51
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Robin J, Rai Y, Valli M, Olsen RK. Category specificity in the medial temporal lobe: A systematic review. Hippocampus 2018; 29:313-339. [PMID: 30155943 DOI: 10.1002/hipo.23024] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 08/03/2018] [Accepted: 08/07/2018] [Indexed: 01/30/2023]
Abstract
Theoretical accounts of medial temporal lobe (MTL) function ascribe different functions to subregions of the MTL including perirhinal, entorhinal, parahippocampal cortices, and the hippocampus. Some have suggested that the functional roles of these subregions vary in terms of their category specificity, showing preferential coding for certain stimulus types, but the evidence for this functional organization is mixed. In this systematic review, we evaluate existing evidence for regional specialization in the MTL for three categories of visual stimuli: faces, objects, and scenes. We review and synthesize across univariate and multivariate neuroimaging studies, as well as neuropsychological studies of cases with lesions to the MTL. Neuroimaging evidence suggests that faces activate the perirhinal cortex, entorhinal cortex, and the anterior hippocampus, while scenes engage the parahippocampal cortex and both the anterior and posterior hippocampus, depending on the contrast condition. There is some evidence for object-related activity in anterior MTL regions when compared to scenes, and in posterior MTL regions when compared to faces, suggesting that aspects of object representations may share similarities with face and scene representations. While neuroimaging evidence suggests some hippocampal specialization for faces and scenes, neuropsychological evidence shows that hippocampal damage leads to impairments in scene memory and perception, but does not entail equivalent impairments for faces in cases where the perirhinal cortex remains intact. Regional specialization based on stimulus categories has implications for understanding the mechanisms of MTL subregions, and highlights the need for the development of theoretical models of MTL function that can accommodate the differential patterns of specificity observed in the MTL.
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Affiliation(s)
- Jessica Robin
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada
| | - Yeshith Rai
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada
| | - Mikaeel Valli
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Rosanna K Olsen
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada.,Department of Psychology, University of Toronto, Toronto, Ontario, Canada
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52
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Rolls ET, Wirth S. Spatial representations in the primate hippocampus, and their functions in memory and navigation. Prog Neurobiol 2018; 171:90-113. [DOI: 10.1016/j.pneurobio.2018.09.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 09/10/2018] [Accepted: 09/10/2018] [Indexed: 01/01/2023]
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53
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Zhou W, Chen H, Yang J. Discriminative learning of similar objects enhances memory for the objects and contexts. ACTA ACUST UNITED AC 2018; 25:601-610. [PMID: 30442768 PMCID: PMC6239131 DOI: 10.1101/lm.047514.118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 09/11/2018] [Indexed: 11/25/2022]
Abstract
How to improve our episodic memory is an important issue in the field of memory. In the present study, we used a discriminative learning paradigm that was similar to a paradigm used in animal studies. In Experiment 1, a picture (e.g., a dog) was either paired with an identical picture, with a similar picture of the same concept (e.g., another dog), or with a picture of a different concept (e.g., a cat). Then, after intervals of 10 min, 1 d, and 1 wk, participants were asked to perform a 2-alternative forced-choice (2AFC) task to discriminate between a repeated and a similar picture, followed by the contextual judgment. In Experiment 2, eye movements were measured when participants encoded the pairs of pictures. The results showed that by discriminative learning, there was better memory performance in the 2AFC task for the “same” and “similar” conditions than for the “different” condition. In addition, there was better contextual memory performance for the “similar” condition than for the other two conditions. With regard to the eye movements, the participants were more likely to fixate on the lure objects and made more saccades between the target and lure objects in the “similar” (versus “different”) condition. The number of saccades predicted how well the targets were remembered in both the 2AFC and contextual memory tasks. These results suggested that with discriminative learning of similar objects, detailed information could be better encoded by distinguishing the object from similar interferences, making the details and the contexts better remembered and retained over time.
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Affiliation(s)
- Wenxi Zhou
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, 100871, China
| | - Haoyu Chen
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, 100871, China
| | - Jiongjiong Yang
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, 100871, China
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54
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Lucas HD, Duff MC, Cohen NJ. The Hippocampus Promotes Effective Saccadic Information Gathering in Humans. J Cogn Neurosci 2018; 31:186-201. [PMID: 30188777 DOI: 10.1162/jocn_a_01336] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
It is well established that the hippocampus is critical for memory. Recent evidence suggests that one function of hippocampal memory processing is to optimize how people actively explore the world. Here we demonstrate that the link between the hippocampus and exploration extends even to the moment-to-moment use of eye movements during visuospatial memory encoding. In Experiment 1, we examined relationships between study-phase eye movements in healthy individuals and subsequent performance on a spatial reconstruction test. In addition to quantitative measures of viewing behaviors (e.g., how many fixations or saccades were deployed during study), we used the information-theoretic measure of entropy to assess the amount of randomness or disorganization in participants' scanning behaviors. We found that the use of scanpaths during study that were lower in entropy (e.g., more organized, less random) predicted more accurate spatial reconstruction both within and between participants. Scanpath entropy was a better predictor of reconstruction accuracy than were the quantitative measures of viewing. In Experiment 2, we found that individuals with hippocampal amnesia tended to engage in viewing patterns that were higher in entropy (less organized) relative to healthy comparisons. These findings reveal a critical role of the hippocampus in guiding eye movement exploration to optimize visuospatial relational memory.
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Affiliation(s)
- Heather D Lucas
- Louisiana State University.,University of Illinois Urbana-Champaign
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55
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Serotonin receptor 2c-expressing cells in the ventral CA1 control attention via innervation of the Edinger–Westphal nucleus. Nat Neurosci 2018; 21:1239-1250. [DOI: 10.1038/s41593-018-0207-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 06/24/2018] [Indexed: 11/09/2022]
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56
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Liu ZX, Shen K, Olsen RK, Ryan JD. Age-related changes in the relationship between visual exploration and hippocampal activity. Neuropsychologia 2018; 119:81-91. [PMID: 30075215 DOI: 10.1016/j.neuropsychologia.2018.07.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 07/23/2018] [Accepted: 07/30/2018] [Indexed: 10/28/2022]
Abstract
Deciphering the mechanisms underlying age-related memory declines remains an important goal in cognitive neuroscience. Recently, we observed that visual sampling behavior predicted activity within the hippocampus, a region critical for memory. In younger adults, increases in the number of gaze fixations were associated with increases in hippocampal activity (Liu et al., 2017). This finding suggests a close coupling between the oculomotor and memory system. However, the extent to which this coupling is altered with aging has not been investigated. In this study, we gave older adults the same face processing task used in Liu et al. (2017) and compared their visual exploration behavior and neural activation in the hippocampus and the fusiform face area (FFA) to those of younger adults. Compared to younger adults, older adults showed an increase in visual exploration as indexed by the number of gaze fixations. However, the relationship between visual exploration and neural responses in the hippocampus and FFA was weaker than that of younger adults. Older adults also showed weaker responses to novel faces and a smaller repetition suppression effect in the hippocampus and FFA compared to younger adults. All together, this study provides novel evidence that the capacity to bind visually sampled information, in real-time, into coherent representations along the ventral visual stream and the medial temporal lobe declines with aging.
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Affiliation(s)
- Zhong-Xu Liu
- Rotman Research Institute, Baycrest, Toronto, Ontario, Canada M6A 2E1.
| | - Kelly Shen
- Rotman Research Institute, Baycrest, Toronto, Ontario, Canada M6A 2E1
| | - Rosanna K Olsen
- Rotman Research Institute, Baycrest, Toronto, Ontario, Canada M6A 2E1; Department of Psychology, University of Toronto, Toronto, Ontario, Canada M5S 3G3
| | - Jennifer D Ryan
- Rotman Research Institute, Baycrest, Toronto, Ontario, Canada M6A 2E1; Department of Psychology, University of Toronto, Toronto, Ontario, Canada M5S 3G3; Department of Psychiatry, University of Toronto, Canada
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57
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Nau M, Julian JB, Doeller CF. How the Brain's Navigation System Shapes Our Visual Experience. Trends Cogn Sci 2018; 22:810-825. [PMID: 30031670 DOI: 10.1016/j.tics.2018.06.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/25/2018] [Accepted: 06/27/2018] [Indexed: 11/25/2022]
Abstract
We explore the environment not only by navigating, but also by viewing our surroundings with our eyes. Here we review growing evidence that the mammalian hippocampal formation, extensively studied in the context of navigation and memory, mediates a representation of visual space that is stably anchored to the external world. This visual representation puts the hippocampal formation in a central position to guide viewing behavior and to modulate visual processing beyond the medial temporal lobe (MTL). We suggest that vision and navigation share several key computational challenges that are solved by overlapping and potentially common neural systems, making vision an optimal domain to explore whether and how the MTL supports cognitive operations beyond navigation.
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Affiliation(s)
- Matthias Nau
- Kavli Institute for Systems Neuroscience, Centre for Neural Computation, The Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, NTNU, Norwegian University of Science and Technology, Trondheim, Norway; These authors contributed equally to this work
| | - Joshua B Julian
- Kavli Institute for Systems Neuroscience, Centre for Neural Computation, The Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, NTNU, Norwegian University of Science and Technology, Trondheim, Norway; These authors contributed equally to this work.
| | - Christian F Doeller
- Kavli Institute for Systems Neuroscience, Centre for Neural Computation, The Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, NTNU, Norwegian University of Science and Technology, Trondheim, Norway; Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands; St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway; Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
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58
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Saccades are phase-locked to alpha oscillations in the occipital and medial temporal lobe during successful memory encoding. PLoS Biol 2017; 15:e2003404. [PMID: 29267286 PMCID: PMC5766246 DOI: 10.1371/journal.pbio.2003404] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 01/12/2018] [Accepted: 12/04/2017] [Indexed: 11/19/2022] Open
Abstract
Efficient sampling of visual information requires a coordination of eye movements and ongoing brain oscillations. Using intracranial and magnetoencephalography (MEG) recordings, we show that saccades are locked to the phase of visual alpha oscillations and that this coordination is related to successful mnemonic encoding of visual scenes. Furthermore, parahippocampal and retrosplenial cortex involvement in this coordination reflects effective vision-to-memory mapping, highlighting the importance of neural oscillations for the interaction between visual and memory domains.
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59
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Lisman J, Buzsáki G, Eichenbaum H, Nadel L, Ranganath C, Redish AD. Viewpoints: how the hippocampus contributes to memory, navigation and cognition. Nat Neurosci 2017; 20:1434-1447. [PMID: 29073641 PMCID: PMC5943637 DOI: 10.1038/nn.4661] [Citation(s) in RCA: 387] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The hippocampus serves a critical function in memory, navigation, and cognition. Nature Neuroscience asked John Lisman to lead a group of researchers in a dialog on shared and distinct viewpoints on the hippocampus. There has been a long history of studying the hippocampus, but recent work has made it possible to study the cellular and network basis of defined operations—operations that include cognitive processes that have been otherwise difficult to study (see Box 1 for useful terminology). These operations deal with the context-dependent representation of complex memories, the role of mental exploration based on imagined rather than real movements, and the use of recalled information for navigation and decision-making. The progress that has been made in understanding the hippocampus has motivated the study of other brain regions that provide hippocampal input or receive hippocampal output; the hippocampus is thus serving as a nucleating point for the larger goal of understanding the neural codes that allow inter-regional communication and more generally, understanding how memory-guided behavior is achieved by large scale integration of brain regions. In generating a discussion among experts in the study of the cognitive processes of the hippocampus, the editors and I have posed questions that probe important principles of hippocampal function. We hope that the resulting discussion will make clear to readers the progress that has been made, while also identifying issues where consensus has not yet been achieved and that should be pursued in future research. – John Lisman
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Affiliation(s)
- John Lisman
- Department of Biology at Brandeis University, Waltham, Massachusetts, USA
| | - György Buzsáki
- NYU Neuroscience Institute at New York University, New York, New York, USA
| | - Howard Eichenbaum
- Center for Memory and Brain at Boston University, Boston, Massachusetts, USA
| | - Lynn Nadel
- Department of Psychology and Cognitive Science Program at University of Arizona, Tucson, Arizona, USA
| | - Charan Ranganath
- Center for Neuroscience and Department of Psychology at the University of California, Davis, California, USA
| | - A David Redish
- Department of Neuroscience at the University of Minnesota, Minneapolis, Minnesota, USA
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60
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Abstract
Current interpretations of hippocampal memory function are blind to the fact that viewing behaviors are pervasive and complicate the relationships among perception, behavior, memory, and brain activity. For example, hippocampal activity and associative memory demands increase with stimulus complexity. Stimulus complexity also strongly modulates viewing. Associative processing and viewing thus are often confounded, rendering interpretation of hippocampal activity ambiguous. Similar considerations challenge many accounts of hippocampal function. To explain relationships between memory and viewing, we propose that the hippocampus supports the online memory demands necessary to guide visual exploration. The hippocampus thus orchestrates memory-guided exploration that unfolds over time to build coherent memories. This new perspective on hippocampal function harmonizes with the fact that memory formation and exploratory viewing are tightly intertwined.
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61
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Voss JL, Cohen NJ. Hippocampal-cortical contributions to strategic exploration during perceptual discrimination. Hippocampus 2017; 27:642-652. [PMID: 28241401 DOI: 10.1002/hipo.22719] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 02/13/2017] [Accepted: 02/15/2017] [Indexed: 11/10/2022]
Abstract
The hippocampus is crucial for long-term memory; its involvement in short-term or immediate expressions of memory is more controversial. Rodent hippocampus has been implicated in an expression of memory that occurs on-line during exploration termed "vicarious trial-and-error" (VTE) behavior. VTE occurs when rodents iteratively explore options during perceptual discrimination or at choice points. It is strategic in that it accelerates learning and improves later memory. VTE has been associated with activity of rodent hippocampal neurons, and lesions of hippocampus disrupt VTE and associated learning and memory advantages. Analogous findings of VTE in humans would support the role of hippocampus in active use of short-term memory to guide strategic behavior. We therefore measured VTE using eye-movement tracking during perceptual discrimination and identified relevant neural correlates with functional magnetic resonance imaging. A difficult perceptual-discrimination task was used that required visual information to be maintained during a several second trial, but with no long-term memory component. VTE accelerated discrimination. Neural correlates of VTE included robust activity of hippocampus and activity of a network of medial prefrontal and lateral parietal regions involved in memory-guided behavior. This VTE-related activity was distinct from activity associated with simply viewing visual stimuli and making eye movements during the discrimination task, which occurred in regions frequently associated with visual processing and eye-movement control. Subjects were mostly unaware of performing VTE, thus further distancing VTE from explicit long-term memory processing. These findings bridge the rodent and human literatures on neural substrates of memory-guided behavior, and provide further support for the role of hippocampus and a hippocampal-centered network of cortical regions in the immediate use of memory in on-line processing and the guidance of behavior.
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Affiliation(s)
- Joel L Voss
- Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Neal J Cohen
- Department of Psychology and Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Champaign, Illinois
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