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Abstract

Although growing evidence has shown that remembering the past and imagining the future recruit a common core network of frontal-parietal-temporal regions, the extent to which these regions contribute to the temporal dimension of autobiographical thought remains unclear. In this fMRI study, we focused on the event-sequencing aspect of time and examined whether ordering past and future events involve common neural substrates. Participants had to determine which of two past (or future) events occurred (or would occur) before the other, and these order judgments were compared with a task requiring to think about the content of the same past or future events. For both past and future events, we found that the left posterior hippocampus was more activated when establishing the order of events, whereas the anterior hippocampus was more activated when representing their content. Aside from the hippocampus, most of the brain regions that were activated when thinking about temporal order (notably the intraparietal sulcus, dorsolateral pFC, dorsal anterior cingulate, and visual cortex) lied outside the core network and may reflect the involvement of controlled processes and visuospatial imagery to locate events in time. Collectively, these findings suggest (a) that the same processing operations are engaged for ordering past events and planned future events in time, (b) that anterior and posterior portions of the hippocampus are involved in processing different aspects of autobiographical thought, and (c) that temporal order is not necessarily an intrinsic property of memory or future thought but instead requires additional, controlled processes.

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... The leading hypothesis suggests multiple temporal "codes" for these durations (Conway & Pleydell-Pearce, 2000;Friedman, 1987;Friedman & Wilkins, 1985), because these codes depend on multiple sources of information (e.g., memory trace strength, shared contexts, interevent links [chaining], time tags, intertemporal choice, and temporal discounting; Bulley & Schacter, 2020;D'Argembeau, 2012D'Argembeau, , 2020Schacter et al., 2012). The logarithmic character of the mental time line (Gauthier & van Wassenhove, 2016;D'Argembeau, Jeunehomme, Majerus, Bastin, & Salmon, 2015;Arzy, Adi-Japha, & Blanke, 2009) may suggest a bipartition for the time range closer to the "now" on the one hand and the logarithmic series distribution's tail on the other. Another kind of bipartition of the memory time code are "forward" and "backward" forms (see Arzy, Molnar-Szakacs, & Blanke, 2008;Friedman, 1993). ...
... A simpler hypothesis suggests a uniform code for time in which long and short timescales are coded similarly. Several neuroimaging studies have investigated the neural correlates of temporal order memory for autobiographical events (D'Argembeau et al., 2015;Nielson, Smith, Sreekumar, Dennis, & Sederberg, 2015;St. Jacques, Rubin, LaBar, & Cabeza, 2008). ...
Article
While recalling life events, we reexperience events of different durations, ranging across varying temporal scales, from several minutes to years. However, the brain mechanisms underlying temporal cognition are usually investigated only in small-scale periods—milliseconds to minutes. Are the same neurocognitive systems used to organize memory at different temporal scales? Here, we asked participants to compare temporal distances (time elapsed since event) to personal events at four different temporal scales (hour, day, week, and month) under fMRI. Cortical activity showed temporal scale sensitivity at the medial and lateral parts of the parietal lobe, bilaterally. Activity at the medial parietal cortex also showed a gradual progression from large- to small-scale processing, along a posterior–anterior axis. Interestingly, no sensitivity was found along the hippocampal long axis. In the medial scale-sensitive region, most of the voxels were preferentially active for the larger scale (month), and in the lateral region, scale selectivity was higher for the smallest scale (hour). These results demonstrate how scale-selective activity characterizes autobiographical memory processing and may provide a basis for understanding how the human brain processes and integrates experiences across timescales in a hierarchical manner.
... year) to locate future events in time (Friedman, 2000(Friedman, , 2002(Friedman, , 2005 Thomsen, 2015) for locating imagined events in future times, and some planned events might serve as reference points (or temporal landmarks; Shum, 1998) for determining the location of other future events. Interestingly, a recent fMRI study has shown that judgments of temporal order recruit a common neural network for past and future events, suggesting that (at least partly) similar processes are used for determining the times of past and future events (D'Argembeau, Jeunehomme, Majerus, Bastin, & Salmon, 2015). However, the precise nature of these processes remains to be investigated in detail. ...
... Considerable evidence has indicated that the temporal location of past events is mainly reconstructive and inferential (Friedman, 1993(Friedman, , 2004Thompson et al., 1993Thompson et al., , 1996Shum, 1998), and recent studies suggest that similar mechanisms are involved in estimating the times of future events (Ben D'Argembeau et al., 2015). ...
Thesis
The aim of this thesis was to investigate the processes involved in the temporal location of personal future events in healthy individuals and in patients with schizophrenia. To do so, we used a think-aloud procedure in three experimental studies to analyse the strategies used to determine the times of autobiographical events. In Study 1, we found that participants mostly used reconstructive/inferential processes to date events. They relied most frequently on autobiographical knowledge (i.e., lifetime periods/extended events) and general knowledge to reconstruct or infer the times of events, both for past and future events. In Study 2, we found that personal goals influenced the temporal location process by increasing the direct access to the times of important future events, and by favouring the use of autobiographical knowledge to infer the times of events when dates are not directly accessible. In Study 3, we found that patients with schizophrenia had difficulties to rely on episodic information to reconstruct or infer the times of personal events, and made more errors when they were asked to temporally order the previously dated events. Based on these novel findings, we propose a dual-process model of the temporal location of autobiographical events that articulates the cognitive mechanisms engaged in the dating of past and future events.
... Temporal sequences play a central role in the organization of autobiographical representations at these different levels of hierarchical knowledge. In line with our hypothesis, neuroimaging studies revealed higher activation in the cerebellum when processing the temporal order of past and future events compared to simply processing their content [38], and when thinking about past and future events that are organized in themes and sequences [39]. ...
... The rat is an excellent laboratory animal for operant conditioning [33][34][35][36][37][38][39][40][41][42] tasks and the solution of unpredictable environmental situations [71]. Rats can develop prosocial behaviors aimed to interact for the joint solution of complex operant conditioning tasks [72] and to select between food or social rewards [73]. ...
... 34,105-107 A common interpretation of this model is that the anterior hippocampus is recruited for coarse-based information, such as recovering general emotional information or object-based conceptual information, whereas the posterior hippocampus is critical for retrieving fine-grained perceptual or geometrically based relations, such as the location of a landmark in space or particular temporal sequences. [108][109][110] Alternate but not orthogonal views are that the anterior and posterior aspects process familiar versus contextual details of events. [111][112][113] Within our framework, these findings and formulations can be used to predict how hippocampal segments will support mental construction on the basis of the noted retrieval characteristics of construction. ...
... 103,110,129 Beyond spatial construction, the posterior hippocampus is involved in a host of other tasks that require relating together specific experienced details. Indeed, there is now evidence that the posterior hippocampus supports fine-grained representations, even when these occur in temporal "space" 108,109,130,131 (for recent views on this topic, see Ref. 132). ...
Article
Much has been learned about the processes that support the remembrance of past autobiographical episodes and their importance for a number of cognitive tasks. This work has focused on hippocampal contributions to constructing coherent mental representations of scenarios for these tasks, which has opened up new questions about the underlying hippocampal mechanisms. We propose a new framework to answer these questions, which incorporates task demands that prompt hippocampal contributions to mental construction, the online formation of such mental representations, and how these demands relate to the functional organization of the hippocampus. Synthesizing findings from autobiographical memory research, our framework suggests that the interaction of two task characteristics influences the recruitment of the hippocampus: (1) the degree of task open-endedness (quantified by the presence/absence of a retrieval framework) and (2) the degree to which the integration of perceptual details is required. These characteristics inform the relative weighting of anterior and posterior hippocampal involvement, following an organizational model in which the anterior and posterior hippocampus support constructions on the basis of conceptual and perceptual representations, respectively. The anticipated outcome of our framework is a refined understanding of hippocampal contributions to memory and to the host of related cognitive functions.
... Regions within the parietal lobe and, in particular, the intraparietal sulcus have been implicated in the encoding of order (Attout et al., 2014;Marshuetz et al., 2006) and temporal information (D'Argembeau et al., 2015). Furthermore, processing the temporal and spatial dimensions of mental events engages a common parietal region (D'Argembeau et al., 2015;Gauthier and van Wassenhove, 2016;Parkinson et al., 2014;Peer et al., 2015). ...
... Regions within the parietal lobe and, in particular, the intraparietal sulcus have been implicated in the encoding of order (Attout et al., 2014;Marshuetz et al., 2006) and temporal information (D'Argembeau et al., 2015). Furthermore, processing the temporal and spatial dimensions of mental events engages a common parietal region (D'Argembeau et al., 2015;Gauthier and van Wassenhove, 2016;Parkinson et al., 2014;Peer et al., 2015). Accordingly, right brain damaged patients with left neglect are impaired in representing past events, with the past being typically mapped on the left portion of the MTL (Saj et al., 2014; see also Bonato et al., 2016). ...
Article
The spatial representation of numerical and temporal information is thought to be rooted in our multisensory experiences. Accordingly, we may expect visual or auditory deprivation to affect the way we represent numerical magnitude and time spatially. Here, we systematically review recent findings on how blind and deaf individuals represent abstract concepts such as magnitude and time (e.g., past/future, serial order of events) in a spatial format. Interestingly, available evidence suggests that sensory deprivation does not prevent the spatial “re-mapping” of abstract information, but differences compared to normally sighted and hearing individuals may emerge depending on the specific dimension considered (i.e., numerical magnitude, time as past/future, serial order). Herein we discuss how the study of sensory deprived populations may shed light on the specific, and possibly distinct, mechanisms subserving the spatial representation of these concepts. Furthermore, we pinpoint unresolved issues that need to be addressed by future studies to grasp a full understanding of the spatial representation of abstract information associated with visual and auditory deprivation.
... For instance, people might use culturally shared knowledge about the timing of major life events (e.g., marriage, first job, retirement; Berntsen & Rubin, 2004) and more idiosyncratic autobiographical periods (e.g., when I'll move to France;D'Argembeau & Mathy, 2011;Thomsen, 2015) for locating imagined events in future times, and some planned events might serve as reference points (or temporal landmarks; Shum, 1998) for determining the location of other future events. Interestingly, a recent functional magnetic resonance imaging study has shown that judgments of temporal order recruit a common neural network for past and future events, suggesting that (at least partly) similar processes are used for determining the times of past and future events (D'Argembeau, Jeunehomme, Majerus, Bastin, & Salmon, 2015). However, the precise nature of these processes remains to be investigated in detail. ...
Article
Humans have the remarkable ability to mentally travel through past and future times. However, while memory for the times of past events has been much investigated, little is known about how imagined future events are temporally located. Using a think-aloud protocol, we found that the temporal location of past and future events is rarely directly accessed, but instead mostly relies on reconstructive and inferential strategies. References to lifetime periods and factual knowledge (about the self, others, and the world) were most frequently used to determine the temporal location of both past and future events. Event details (e.g., places, persons, or weather conditions) were also used, but mainly for past events. Finally, the results showed that events whose temporal location was directly accessed were judged more important for personal goals. Together, these findings shed new light on the mechanisms involved in locating personal events in past and future times.
... Notably, recent evidence has shown that temporal order processing engage the visual cortex and the precuneus, as well as the intraparietal sulcus, brain areas that are part of the neural network linked to visuospatial imagery and visuospatial attention (D'Argembeau, Jeunehomme, Majerus, Bastin, & Salmon, 2015;see also Rinaldi, Brugger, Bockisch, Bertolini, & Girelli, 2015). This study adds to the existing evidence by indicating that the embodied sagittal MTL engages also sensorimotor representations (Miles et al., 2010). ...
Article
Time is often conceptualized in terms of space. For instance, the phrase “to take a step back in time” metaphorically implies a mental time travel toward the past as well as an egocentric backward motion in physical space. A prevalent representation of temporal concepts, indeed, construes the past and the future as respectively behind and in front of the ego. The egocentric Mental Time Line (MTL) is supposed to originate from our walking experience in the physical world, though direct evidence supporting this representation is still needed. On these grounds, here we reasoned that if the egocentric MTL originates from walking, temporal processing should affect step movements along the sagittal space (i.e., both in the front and in the back space). By recording whole-body movement kinematics, we show that participants initiated faster steps backward in response to past- than to future-related words, whereas they initiated faster steps forward in response to future- than to past-related words. These results provide striking evidence in support of the moving ego metaphor of time, according to which we would approach future events and leave them behind, as moving through a mental time line projected on a physical space.
... The pre-SMA has a known role in planning actions (Kennerley et al. 2004), and a rostral region adjacent to our cluster is important in the process through which participants choose actions which are minimally constrained by the environment (Nachev et al. 2005). Importantly, several recent studies have extended the role of the pre-SMA beyond motor planning by implicating it, as well as the hippocampus, in the generation of detailed personal goals (Spreng et al. 2015) as well as in the ordering of future events (D'Argembeau et al. 2015). Our data build on these observations by illustrating the role that future thought during the mind-wandering state plays in this process. ...
Article
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Human cognition is not limited to the available environmental input but can consider realities that are different to the here and now. We describe the cognitive states and neural processes linked to the refinement of descriptions of personal goals. When personal goals became concrete, participants reported greater thoughts about the self and the future during mind-wandering. This pattern was not observed for descriptions of TV programmes. Connectivity analysis of participants who underwent a resting-state functional magnetic resonance imaging scan revealed neural traits associated with this pattern. Strong hippocampal connectivity with ventromedial pre-frontal cortex was common to better-specified descriptions of goals and TV programmes, while connectivity between hippocampus and the pre-supplementary motor area was associated with individuals whose goals were initially abstract but became more concrete over the course of the experiment. We conclude that self-generated cognition that arises during the mind-wandering state can allow goals to be refined, and this depends on neural systems anchored in the hippocampus.
... We note that PA is known to act preferentially on egocentric spatial representations (Gossmann, Kastrup, Kerkhoff, Lopez-Herrero, & Hildebrandt, 2013), which might explain why the PA manipulation had a selective effect on the self-reference component of MTT, which requires determining the position of single events in time with respect to the self. Recent research has also shown that regions within the PPC mediate processes necessary to determine the temporal order of events (D'Argembeau, Jeunehomme, Majerus, Bastin, & Salmon, 2015), and support the spatial representation of time (Bueti & Walsh, 2009). These processes are likely at work during self-referencing. ...
Article
Accumulating evidence suggests that humans process time and space in similar veins. Humans represent time along a spatial continuum, and perception of temporal durations can be altered through manipulations of spatial attention by prismatic adaptation (PA). Here, we investigated whether PA-induced manipulations of spatial attention can also influence more conceptual aspects of time, such as humans' ability to travel mentally back and forward in time (mental time travel, MTT). Before and after leftward- and rightward-PA, participants projected themselves in the past, present or future time (i.e., self-projection), and, for each condition, determined whether a series of events were located in the past or the future with respect to that specific self-location in time (i.e., self-reference). The results demonstrated that leftward and rightward shifts of spatial attention facilitated recognition of past and future events, respectively. These findings suggest that spatial attention affects the temporal processing of the human self.
... Children exposed to early adversity may be more dependent on the latter circuit (198). New research also links mPFC to the production of multimodal imagery (199)(200)(201)(202)(203) and spatiotemporal orientation (204,205). ...
Article
Adverse childhood experiences can deleteriously affect future physical and mental health, increasing risk for many illnesses, including psychiatric problems, sleep disorders, and, according to the present hypothesis, idiopathic nightmares. Much like post-traumatic nightmares, which are triggered by trauma and lead to recurrent emotional dreaming about the trauma, idiopathic nightmares are hypothesized to originate in early adverse experiences that lead in later life to the expression of early memories and emotions in dream content. Accordingly, the objectives of this paper are to (1) review existing literature on sleep, dreaming and nightmares in relation to early adverse experiences, drawing upon both empirical studies of dreaming and nightmares and books and chapters by recognized nightmare experts and (2) propose a new approach to explaining nightmares that is based upon the Stress Acceleration Hypothesis of mental illness. The latter stipulates that susceptibility to mental illness is increased by adversity occurring during a developmentally sensitive window for emotional maturation—the infantile amnesia period—that ends around age 3½. Early adversity accelerates the neural and behavioral maturation of emotional systems governing the expression, learning, and extinction of fear memories and may afford short-term adaptive value. But it also engenders longterm dysfunctional consequences including an increased risk for nightmares. Two mechanisms are proposed: (1) disruption of infantile amnesia allows normally forgotten early childhood memories to influence later emotions, cognitions and behavior, including the common expression of threats in nightmares; (2) alterations of normal emotion regulation processes of both waking and sleep lead to increased fear sensitivity and less effective fear extinction. These changes influence an affect network previously hypothesized to regulate fear extinction during REM sleep, disruption of which leads to nightmares. This network consists of a fear circuit that includes amygdala, hippocampus, and medial prefrontal cortex and whose substantial overlap with the stress acceleration findings allows the latter to be incorporated into a wider, more developmentally coherent framework.
... A similar study reported reduced performance for cerebellar patients with isolated ischemic lesions as compared to healthy controls on sequencing tasks, especially when the sequences involved biological movements [122]. In yet another study, participants had to judge whether personal events (e.g., fetch parents at the airport) were ordered correctly or whether they really happened [123]. Among other regions in the cortex, the left posterior cerebellum was activated during order judgments, but not during reality judgments. ...
Article
Full-text available
The traditional view on the cerebellum is that it controls motor behavior. Although recent work has revealed that the cerebellum supports also nonmotor functions such as cognition and affect, only during the last 5 years it has become evident that the cerebellum also plays an important social role. This role is evident in social cognition based on interpreting goal-directed actions through the movements of individuals (social “mirroring”) which is very close to its original role in motor learning, as well as in social understanding of other individuals’ mental state, such as their intentions, beliefs, past behaviors, future aspirations, and personality traits (social “mentalizing”). Most of this mentalizing role is supported by the posterior cerebellum (e.g., Crus I and II). The most dominant hypothesis is that the cerebellum assists in learning and understanding social action sequences, and so facilitates social cognition by supporting optimal predictions about imminent or future social interaction and cooperation. This consensus paper brings together experts from different fields to discuss recent efforts in understanding the role of the cerebellum in social cognition, and the understanding of social behaviors and mental states by others, its effect on clinical impairments such as cerebellar ataxia and autism spectrum disorder, and how the cerebellum can become a potential target for noninvasive brain stimulation as a therapeutic intervention. We report on the most recent empirical findings and techniques for understanding and manipulating cerebellar circuits in humans. Cerebellar circuitry appears now as a key structure to elucidate social interactions.
... Because clusters of SPW-Rs typically occur also in isolated hippocampal slices (103,116) it has been speculated that clusters may represent an endogenous default mode of SPW-Rs generation that can provide the basis for organizing patterns of activity independently of the actual current behavior (117). This conforms to the suggested role of SPW-Rs in imaging not-yet experienced events (89)(90)(91) and is consistent with the proposed role of the hippocampus in episodic future thinking (118)(119)(120)(121). It is therefore proposed that the ventral hippocampus dominate the endogenous initiation of SPW-Rs in the hippocampus and that the different pace of SPW-Rs inside clusters may reflect local requirements for optimal induction of synaptic plasticity in the two hippocampal segments (30). ...
Article
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The elongated structure of the hippocampus is critically involved in brain functions of profound importance. The segregation of functions along the longitudinal (septotemporal or dorsoventral) axis of the hippocampus is a slowly developed concept and currently is a widely accepted idea. The segregation of neuroanatomical connections along the hippocampal long axis can provide a basis for the interpretation of the functional segregation. However, an emerging and growing body of data strongly suggests the existence of endogenous diversification in the properties of the local neural network along the long axis of the hippocampus. In particular, recent electrophysiological research provides compelling evidence demonstrating constitutively increased network excitability in the ventral hippocampus with important implications for the endogenous initiation and propagation of physiological hippocampal oscillations yet, under favorable conditions it can also drive the local network towards hyperexcitability. In addition, important specializations in the properties of dorsal and ventral hippocampal synapses may support an optimal signal processing that contributes to the effective execution of the distinct functional roles played by the two hippocampal segments.
... While the mechanisms and functions of episodic future thought have been intensively studied in the past few years (Schacter, Benoit, & Szpunar, 2017), little is known about how people estimate the times when imagined future events are expected to happen (Friedman, 2005). A recent study showed that the strategies used to date past and future events are largely the same, suggesting that common processes may be used for locating personal events in past and future times (Ben Malek, Berna, & D'Argembeau, 2017; see also D'Argembeau, Jeunehomme, Majerus, Bastin, & Salmon, 2015). It was found that participants most frequently used general knowledge about their life to infer or reconstruct temporal locations, in line with previous research on memory for the time of past events (for review, see Friedman, 1993Friedman, , 2004Thompson, Skowronski, Larsen, & Betz, 1996). ...
... Importance of developing ability to remember event-sequencing aspect of time can be supported by its key role in future planning. Remembering temporal order of events or event components with respect to each other may be especially helpful for keeping track of goal progress and organizing current and future behavior (D' Argembeau Jeunehomme, Majerus, Bastin, & Salmon, 2014;Conway, 2009). Thus, even younger children are expected to engage in monitoring, reporting, and planning of their activities in some temporally organized ways. ...
Chapter
Stereotypic backhanded compliments are defined as compliments that praise a stigmatized individual for violating a negative stereotype (e.g., "You're smart, for a woman."). Although commonly used in everyday language, few studies have examined these comments empirically. As such, the purpose of the present work was twofold. First, we sought to determine if people recognize such comments as prejudiced. Second, we sought to explore the possible consequences that result from exposure to stereotypic backhanded compliments. In Study 1, women rated a commenter who used such compliments as more sexist than men. Study 2 replicated this effect and through the use of mediational analyses also found a contamination effect. Women were more likely than men to dislike the backhanded complimenter and this dislike subsequently contaminated women's evaluation of the person receiving the compliment. We discuss the implications of this work for understanding the social function of backhanded compliments.
Article
Neuroimaging data indicate that episodic memory (i.e., remembering specific past experiences) and episodic simulation (i.e., imagining specific future experiences) are associated with enhanced activity in a common set of neural regions, often referred to as the core network. This network comprises the hippocampus, parahippocampal cortex, lateral and medial parietal cortex, lateral temporal cortex, and medial prefrontal cortex. Evidence for a core network has been taken as support for the idea that episodic memory and episodic simulation are supported by common processes. Much remains to be learned about how specific core network regions contribute to specific aspects of episodic simulation. Prior neuroimaging studies of episodic memory indicate that certain regions within the core network are differentially sensitive to the amount of information recollected (e.g., the left lateral parietal cortex). In addition, certain core network regions dissociate as a function of their timecourse of engagement during episodic memory (e.g., transient activity in the posterior hippocampus and sustained activity in the left lateral parietal cortex). In the current study, we assessed whether similar dissociations could be observed during episodic simulation. We found that the left lateral parietal cortex modulates as a function of the amount of simulated details. Of particular interest, while the hippocampus was insensitive to the amount of simulated details, we observed a temporal dissociation within the hippocampus: transient activity occurred in relatively posterior portions of the hippocampus and sustained activity occurred in anterior portions. Because the posterior hippocampal and lateral parietal findings parallel those observed previously during episodic memory, the present results add to the evidence that episodic memory and episodic simulation are supported by common processes. Critically, the present study also provides evidence that regions within the core network support dissociable processes.
Article
Recent behavioral work suggests that an episodic specificity induction-brief training in recollecting the details of a past experience-enhances performance on subsequent tasks that rely on episodic retrieval, including imagining future experiences, solving open-ended problems, and thinking creatively. Despite these far-reaching behavioral effects, nothing is known about the neural processes impacted by an episodic specificity induction. Related neuroimaging work has linked episodic retrieval with a core network of brain regions that supports imagining future experiences. We tested the hypothesis that key structures in this network are influenced by the specificity induction. Participants received the specificity induction or one of two control inductions and then generated future events and semantic object comparisons during fMRI scanning. After receiving the specificity induction compared with the control, participants exhibited significantly more activity in several core network regions during the construction of imagined events over object comparisons, including the left anterior hippocampus, right inferior parietal lobule, right posterior cingulate cortex, and right ventral precuneus. Induction-related differences in the episodic detail of imagined events significantly modulated induction-related differences in the construction of imagined events in the left anterior hippocampus and right inferior parietal lobule. Resting-state functional connectivity analyses with hippocampal and inferior parietal lobule seed regions and the rest of the brain also revealed significantly stronger core network coupling following the specificity induction compared with the control. These findings provide evidence that an episodic specificity induction selectively targets episodic processes that are commonly linked to key core network regions, including the hippocampus.
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Psychiatric disorders are often caused by partial heterogeneous disinhibition in cognitive networks, controlling sequential and spatial working memory (SWM). Such dynamic connectivity changes suggest that the normal relationship between the neuronal components within the network deteriorates. As a result, competitive network dynamics is qualitatively altered. This dynamics defines the robust recall of the sequential information from memory and, thus, the SWM capacity. To understand pathological and non-pathological bifurcations of the sequential memory dynamics, here we investigate the model of recurrent inhibitory-excitatory networks with heterogeneous inhibition. We consider the ensemble of units with all-to-all inhibitory connections, in which the connection strengths are monotonically distributed at some interval. Based on computer experiments and studying the Lyapunov exponents, we observed and analyzed the new phenomenon-clustered sequential dynamics. The results are interpreted in the context of the winnerless competition principle. Accordingly, clustered sequential dynamics is represented in the phase space of the model by two weakly interacting quasi-attractors. One of them is similar to the sequential heteroclinic chain-the regular image of SWM, while the other is a quasi-chaotic attractor. Coexistence of these quasi-attractors means that the recall of the normal information sequence is intermittently interrupted by episodes with chaotic dynamics. We indicate potential dynamic ways for augmenting damaged working memory and other cognitive functions.
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The representation and maintenance of serial order information is one of the main functions of verbal short-term memory (STM) but its neural correlates remain poorly understood. We show here that the neural substrates allowing for coding of order information in STM are shared with those supporting ordinal processing in the numerical and alphabetical domains. We designed an fMRI experiment determining the neural substrates sensitive to ordinal distance effects in numerical judgment, alphabetical judgment and serial order STM tasks. Null conjunction analyses for parametric ordinal distance effects showed a common involvement of the horizontal segment of the left intraparietal sulcus over the three tasks; in addition, right intraparietal sulcus involvement was also observed for ordinal distance effects in the STM and numerical judgment tasks. These findings demonstrate that shared neural correlates in the intraparietal cortex support processing of order information in verbal STM, number and alphabetical domains, and suggest the existence of domain general, potentially ordinal, comparison processes supported by the left intraparietal sulcus.
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On the face of it, memory, imagination, and prediction seem to be distinct cognitive functions. However, metacognitive, cognitive, neuropsychological, and neuroimaging evidence is emerging that they are not, suggesting intimate links in their underlying processes. Here, we explore these empirical findings and the evolving theoretical frameworks that seek to explain how a common neural system supports our recollection of times past, imagination, and our attempts to predict the future.
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The ability to mentally simulate hypothetical scenarios is a rapidly growing area of research in both psychology and neuroscience. Episodic future thought, or the ability to simulate specific personal episodes that may potentially occur in the future, represents one facet of this general capacity that continues to garner a considerable amount of interest. The purpose of this article is to elucidate current knowledge and identify a number of unresolved issues regarding this specific mental ability. In particular, this article focuses on recent research findings from neuroimaging, neuropsychology, and clinical psychology that have demonstrated a close relation between episodic future thought and the ability to remember personal episodes from one's past. On the other hand, considerations of the role of abstracted (semantic) representations in episodic future thought have been noticeably absent in the literature. The final section of this article proposes that both episodic and semantic memory play an important role in the construction of episodic future thoughts and that their interaction in this process may be determined by the relative accessibility of information in memory. © The Author(s) 2010.
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Ingvar (1979, p. 21) theorized that memory plays a key role in allowing individuals to construct “alternative hypothetical behavior patterns in order to be ready for what may happen,” a process that he characterized as a “simulation of behavior”. Several years later, Ingvar elaborated these ideas by observing that “concepts about the future, like memories of past events, can be remembered, often in great detail” (Ingvar, 1985, p. 128), and that such “memories of the future” may offer important insights into the adaptive nature of human cognition. For instance, although the ability to simulate alternative versions of the future can benefit behavior, at least part of the adaptive advantage of future thinking may depend on the ability to remember the contents of simulated events (for discussion, see Suddendorf and Corballis, 1997, 2007; Szpunar, 2010; Schacter, 2012; Schacter et al., 2012). As an example, enlisting mental simulations of the future to help determine the best approach for resolving a conflict at home or in the workplace may confer few advantages if the outcome of the simulation process is not remembered at the time the simulated behavior is executed. Although much research exists concerning prospective memory – remembering to carry out future intentions (e.g., Kliegel et al., 2008; see also Brewer and Marsh, 2009) – there is a striking lack of evidence concerning “memory of the future” in the sense discussed by Ingvar, that is, memory for the contents of future simulations. Recently, however, several studies have provided the first glimpses into how well people remember details associated with simulated future events. In particular, these studies have demonstrated (1) enhanced memory for event details that are encoded with the future in mind, (2) factors that may influence the retention of simulated future events over extended time periods, and (3) neural correlates associated with encoding simulated future events. Next, we provide a brief overview of this emerging line of research, underscore the significance of various findings along with suggestions for future research directions, and conclude by discussing the relevance of this work to the concept of episodic memory. As we expand on below, it is our opinion that these new studies represent not only a useful extension of Ingvar's (1979, 1985) seminal observations, but that they also offer novel insights into the adaptive value of episodic memory.
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How can functional magnetic resonance imaging (fMRI) advance cognitive theory? Some have argued that fMRI can do little beyond localizing brain regions that carry out certain cognitive functions (and may not even be able to do that). However, in this article, we argue that fMRI can inform theories of cognition by helping to answer at least four distinct kinds of questions. Which mental functions are performed in brain regions specialized for just that function (and which are performed in more general-purpose brain machinery)? When fMRI markers of a particular Mental Process X are found, is Mental Process X engaged when people perform Task Y? How distinct are the representations of different stimulus classes? Do specific pairs of tasks engage common or distinct processing mechanisms? Thus, fMRI data can be used to address theoretical debates that have nothing to do with where in the brain a particular process is carried out.
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While humans are capable of mentally transcending the here and now, this faculty for mental time travel (MTT) is dependent upon an underlying cognitive representation of time. To this end, linguistic, cognitive and behavioral evidence has revealed that people understand abstract temporal constructs by mapping them to concrete spatial domains (e.g. past = backward, future = forward). However, very little research has investigated factors that may determine the topographical characteristics of these spatiotemporal maps. Guided by the imperative role of episodic content for retrospective and prospective thought (i.e., MTT), here we explored the possibility that the spatialization of time is influenced by the amount of episodic detail a temporal unit contains. In two experiments, participants mapped temporal events along mediolateral (Experiment 1) and anterioposterior (Experiment 2) spatial planes. Importantly, the temporal units varied in self-relevance as they pertained to temporally proximal or distal events in the participant's own life, the life of a best friend or the life of an unfamiliar other. Converging evidence from both experiments revealed that the amount of space used to represent time varied as a function of target (self, best friend or unfamiliar other) and temporal distance. Specifically, self-time was represented as occupying more space than time pertaining to other targets, but only for temporally proximal events. These results demonstrate the malleability of space-time mapping and suggest that there is a self-specific conceptualization of time that may influence MTT as well as other temporally relevant cognitive phenomena.
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Memory serves critical functions in everyday life but is also prone to error. This article examines adaptive constructive processes, which play a functional role in memory and cognition but can also produce distortions, errors, and illusions. The article describes several types of memory errors that are produced by adaptive constructive processes and focuses in particular on the process of imagining or simulating events that might occur in one's personal future. Simulating future events relies on many of the same cognitive and neural processes as remembering past events, which may help to explain why imagination and memory can be easily confused. The article considers both pitfalls and adaptive aspects of future event simulation in the context of research on planning, prediction, problem solving, mind-wandering, prospective and retrospective memory, coping and positivity bias, and the interconnected set of brain regions known as the default network. (PsycINFO Database Record (c) 2012 APA, all rights reserved).
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Despite the growing interest in future-oriented cognition in various areas of psychology, there is still little empirical data regarding the occurrence and nature of future-oriented thoughts in daily life. In this study, participants recorded future-oriented thoughts occurring in natural settings and rated their characteristics and functions. The results show that future-oriented thoughts occur frequently in daily life and can take different representational formats (more or less abstract), embrace various thematic contents (e.g. work, relationships) and serve a range of functions (e.g. action planning, decision making). The functions and characteristics of thoughts differed according to their temporal distance, with thoughts referring to the near future being more specific and serving action planning to a greater extent than thoughts concerning the far future. The characteristics of future thoughts were also related to affective content, with positive thoughts being more frequent, more specific, and associated with more visual images than negative thoughts. Copyright © 2009 John Wiley & Sons, Ltd.
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Spatial imagery refers to the inspection and evaluation of spatial features (e.g., distance, relative position, configuration) and/or the spatial manipulation (e.g., rotation, shifting, reorienting) of mentally generated visual images. In the past few decades, psychophysical as well as functional brain imaging studies have indicated that any such processing of spatially coded information and/or manipulation based on mental images (i) is subject to similar behavioral demands and limitations as in the case of spatial processing based on real visual images, and (ii) consistently activates several nodes of widely distributed cortical networks in the brain. These nodes include areas within both, the dorsal fronto-parietal as well as ventral occipito-temporal visual processing pathway, representing the "what" versus "where" aspects of spatial imagery. We here describe evidence from functional brain imaging and brain interference studies indicating systematic hemispheric differences within the dorsal fronto-parietal networks during the execution of spatial imagery. Importantly, such hemispheric differences and functional lateralization principles are also found in the effective brain network connectivity within and across these networks, with a direction of information flow from anterior frontal/premotor regions to posterior parietal cortices. In an attempt to integrate these findings of hemispheric lateralization and fronto-to-parietal interactions, we argue that spatial imagery constitutes a multifaceted cognitive construct that can be segregated in several distinct mental sub processes, each associated with activity within specific lateralized fronto-parietal (sub) networks, forming the basis of the here proposed dynamic network model of spatial imagery.
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Recent findings suggest that multiple event properties contribute to shape the phenomenology of episodic future thoughts, but the specific role of each property is not yet fully understood. This study shows that different phenomenological features are predicted by distinct event properties. The vividness of an episodic future thought largely depends on the familiarity of its constitutive elements (i.e., the envisioned location, persons and objects), while the visual perspective adopted is instead related to the temporal distance of the imagined event. Cognitive feelings such as the sense of pre-experiencing the future depend on sensory-perceptual qualities, and are further modulated by the personal importance attributed to the event. These findings suggest that the essence of episodic future thought-the sensation of mentally visiting one's personal future-lies, in part, in the relevance of imagined events with respect to personal goals.
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Investigations of the recovery and falsification of childhood memories have used one construct in lieu of another. Autobiographical memories have typically not been distinguished from autobiographical beliefs, and researchers have assumed that plausibility and schematic knowledge measure identical constructs. We tested the hypothesis that plausibility, autobiographical belief, and autobiographical memory are nested constructs, such that memory implies belief and belief implies plausibility. Six hundred and eighty five students answered questions about these constructs in relation to ten possible childhood events. Analysis of item means, response probabilities and the frequency with which items followed the predicted order demonstrated that the predicted pattern was upheld in over 95% of cases. Results did not support the hypothesis that plausibility and script knowledge are significantly related. Copyright © 2004 John Wiley & Sons, Ltd.
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There are logical and empirical grounds that link episodic memory and the ability to imagine future events. In some sense, both episodic memory and episodic foresight may be regarded as two sides of the same capacity to travel mentally in time. After reviewing some of the recent evidence for commonalities, I discuss limits of these parallels. There are fundamental differences between thinking about past and future events that need to be kept in clear view if we are to make progress in understanding the nature of mental time travel. The reviewed evidence suggests that mental time travel is based on a complex system selected not for accuracy about past and future per se, but for fitness benefits. Functional analyses promise to lead to fruitful avenues for future research. Copyright © 2009 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website. Copyright © 2009 John Wiley & Sons, Inc.
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The self has been the topic of philosophical inquiry for centuries. Neuropsychological data suggest that the declarative self can be fractionated into three functionally independent systems processing personal information at several levels of abstraction, including episodic memories of one's own life (episodic autobiographical memory, EAM), semantic knowledge of facts about one's own life (semantic autobiographical memory, SAM), and semantic summary representations of one's personal identity (conceptual self, CS). Our proposal here was to present a comprehensive description of the neural networks underpinning self-representations. To this aim, we performed three meta-analyses, one each for EAM, SAM, and CS, using the activation likelihood estimation (ALE) method. We expected a shift from posterior to anterior structures associated with the incrementally increasing level of abstraction of self-representations. The key finding was that EAM predominantly activates posterior and limbic regions including hippocampus. SAM is associated with anterior activations and also posterior and limbic activations in a lesser degree than EAM. CS mainly recruits medial prefrontal structures. Interestingly, medial prefrontal cortex is activated irrespective of the level of abstraction, but a more caudal part is recruited during CS, while SAM and EAM activate more rostral portions. To conclude, in line with the previous proposals, our results corroborate the idea that the declarative self is not monolithic but a multidimensional construct comprising distinct representations at different levels of abstraction. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
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Two functionally distinct, and potentially competing, brain networks have been recently identified that can be broadly distinguished by their contrasting roles in attention to the external world versus internally directed mentation involving long-term memory. At the core of these two networks are the dorsal attention system and the hippocampal-cortical memory system, a component of the brain's default network. Here spontaneous blood-oxygenation-level-dependent (BOLD) signal correlations were used in three separate functional magnetic resonance imaging data sets (n = 105) to define a third system, the frontoparietal control system, which is spatially interposed between these two previously defined systems. The frontoparietal control system includes many regions identified as supporting cognitive control and decision-making processes including lateral prefrontal cortex, anterior cingulate cortex, and inferior parietal lobule. Detailed analysis of frontal and parietal cortex, including use of high-resolution data, revealed clear evidence for contiguous but distinct regions: in general, the regions associated with the frontoparietal control system are situated between components of the dorsal attention and hippocampal-cortical memory systems. The frontoparietal control system is therefore anatomically positioned to integrate information from these two opposing brain systems.
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"Mental time travel" refers to conscious experience of remembering the personal past and imagining the personal future. Little is known about its neural correlates. Here, using functional magnetic resonance imaging, we explored the hypothesis that mental time travel into "nonpresent" times (past and future) is enabled by a special conscious state (chronesthesia). Well-trained subjects repeatedly imagined taking one and the same short walk in a familiar environment, doing so either in the imagined past, present, or future. In an additional condition, they recollected an instance in which they actually performed the same short walk in the same familiar setting. This design allowed us to measure brain activity correlated with "pure" conscious states of different moments of subjective time. The results showed that the left lateral parietal cortex was differentially activated by nonpresent subjective times compared with the present (past and future > present). A similar pattern was observed in the left frontal cortex, cerebellum, and thalamus. There was no evidence that the hippocampal region is involved in subjective time travel. These findings provide support for theoretical ideas concerning chronesthesia and mental time travel.
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One of the most consistent observations in human functional imaging is that a network of brain regions referred to as the "default network" increases its activity during passive states. Here we explored the anatomy and function of the default network across three studies to resolve divergent hypotheses about its contributions to spontaneous cognition and active forms of decision making. Analysis of intrinsic activity revealed the network comprises multiple, dissociated components. A midline core (posterior cingulate and anterior medial prefrontal cortex) is active when people make self-relevant, affective decisions. In contrast, a medial temporal lobe subsystem becomes engaged when decisions involve constructing a mental scene based on memory. During certain experimentally directed and spontaneous acts of future-oriented thought, these dissociated components are simultaneously engaged, presumably to facilitate construction of mental models of personally significant events.
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Reliving past events and imagining potential future events engages a well-established "core" network of brain areas. How the brain constructs, or reconstructs, these experiences or scenes has been debated extensively in the literature, but remains poorly understood. Here we designed a novel task to investigate this (re)constructive process by directly exploring how naturalistic scenes are built up from their individual elements. We "slowed-down" the construction process through the use of auditorily presented phrases describing single scene elements in a serial manner. Participants were required to integrate these elements (ranging from three to six in number) together in their imagination to form a naturalistic scene. We identified three distinct sub-networks of brain areas, each with different fMRI BOLD response profiles, favouring specific points in the scene construction process. Areas including the hippocampus and retrosplenial cortex had a biphasic profile, activating when a single scene element was imagined and when 3 elements were combined together; regions including the intra-parietal sulcus and angular gyrus steadily increased activity from 1 to 3 elements; while activity in areas such as lateral prefrontal cortex was observed from the second element onwards. Activity in these sub-networks did not increase further when integrating more than three elements. Participants confirmed that three elements were sufficient to construct a coherent and vivid scene, and once this was achieved, the addition of further elements only involved maintenance or small changes to that established scene. This task offers a potentially useful tool for breaking down scene construction, a process that may be key to a range of cognitive functions such as episodic memory, future thinking and navigation.
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Laboratory and autobiographical studies of normal adults' memory for the time of past events are reviewed, and the main phenomena that have been discovered are described. A distinction is introduced among several kinds of information on which this knowledge could be based: information about distances, locations, and relative times of occurrence. The main theories of memory for time are classified in these terms, and each theory is evaluated in light of the available evidence. In spite of the common intuition that chronology is a basic property of autobiographical memory, the research reviewed demonstrates that there is no single, natural temporal code in human memory Instead, a chronological past depends on a process of active, repeated construction.
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In the original publication of this manuscript, the name of the first author of reference [15] is incorrectly listed in the main text (p. 82) as ‘Templeton’. The correct surname for the first author of this publication is Templer.
Research on future-oriented mental time travel (FMTT) is highly active yet somewhat unruly. I believe this is due, in large part, to the complexity of both the tasks used to test FMTT and the concepts involved. Extraordinary care is a necessity when grappling with such complex and perplexing metaphysical constructs as self and time and their co-instantiation in memory. In this review, I first discuss the relation between future mental time travel and types of memory (episodic and semantic). I then examine the nature of both the types of self-knowledge assumed to be projected into the future and the types of temporalities that constitute projective temporal experience. Finally, I argue that a person lacking episodic memory should nonetheless be able to imagine a personal future by virtue of (1) the fact that semantic, as well as episodic, memory can be self-referential, (2) autonoetic awareness is not a prerequisite for FMTT, and (3) semantic memory does, in fact, enable certain forms of personally oriented FMTT. WIREs Cogn Sci 2013, 4:63-79. doi: 10.1002/wcs.1210 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.
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We spend much of our daily lives imagining how we can reach future goals and what will happen when we attain them. Despite the prevalence of such goal-directed simulations, neuroimaging studies on planning have mainly focused on executive processes in the frontal lobe. This experiment examined the neural basis of process simulations, during which participants imagined themselves going through steps toward attaining a goal, and outcome simulations, during which participants imagined events they associated with achieving a goal. In the scanner, participants engaged in these simulation tasks and an odd/even control task. We hypothesized that process simulations would recruit default and frontoparietal control network regions, and that outcome simulations, which allow us to anticipate the affective consequences of achieving goals, would recruit default and reward-processing regions. Our analysis of brain activity that covaried with process and outcome simulations confirmed these hypotheses. A functional connectivity analysis with posterior cingulate, dorsolateral prefrontal cortex, and anterior inferior parietal lobule seeds showed that their activity was correlated during process simulations and associated with a distributed network of default and frontoparietal control network regions. During outcome simulations, medial prefrontal cortex and amygdala seeds covaried together and formed a functional network with default and reward-processing regions.
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It has long been assumed that familiarity- and novelty-related processes fall on a single continuum drawing on the same cognitive and neural mechanisms. The possibility that familiarity and novelty processing involve distinct neural networks was explored in a functional magnetic resonance imaging study (fMRI), in which familiarity and novelty judgments were made in contexts emphasizing either familiarity or novelty decisions. Parametrically modulated BOLD responses to familiarity and novelty strength were isolated in two separate, non-overlapping brain networks. The novelty system involved brain regions along the ventral visual stream, the hippocampus, and the perirhinal and parahippocampal cortices. The familiarity system, on the other hand, involved the dorsomedial thalamic nucleus, and regions within the medial prefrontal cortex and the medial and lateral parietal cortex. Convergence of the two networks, treating familiarity and novelty as a single continuum was only found in a fronto-parietal network. Finally, the orbitomedial prefrontal cortex was found to be sensitive to reported strength/confidence, irrespective of stimulus' familiarity or novelty. This pattern of results suggests a dual-route mechanism supported by the existence of two distinct but interacting functional systems for familiarity and novelty. Overall, these findings challenge current assumptions regarding the neural systems that support the processing of novel and familiar information, and have important implications for research into the neural bases of recognition memory. © 2014 Wiley Periodicals, Inc.
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Research on memory for the times of past events has revealed ten main phenomena that constrain theoretical accounts of time in autobiographical memory. These findings do not support a uniform time-tagging mechanism or a temporally organized memory store. Instead, a combination of processes, most notably the reconstruction of past times, underlies our chronological sense of the past. We are especially adept at remembering "locations" in the many temporal patterns that structure our lives, but some information about the order of related events, distances in the past, and specific dates is also available. These processes contribute to our sense of a personal past, a shared past in close relationships, and a coherent sense of the lives of other people.
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One characteristic of humans is that they have a sense of self. An examination of research and theory exploring the psychology of the self suggests that it has at least three important aspects. The first of these aspects is representation: the memory system contains mental structures that store and organize different kinds of selfrelevant knowledge. In addition, some of the knowledge reflects episodic memories of specific life events. These memories contain perceptual details of events, as well as information about event contexts. The second attribute of the human self is that it maintains an executive function, regulating an individual's relation with the social and physical environment. The third attribute of the self is reflexivity. This term can be defined as the organism's ability to depict itself in its ongoing relation with other objects.
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Everyday concepts of duration, of sequence, and of past, present, and future are fundamental to how humans make sense of experience. In culture after culture, converging evidence from language, co-speech gesture, and behavioral tasks suggests that humans handle these elusive yet indispensable notions by construing them spatially. Where do these spatial construals come from and why do they take the particular, sometimes peculiar, spatial forms that they do? As researchers across the cognitive sciences pursue these questions on different levels - cultural, developmental - in diverse populations and with new methodologies, clear answers will depend upon a shared and nuanced set of theoretical distinctions. Time is not a monolith, but rather a mosaic of construals with distinct properties and origins.
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Investigation of the hippocampus has historically focused on computations within the trisynaptic circuit. However, discovery of important anatomical and functional variability along its long axis has inspired recent proposals of long-axis functional specialization in both the animal and human literatures. Here, we review and evaluate these proposals. We suggest that various long-axis specializations arise out of differences between the anterior (aHPC) and posterior hippocampus (pHPC) in large-scale network connectivity, the organization of entorhinal grid cells, and subfield compositions that bias the aHPC and pHPC towards pattern completion and separation, respectively. The latter two differences give rise to a property, reflected in the expression of multiple other functional specializations, of coarse, global representations in anterior hippocampus and fine-grained, local representations in posterior hippocampus.
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A fundamental question in cognitive neuroscience is how the human brain self-organizes to perform tasks. Multiple accounts of this self-organization are currently influential and in this article we survey one of these accounts. We begin by introducing a psychological model of task control and several neuroimaging signals it predicts. We then discuss where such signals are found across tasks with emphasis on brain regions where multiple control signals are present. We then present results derived from spontaneous task-free functional connectivity between control-related regions that dovetail with distinctions made by control signals present in these regions, leading to a proposal that there are at least two task control systems in the brain. This prompts consideration of whether and how such control systems distinguish themselves from other brain regions in a whole-brain context. We present evidence from whole-brain networks that such distinctions do occur and that control systems comprise some of the basic system-level organizational elements of the human brain. We close with observations from the whole-brain networks that may suggest parsimony between multiple accounts of cognitive control.
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Considerable recent work has shown that the hippocampus is critical for remembering the order of events in distinct experiences, a defining feature of episodic memory. Correspondingly, hippocampal neuronal activity can 'replay' sequential events in memories and hippocampal neuronal ensembles represent a gradually changing temporal context signal. Most strikingly, single hippocampal neurons - called time cells - encode moments in temporally structured experiences much as the well-known place cells encode locations in spatially structured experiences. These observations bridge largely disconnected literatures on the role of the hippocampus in episodic memory and spatial mapping, and suggest that the fundamental function of the hippocampus is to establish spatio-temporal frameworks for organizing memories.
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During the past few years, there has been a dramatic increase in research examining the role of memory in imagination and future thinking. This work has revealed striking similarities between remembering the past and imagining or simulating the future, including the finding that a common brain network underlies both memory and imagination. Here, we discuss a number of key points that have emerged during recent years, focusing in particular on the importance of distinguishing between temporal and nontemporal factors in analyses of memory and imagination, the nature of differences between remembering the past and imagining the future, the identification of component processes that comprise the default network supporting memory-based simulations, and the finding that this network can couple flexibly with other networks to support complex goal-directed simulations. This growing area of research has broadened our conception of memory by highlighting the many ways in which memory supports adaptive functioning.
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29 undergraduates carrying a beeper for 7 days described properties of their consciousness on a total of 1,425 occasions by means of a thought-sampling questionnaire, anxiety and depression measures, and activity report forms. Intra-S analyses of thought variables identified 8 orthogonal factors: Visual Modality, Auditory Modality, Operantness, Attentiveness to External Stimulation, Controllability, Strangeness, Past Time Orientation, and Future Time Orientation. Most thought samples contained some interior monologue largely independent of other variables. The visual modality predominated for most individuals. Approximately one-third of thought was predominantly undirected, one-third was stimulus-independent, and about one-quarter contained at least traces of dream-like elements. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Laboratory and autobiographical studies of normal adults' memory for the time of past events are reviewed, and the main phenomena that have been discovered are described. A distinction is introduced among several kinds of information on which this knowledge could be based: information about distances, locations, and relative times of occurrence. The main theories of memory for time are classified in these terms, and each theory is evaluated in light of the available evidence. In spite of the common intuition that chronology is a basic property of autobiographical memory, the research reviewed demonstrates that there is no single, natural temporal code in human memory. Instead, a chronological past depends on a process of active, repeated construction. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
The ability to think about the future-prospection-is central to many aspects of human cognition and behavior, from planning and decision making, to self-control and the construction of a sense of identity. Yet, the exact nature of the representational systems underlying prospection is not fully understood. Recent findings point to the critical role of episodic memory in imagining specific future events, but it is unlikely that prospection depends solely on this system. Using an event-cueing paradigm in two studies, we here show that specific events that people imagine might happen in their personal future are commonly embedded in broader event sequences-termed event clusters-that link a set of envisioned events according to causal and thematic relations. These findings provide novel evidence that prospection relies on multiple representational systems, with general autobiographical knowledge structures providing a frame that organizes imagined events in overarching event sequences. The results further suggest that knowledge about personal goals plays an important role in structuring these event sequences, especially for the distant future.
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In designing experiments to investigate retrieval of event memory, researchers choose between utilizing laboratory-based methods (in which to-be-remembered materials are presented to participants) and autobiographical approaches (in which the to-be-remembered materials are events from the participant's pre-experimental life). In practice, most laboratory studies have utilized old/new recognition memory, and most autobiographical memory studies have used the Galton–Crovitz word cueing technique [Crovitz, H.F., & Schiffman, H. (1974). Frequency of episodic memories as a function of their age. Bulletin of the Psychonomic Society, 4, 517–518]. What are the implications of these methodological choices for understanding the component processes and underlying neural substrates of memory retrieval? An Activation Likelihood Estimation (ALE) meta-analysis procedure [Turkeltaub, P., Eden, G., Jones, K., & Zeffiro, TA. (2002). Meta-analysis of the functional neuroanatomy of single-word reading: Method and validation. NeuroImage, 16, 765–780] was used to construct two whole-brain statistical maps: one showing brain regions that are consistently implicated when the task utilized is old/new recognition memory and one showing regions that tend to emerge when autobiographical event memory is queried. A comparison of the two maps shows very few regions of overlap. This basic methodological choice has a profound impact on the conclusions reached regarding human memory retrieval and its neural substrates.
Article
In this paper, we discuss the construct of episodic future thinking. We have previously defined episodic future thinking as the ability to project oneself into the future to pre-experience an event (Atance & O’Neill, 2001). We distinguish this type of thinking about the future from that which is largely based on a script of how an event routinely unfolds (e.g., a restaurant or birthday party script). This distinction is related to the episodic/semantic distinction that has been applied to memory (Tulving, 1972). We discuss tasks, both verbal and nonverbal, that we have developed for young children, and that we believe assess episodic future thinking. Based on our findings from these tasks, we conclude that episodic future thinking emerges between 3 and 4 years of age. Throughout the paper, we attempt to specify the nature of the projection associated with episodic future thinking by elaborating upon how children’s behavior in the tasks we discuss, as well as their behaviors in other contexts, are a reflection of this projection.
Article
A crucial aspect of the human mind is the ability to project the self along the time line to past and future. It has been argued that such self-projection is essential to re-experience past experiences and predict future events. In-depth analysis of a novel paradigm investigating mental time shows that the speed of this “self-projection” in time depends logarithmically on the temporal-distance between an imagined “location” on the time line that participants were asked to imagine and the location of another imagined event from the time line. This logarithmic pattern suggests that events in human cognition are spatially mapped along an imagery mental time line. We argue that the present time-line data are comparable to the spatial mapping of numbers along the mental number line and that such spatial maps are a fundamental basis for cognition.
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Mental time travel in human adults includes a sense of when past events occurred and future events are expected to occur. Studies with adults and children reveal that a number of distinct psychological processes contribute to a temporally differentiated sense of the past and future. Adults possess representations of multiple time patterns, and these representations take several different forms. Memory for the times of past events is built upon reconstruction of temporal locations, impressions of distances in the past, and order-codes. The times of future events are understood primarily as locations in represented time patterns, but propositions active in memory contain information that particular events are coming soon. Young children have difficulty distinguishing the past–future status of some events, showing that basic memory processes do not make the distinction clear. Concepts of the past and future may be required for differentiating these two categories of experience.
Article
Most internally oriented mental activities are known to strongly activate the default network, which includes remembering the past, future thinking and social cognition, and are heavily self-referential, and demanding of memory retrieval processes. Based on these observations and building on related findings from the literature, the present article proposed a simple, dual-subsystem model of the default network. The ability of the model to estimate brain activity during autobiographical memory (AM) retrieval and related reference conditions was then tested by performing a quantitative meta-analysis of relevant literature. The model divided the default network into two subsystems. The first, called the 'cortical midline subsystem (CMS)', was comprised of the anteromedial prefrontal cortex and posterior cingulate cortex, and primarily mediates self-referential processing. The other, termed the 'parieto-temporal subsystem (PTS)', included the inferior parietal lobule, medial temporal lobe and lateral temporal cortex, and mainly supports memory retrieval processes. The meta-analysis of AM retrieval contrasts yielded a double dissociation that was consistent with this model. First, CMS regions associated more with an AM>laboratory-based memory (LM) contrast than with an AM>rest contrast, confirming that these regions play more critical roles in self-referential processing than memory retrieval processes. Second, all three PTS regions showed a greater association with an AM>rest contrast than with an AM>LM contrast, confirming that their role in memory retrieval processes is greater than in self-referential processing. Although the present model is limited in scope, both in terms of anatomical and functional specifications, it integrates diverse processes such as self-referential processing, episodic and semantic memory and subsystem interface, and provides useful heuristics that can guide further research on fractionation of the default network.
Article
We investigated the contributions of familiarity of setting, self-relevance and self-projection in time to episodic future thinking. The role of familiarity of setting was assessed, in Experiment 1, by comparing episodic future thoughts to autobiographical future events supposed to occur in unfamiliar settings. The role of self-relevance was assessed, in Experiment 2, by comparing episodic future thoughts to future events involving familiar others. The role of self-projection in time was assessed, in both Experiments, by comparing episodic future thoughts to autobiographical events that were not temporal in nature. Results indicated that episodic future thoughts were more clearly represented than autobiographical future events occurring in unfamiliar setting and future events involving familiar others. Our results also revealed that episodic future thoughts were indistinguishable from autobiographical atemporal events with respect to both subjective and objective detail ratings. These results suggest that future and atemporal events are mentally represented in a similar way.
Article
Precuneus responds to a wide range of cognitive processes. Here, we examined how the patterns of resting state connectivity may define functional subregions in the precuneus. Using a K-means algorithm to cluster the whole-brain "correlograms" of the precuneus in 225 adult individuals, we corroborated the dorsal-anterior, dorsal-posterior, and ventral subregions, each involved in spatially guided behaviors, mental imagery, and episodic memory as well as self-related processing, with the ventral precuneus being part of the default mode network, as described extensively in earlier work. Furthermore, we showed that the lateral/medial volumes of dorsal anterior and dorsal posterior precuneus are each connected with areas of motor execution/attention and motor/visual imagery, respectively. Compared to the ventral precuneus, the dorsal precuneus showed greater connectivity with occipital and posterior parietal cortices, but less connectivity with the medial superior frontal and orbitofrontal gyri, anterior cingulate cortex as well as the parahippocampus. Compared to dorsal-posterior and ventral precuneus, the dorsal-anterior precuneus showed greater connectivity with the somatomotor cortex, as well as the insula, supramarginal, Heschl's, and superior temporal gyri, but less connectivity with the angular gyrus. Compared to ventral and dorsal-anterior precuneus, dorsal-posterior precuneus showed greater connectivity with the middle frontal gyrus. Notably, the precuneus as a whole has negative connectivity with the amygdala and the lateral and inferior orbital frontal gyri. Finally, men and women differed in the connectivity of precuneus. Men and women each showed greater connectivity with the dorsal precuneus in the cuneus and medial thalamus, respectively. Women also showed greater connectivity with ventral precuneus in the hippocampus/parahippocampus, middle/anterior cingulate gyrus, and middle occipital gyrus, compared to men. Taken together, these new findings may provide a useful platform upon which to further investigate sex-specific functional neuroanatomy of the precuneus and to elucidate the pathology of many neurological illnesses.
Article
Episodic memory is widely conceived as a fundamentally constructive, rather than reproductive, process that is prone to various kinds of errors and illusions. With a view towards examining the functions served by a constructive episodic memory system, we consider recent neuropsychological and neuroimaging studies indicating that some types of memory distortions reflect the operation of adaptive processes. An important function of a constructive episodic memory is to allow individuals to simulate or imagine future episodes, happenings and scenarios. Since the future is not an exact repetition of the past, simulation of future episodes requires a system that can draw on the past in a manner that flexibly extracts and recombines elements of previous experiences. Consistent with this constructive episodic simulation hypothesis, we consider cognitive, neuropsychological and neuroimaging evidence showing that there is considerable overlap in the psychological and neural processes involved in remembering the past and imagining the future.
Article
Perhaps one of the most remarkable, and under appreciated, achievements of the human brain is our capacity to be aware of the subjective time in which we exist. Although we do not think much about this sense of time, we make use of it whenever we remember something that happened to us in the past or imagine something that might happen to us in the future. In what follows, I (i) define subjective time, (ii) explicate how we might begin to understand the capacity to be aware of subjective time, also known as “chronesthesia” [a concept whose name is derived from the Greek words Chronos (time) and Aisthesis (to feel) (Tulving, 2002)], and (iii) speculate about the relation of subjective time to the human brain.
Article
Tasks that demand externalized attention reliably suppress default network activity while activating the dorsal attention network. These networks have an intrinsic competitive relationship; activation of one suppresses activity of the other. Consequently, many assume that default network activity is suppressed during goal-directed cognition. We challenge this assumption in an fMRI study of planning. Recent studies link default network activity with internally focused cognition, such as imagining personal future events, suggesting a role in autobiographical planning. However, it is unclear how goal-directed cognition with an internal focus is mediated by these opposing networks. A third anatomically interposed 'frontoparietal control network' might mediate planning across domains, flexibly coupling with either the default or dorsal attention network in support of internally versus externally focused goal-directed cognition, respectively. We tested this hypothesis by analyzing brain activity during autobiographical versus visuospatial planning. Autobiographical planning engaged the default network, whereas visuospatial planning engaged the dorsal attention network, consistent with the anti-correlated domains of internalized and externalized cognition. Critically, both planning tasks engaged the frontoparietal control network. Task-related activation of these three networks was anatomically consistent with independently defined resting-state functional connectivity MRI maps. Task-related functional connectivity analyses demonstrate that the default network can be involved in goal-directed cognition when its activity is coupled with the frontoparietal control network. Additionally, the frontoparietal control network may flexibly couple with the default and dorsal attention networks according to task domain, serving as a cortical mediator linking the two networks in support of goal-directed cognitive processes.
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