details. Specific cues, which trigger precise personal events, may require immediate binding of disparate details compared to generic cues. [START_REF] Hoscheidt | Hippocampal activation during retrieval of spatial context from episodic and semantic memory[END_REF] showed that the anterior hippocampus is predominantly activated by episodic memory rather than by semantic memory.

Posterior hippocampus

Results from the meta-analysis show significantly greater posterior hippocampal activation for strictly episodic compared to episodic events, in line with our predictions, and this is observed particularly when (re/pre)experiencing is triggered by specific cues. The posterior hippocampus is predominantly activated by spatial memory [START_REF] Hoscheidt | Hippocampal activation during retrieval of spatial context from episodic and semantic memory[END_REF], spatial content (see [START_REF] Chadwick | Decoding individual episodic memory traces in the human hippocampus[END_REF] or navigation [START_REF] O'keefe | The Hippocampus as a Cognitive Map[END_REF][START_REF] Maguire | Knowing where and getting there: a human navigation network[END_REF][START_REF] Moser | Functional differentiation in the hippocampus[END_REF][START_REF] Ekstrom | Cellular networks underlying human spatial navigation[END_REF][START_REF] Hartley | The well-worn route and the path less travelled: distinct neural bases of route following and wayfinding in humans[END_REF]. Recent evidence shows that it may have a general role in recollection memory which is not limited to spatial memory [START_REF] Poppenk | A hippocampal marker of recollection memory ability among healthy young adults: contributions of posterior and anterior segments[END_REF]. The posterior hippocampus has been shown to respond to the amount of detail integrated into a coherent event, irrespective of past and future distinction (Addis et al., 2008). Compared to episodic events, strictly episodic events are indeed richer on phenomenological characteristics which include spatial content and level of detail. This posterior hippocampal activation is especially observed when (re/pre)experiencing is triggered by specific cues which directly trigger recall/imagination and its associated spatial context. The posterior hippocampus has a role in relational processing, as its anterior part, and is engaged by tasks requiring retrieval of relational information, for both past and future thinking (Addis et al., 2008).

Overall, results from the meta-analysis show that activity of the hippocampus along its antero-posterior axis may depend on the methodology used to elicit past and future episodic thinking, with specific cues and strictly episodic events more likely to recruit its anterior and posterior parts, respectively. Additionaly, when triggered exclusively by specific cues, (re/pre)experiencing strictly episodic events elicits greater activation in the posterior hippocampus, compared to episodic events. Yet, the hippocampus does not work alone and extra-hippocampal MTL regions also contribute to past and future episodic (re/pre)experiencing, in particular, via interactions with the hippocampus [START_REF] Viard | Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire lifespan of aged adults[END_REF][START_REF] Greenberg | Co-activation of the amygdala, hippocampus and inferior frontal gyrus during autobiographical memory retrieval[END_REF][START_REF] Maguire | Patterns of hippocampal-cortical interaction dissociate temporal lobe memory subsystems[END_REF]Söderlund et al., in press;Addis et al., 2004b[START_REF] Addis | Episodic simulation of future events is impaired in mild Alzheimer's disease[END_REF].

Contribution of the extra-hippocampal MTL regions to past and future episodic events

Laterality within the parahippocampal gyrus

Like the hippocampus, the parahippocampal gyrus can be subdivided depending on its laterality and along its antero-posterior axis. Although there is evidence of a functional specialization along its antero-posterior axis [START_REF] Graham | Going beyond LTM in the MTL: a synthesis of neuropsychological and neuroimaging findings on the role of the medial temporal lobe in memory and perception[END_REF], it is not yet clear if the left and right parahippocampal gyri have a differential role in past and future episodic thinking.

Hence, the laterality of the parahippocampal peaks resulting from the ALE analyses must be interpreted with caution and be considered as exploratory statistics. [START_REF] Tsukiura | Time-dependent contribution of the hippocampal complex when remembering the past: a PET study[END_REF] suggest that the parahippocampal gyrus, particularly on the right, may be implicated in the retrieval of topographical or spatial AMs and could be related to the recruitment of posterior visual areas during the retrieval of older episodic memories [START_REF] Niki | An fMRI study on the time-limited role of the medial temporal lobe in long-term topographical autobiographic memory[END_REF][START_REF] Mayes | Recalling spatial information as a component of recently and remotely acquired episodic or semantic memories: an fMRI study[END_REF]; for reviews, see [START_REF] Burgess | The human hippocampus and spatial and episodic memory[END_REF][START_REF] Moscovitch | Functional neuroanatomy of remote episodic, semantic and spatial memory: a unified account based on multiple trace theory[END_REF]. Indeed, the parahippocampal gyrus is involved in the retrieval of spatial compared to non-spatial contexts [START_REF] Burgess | A temporoparietal and prefrontal network for retrieving the spatial context of likelife events[END_REF][START_REF] King | Anterior prefrontal involvement in episodic retrieval reflects contextual interference[END_REF]; see also [START_REF] Bar | Scenes unseen: the parahippocampal cortex intrinsically subserves contextual associations, not scenes or places per se[END_REF][START_REF] Epstein | How reliable are visual context effects in the parahippocampal place area?[END_REF]Viard et al., 2011b) and responds selectively to visual scenes depicting places [START_REF] Epstein | A cortical representation of the local visual environment[END_REF]. The left parahippocampal gyrus remains online during elaboration of episodic AMs and might have a role in generating a complex coherent scene (St Jacques et al., in press). It is indeed involved in memory retrieval and encoding of spatial scenes [START_REF] Hoscheidt | Hippocampal activation during retrieval of spatial context from episodic and semantic memory[END_REF]. The parahippocampal gyrus (along with the hippocampus, retrosplenial cortex, posterior parietal cortex and ventro-medial prefrontal cortex) is also engaged during the construction of new fictitious scenes and when remembering both previously imagined and real personal experiences. This network supports (re)construction, maintenance and visualization of complex scenes (Hassabis et al., 2007).

Anterior parahippocampal gyrus

ALE results indicate that the anterior parahippocampal gyrus (entorhinal and perirhinal cortices) is activated for recognition compared to recall/imagine tasks and for episodic compared to strictly episodic events. Several models have proposed a functional segregation of the parahippocampal gyrus along its antero-posterior axis. According to [START_REF] Aggleton | Episodic memory, amnesia, and the hippocampalanterior thalamic axis[END_REF], the perirhinal cortex supports familiarity judgments and the relational memory view proposes that the perirhinal cortex supports memory for individual objects [START_REF] Eichenbaum | The medial temporal lobe and recognition memory[END_REF]. A complementary view, the binding of item and context theory (BIC), posits that it processes item information [START_REF] Diana | Imaging recollection and familiarity in the medial temporal lobe: a three-component model[END_REF], while the posterior parahippocampal gyrus (or parahippocampal cortex) processes context information (both spatial and non-spatial). The role of the hippocampus would be to bind together item and context (item-context associations) which are separately processed by the parahippocampal gyrus. Recognition tasks may prompt subjects to focus on the decision and familiarity rather than vivid recollection [START_REF] Piefke | Differential remoteness and emotional tone modulate the neural correlates of autobiographical memory[END_REF], explaining the greater anterior parahippocampal activation observed for recognition compared to recall tasks. Recruitment of the anterior parahippocampal gyrus suggests that familiarity judgments, mental manipulation of individual objects or processing of item information is greater for episodic than strictly episodic events.

Posterior parahippocampal gyrus

ALE results indicate that the posterior parahippocampal gyrus (parahippocampal cortex) is significantly more activated for recall/imagine compared to recognition tasks, in line with our predictions. Activity in the (bilateral) parahippocampal cortex during elaboration (along with the retrosplenial cortex, posterior cingulate cortex and precuneus) supports contextual processing [START_REF] Bar | Cortical analysis of visual context[END_REF]. The parahippocampal cortex is preferentially engaged during remembering, supporting retrieval of visuo-spatial details [START_REF] Addis | Episodic simulation of future events is impaired in mild Alzheimer's disease[END_REF]. Indeed, contextual processing and retrieval of visuo-spatial details are more engaged for recall/imagine compared to recognition tasks.

Results show greater posterior parahippocampal activation for generic compared to specific cues which was unexpected, as we predicted the opposite. We can only speculate that a generic cue, which is not as personally-oriented as specific cues, may require greater processing of contextual information to find an appropriate personal event corresponding to this generic cue.

Overall, results of the meta-analysis indicate that basic methodological choices may have an impact on activation within the parahippocampal gyrus, most notably along its anteroposterior axis, with episodic events and recognition tasks more likely to recruit its anterior part, compared to strictly episodic events and recall tasks respectively, the latter recruiting more its posterior part associated with greater contextual processing.

Amygdala

ALE results show greater activity within the bilateral amygdala for recognition compared to recall/imagine tasks. It is well known that the enhanced memory capability observed for emotional events is due, at least in part, to the amygdala's influence on encoding and storage of hippocampal-dependent memories, as suggested by many studies showing amygdala activation during the encoding of emotional stimuli predicts subsequent retention [START_REF] Cahill | Amygdala activity at encoding correlated with long-term, free recall of emotional information[END_REF][START_REF] Canli | Event-related activation in the human amygdala associates with later memory for individual emotional experience[END_REF][START_REF] Kensinger | Two routes to emotional memory: distinct neural processes for valence and arousal[END_REF]. While the left amygdala is more responsive to conscious, language-dependent processing [START_REF] Markowitsch | Differential contribution of right and left amygdala to affective information processing[END_REF][START_REF] Phelps | Emotion and cognition: insights from studies of the human amygdala[END_REF], the right amygdala has been shown to subserve a system of automatic detection of emotional stimuli [START_REF] Kensinger | Two routes to emotional memory: distinct neural processes for valence and arousal[END_REF][START_REF] Costafreda | Predictors of amygdala activation during the processing of emotional stimuli: a meta-analysis of 385 PET and fMRI studies[END_REF], which can be triggered by recognition tasks [START_REF] Clark-Foos | Recognition memory for valenced and arousing materials under conditions of divided attention[END_REF]. The right amygdalar activation for recognition compared to recall/imagine tasks may reflect this automatic process in emotional processing.

ALE results also show greater activity within the left amygdala for episodic compared to strictly episodic events, which was unexpected, as we predicted the opposite. Although the amygdala's role in the encoding of emotional stimuli is well documented, its role during recall/imagination of episodic events is not as clear [START_REF] Greenberg | Co-activation of the amygdala, hippocampus and inferior frontal gyrus during autobiographical memory retrieval[END_REF][START_REF] Daselaar | The spatiotemporal dynamics of autobiographical memory: neural correlates of recall, emotional intensity, and reliving[END_REF]. Several studies have detected amygdalar activation during the retrieval of emotional AMs [START_REF] Fink | Cerebral representation of one's own past: neural networks involved in autobiographical memory[END_REF][START_REF] Markowitsch | Right amygdalar and temporofrontal activation during autobiographic, but not fictitious memory retrieval[END_REF][START_REF] Markowitsch | Engagement of lateral and medial prefrontal areas in the ecphory of sad and happy autobiographical memories[END_REF]Maguire and Frith, 2003a;[START_REF] Greenberg | Co-activation of the amygdala, hippocampus and inferior frontal gyrus during autobiographical memory retrieval[END_REF][START_REF] Daselaar | The spatiotemporal dynamics of autobiographical memory: neural correlates of recall, emotional intensity, and reliving[END_REF] or when imagining positive future events [START_REF] Sharot | How emotion enhances the feeling of remembering[END_REF], although sometimes subthresholded (Addis et al., 2004a) or inconsistently even when emotions were specifically probed (Maguire and Frith, 2003a;[START_REF] Piefke | Differential remoteness and emotional tone modulate the neural correlates of autobiographical memory[END_REF].

Conclusion

The present meta-analysis explored the effect of methodological factors on MTL activity, in an attempt to explain the contradictory findings concerning MTL laterality and antero-posterior activity found in the neuroimaging literature on past and future (re/pre)experiencing.

Four main results emerge: (1) specific cues tend to recruit the right anterior hippocampus more than generic cues, (2) recall/imagine tasks tend to activate the posterior parahippocampal gyrus more than recognition tasks, (3) (re/pre)experiencing strictly episodic events recruits the bilateral posterior hippocampus more than episodic events and (4) older subjects activate more the right anterior hippocampus compared to younger subjects, confirming our predictions. Importantly, our results stress that strictly episodic events triggered by specific cues elicits greater left posterior hippocampal activation than standard episodic memory/imagination elicited by specific cues. These findings suggest that basic methodological choices have an impact on MTL laterality and antero-posterior activity. Here, we investigated the effect of four factors only and focussed exclusively on the MTL. Future meta-analyses may address whether other factors (e.g., differences in time frames, number of memories recollected, trial designs, re-encoding processes…) are likely to influence MTL activity and, more broadly, their impact on other brain regions elicited by episodic (re/pre)experiencing. Multi-voxel pattern analysis and similar approaches will be important to factor in future considerations of this topic, once a sufficient number of studies have been published. Abbreviations: ANOVA = analysis of variance; ctl = control; F = future; gp = group; P = past; PE = personal event; PM = parametric modulation.

* Multi-variate analyses ** For the future, recall corresponds to the imagination task. For abbreviations, see Table 3. For abbreviations, see Table 3.

Figure 1 :

 1 Figure 1: ALE maps thresholded at p<0.05 corrected for the following comparisons: (top left) Generic > Specific cues centered on the bilateral posterior parahippocampal gyrus; (top right) Specific > Generic cues centered on the right anterior hippocampus; (middle left) Recognition > Recall/imagine tasks centered on the bilateral anterior parahippocampal gyrus; (middle right) Recall/imagine > Recognition tasks centered on the left posterior parahippocampal gyrus; (bottom left) Episodic > Strictly episodic events centered on the left anterior parahippocampal gyrus; (bottom right) Strictly episodic > Episodic events centered on the bilateral posterior hippocampus.

Table 1 :

 1 Studies included in the meta-analysis, specifying the contrast, number of subjects, nature of the information retrieved (episodic or strictly episodic), type of task (recognition or recall), type of cue (generic or specific) and number of foci falling within the MTL (hippocampus, parahippocampal gyrus, amygdala).

	Study	Contrast	Past /Future	N	Age	Cue Task** Nature Foci
	1 Abraham et al., 2008a	PE-ctl	F	20	26	generic recog episodic 3
	2 Addis et al., 2004a	PE-ctl and PM	P	14	20-40	specific recall	strict	13
	3 Addis et al., 2004b*	PE-ctl	P	14	28	specific recall	strict	2
	4 Addis et al., 2007	PE-ctl and PM	F	14	23	generic recall	strict	4
	5 Addis et al., 2008	PE-ctl and ANOVA	F	16	23	generic recall	strict	2
	6 Addis et al., 2009*	PE-ctl	F	18	21,9	generic recall	strict	5
	7 Addis et al., 2011a	PE-ctl	F	15	18-33	generic recall	strict	2
	8 Addis et al., 2011b*	PE-ctl	F	28 gp1=19,5;	generic recall episodic 3
					gp2=72,9
	9 Addis et al., 2012*	PE-ctl	P	15	22	specific recall	strict	4
	10 Botzung et al., 2008b	PE-ctl	P	10	42,4	specific recall episodic 1
	11 Burianova et al., 2007*	PE-ctl	P	12	26,8	generic recall	strict	1
	12 Cabeza et al., 2004	PE-ctl and ANOVA	P	13	20,8	specific recog episodic 3
	13 Daselaar et al., 2008	PM	P	17	18-35	generic recall	strict	3
	14 Denkova et al., 2006a	PE-ctl	P	10	42,4	specific recall episodic 2
	15 Denkova et al., 2006b	PE-ctl	P	10	40,6	specific recall episodic 1
	16 Donix et al., 2010	PE-ctl	P	15	gp1=28;	specific recall episodic 1
					gp2=60,5
	17 Fink et al., 1996	PE-ctl	P	7		specific recall episodic 1
	18 Ford et al., 2011	PE-ctl	P	16	21-37	generic recall	strict	3
	19 Gardini et al., 2006	PE-ctl	P	14	37,93	generic recall	strict	3
	20 Gilboa et al., 2004	PE-ctl	P	9	50,75	specific recall	strict	3

Table 4 :

 4 Results from the ALE meta-analyses for Recognition versus Recall tasks.

					Volume	Peak ALE
	Region	Lat Axis BA	(mm 3 )	Value	x	y	z
	Recognition > recall
	Amygdala	R	A	34	3112	3,540	23	2	-16
	Parahippocampal Gyrus	R	A	28		3,353	22	6	-15
	Parahippocampal Gyrus	R	A	28		2,549	20 -18 -16
	Parahippocampal Gyrus	L	A	28	1120	2,400	-20 -14 -20
	Parahippocampal Gyrus	L	A	34		2,304	-16 -16 -22
	Amygdala	L			120	2,050	-26	0	-18
	Parahippocampal Gyrus	L	A	34		2,034	-30	2	-18
	Recall > recognition
	Parahippocampal Gyrus	L	P	30	544	1,855	-24 -36 4

Table 7 :

 7 Results of the ALE comparison between data from younger and older subjects.

				Volume	Peak ALE
	Region	Lat Axis BA	(mm 3 )	Value	x	y	z
	Older > younger
	Parahippocampal Gyrus	R	A 35	5816	3.090	25 -17 -11
	Hippocampus	R	A		2.878	32 -18 -16
	Parahippocampal Gyrus	R	P 27		2.576	12.8 -30 1.6
	Parahippocampal Gyrus	L	P 36	2896	3.719	-33 -23 -16
	Parahippocampal Gyrus	L	P 36		3.540	-35 -26 -13
	Amygdala	L		2352	2.214	-18 -4 -10

Study

Reason for exclusion 1 [START_REF] Andreasen | Remembering the past: two facets of episodic memory explored with positron emission tomography[END_REF] No MTL activation 2 [START_REF] Andreasen | The cerebellum plays a role in conscious episodic memory retrieval[END_REF] No MTL activation 3 Botzung et al., 2008a No MTL coordinates provided 4 Burianova et al., 2010 All memory conditions (including semantic) > control 5 [START_REF] Conway | The neuroanatomy of autobiographical memory: a slow cortical potentials (SCPs) study of autobiographical memory retrieval[END_REF] Electroencephalography 6 [START_REF] Conway | Neurophysiological correlates of memory for experienced and imagined events[END_REF] Electroencephalography 7 [START_REF] Conway | A positron emission tomography (PET) study of autobiographical memory retrieval[END_REF] No MTL activation 8 D' Argembeau et al., 2008 Positive > negative future events 9 D' Argembeau et al., 2010 No MTL activation for the contrast of interest* 10 [START_REF] Graham | The neural basis of autobiographical and semantic memory: new evidence from three PET studies[END_REF] No MTL coordinates provided 11 Maddock et al., 2001 No MTL coordinates provided 12 [START_REF] Maguire | Patterns of hippocampal-cortical interaction dissociate temporal lobe memory subsystems[END_REF] All memory conditions (including semantic) > control 13 [START_REF] Maguire | Activity in prefrontal cortex, not hippocampus, varies parametrically with the increasing remoteness of memories[END_REF] All memory conditions (including semantic) > control 14 [START_REF] Milton | An fMRI study of long-term everyday memory using SenseCam[END_REF] No MTL activation for the contrast of interest* 15 [START_REF] Niki | An fMRI study on the time-limited role of the medial temporal lobe in long-term topographical autobiographic memory[END_REF] Recent > remote AMs 16 [START_REF] Nyberg | Brain imaging of human memory systems: between-systems similarities and within-system differences[END_REF] No MTL activation 17 Piefke et al., 2005 Same contrasts as [START_REF] Piefke | Differential remoteness and emotional tone modulate the neural correlates of autobiographical memory[END_REF]18 Piolino et al., 2004 No MTL coordinates provided 19 St [START_REF] St Jacques | The short and long of it: neural correlates of temporal-order memory for autobiographical events[END_REF] Inappropriate contrast (temporal-order judgments) 20 [START_REF] Steinvorth | Ecphory of autobiographical memories: an fMRI study of recent and remote memory retrieval[END_REF] No MTL coordinates provided 21 Summerfield et al., 2009 Conjunction with semantic condition 22 Tulving et al., 1989 No MTL coordinates provided 23 [START_REF] Viard | Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire lifespan of aged adults[END_REF] No MTL coordinates provided 24 Weiler et al., 2011 Electroencephalography Abbreviations: > = versus.

* Contrast of interest: episodic event condition (past or future) compared to control condition. For abbreviations, see Table 3. For abbreviations, see Table 3.