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Elliott BL, Mohyee RA, Ballard IC, Olson IR, Ellman LM, Murty VP. In vivo structural connectivity of the reward system along the hippocampal long axis. Hippocampus 2024; 34:327-341. [PMID: 38700259 DOI: 10.1002/hipo.23608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 03/11/2024] [Accepted: 04/18/2024] [Indexed: 05/05/2024]
Abstract
Recent work has identified a critical role for the hippocampus in reward-sensitive behaviors, including motivated memory, reinforcement learning, and decision-making. Animal histology and human functional neuroimaging have shown that brain regions involved in reward processing and motivation are more interconnected with the ventral/anterior hippocampus. However, direct evidence examining gradients of structural connectivity between reward regions and the hippocampus in humans is lacking. The present study used diffusion MRI (dMRI) and probabilistic tractography to quantify the structural connectivity of the hippocampus with key reward processing regions in vivo. Using a large sample of subjects (N = 628) from the human connectome dMRI data release, we found that connectivity profiles with the hippocampus varied widely between different regions of the reward circuit. While the dopaminergic midbrain (ventral tegmental area) showed stronger connectivity with the anterior versus posterior hippocampus, the ventromedial prefrontal cortex showed stronger connectivity with the posterior hippocampus. The limbic (ventral) striatum demonstrated a more homogeneous connectivity profile along the hippocampal long axis. This is the first study to generate a probabilistic atlas of the hippocampal structural connectivity with reward-related networks, which is essential to investigating how these circuits contribute to normative adaptive behavior and maladaptive behaviors in psychiatric illness. These findings describe nuanced structural connectivity that sets the foundation to better understand how the hippocampus influences reward-guided behavior in humans.
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Affiliation(s)
- Blake L Elliott
- Department of Psychology and Neuroscience, Temple University, Philadelphia, Pennsylvania, USA
| | - Raana A Mohyee
- Department of Psychology and Neuroscience, Temple University, Philadelphia, Pennsylvania, USA
| | - Ian C Ballard
- Department of Psychology, University of California, Riverside, California, USA
| | - Ingrid R Olson
- Department of Psychology and Neuroscience, Temple University, Philadelphia, Pennsylvania, USA
| | - Lauren M Ellman
- Department of Psychology and Neuroscience, Temple University, Philadelphia, Pennsylvania, USA
| | - Vishnu P Murty
- Department of Psychology and Neuroscience, Temple University, Philadelphia, Pennsylvania, USA
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2
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Hu Z, Yang J. Effects of memory cue and interest in remembering and forgetting of gist and details. Front Psychol 2023; 14:1244288. [PMID: 38144975 PMCID: PMC10748407 DOI: 10.3389/fpsyg.2023.1244288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 11/08/2023] [Indexed: 12/26/2023] Open
Abstract
The gist and details of an event are both important for us to establish and maintain episodic memory. On the other hand, episodic memory is influenced by both external and internal factors, such as memory cue and intrinsic motivation. To what extent these factors and their interaction modulate memory and forgetting of gist and detailed information remains unclear. In this study, 29 participants watched film clips accompanied by either gist or detailed cues and rated their interest in these clips. Their memories of gist and detailed information were tested after 10 min, 1 day, and 1 week. The results showed that memory cue modulated the forgetting of gist and detailed memories. Specifically, when gist cues were used, gist memory was forgotten more slowly than detailed memory. When detailed cues were used, detailed memory was forgotten more slowly than gist memory. Differently, the subjective interest in the clips enhanced memory accuracy irrespective of memory type but did not influence the forgetting of gist and detailed memories. Moreover, there was a significant interaction between memory cue and interest, showing that gist cues enhanced memory than detailed cues only for low-interest clips. These results suggest that external and internal factors have differential effects on memory and forgetting, and the effectiveness of external factors depends on the state of intrinsic motivation. The significant interplay of different factors in influencing the remembering or forgetting of gist and detailed memories provides potential ways to enhance memory and retention of gist and detailed information.
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Affiliation(s)
| | - Jiongjiong Yang
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
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3
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Krenz V, Alink A, Sommer T, Roozendaal B, Schwabe L. Time-dependent memory transformation in hippocampus and neocortex is semantic in nature. Nat Commun 2023; 14:6037. [PMID: 37758725 PMCID: PMC10533832 DOI: 10.1038/s41467-023-41648-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
Memories undergo a time-dependent neural reorganization, which is assumed to be accompanied by a transformation from detailed to more gist-like memory. However, the nature of this transformation and its underlying neural mechanisms are largely unknown. Here, we report that the time-dependent transformation of memory is semantic in nature, while we find no credible evidence for a perceptual transformation. Model-based MRI analyses reveal time-dependent increases in semantically transformed representations of events in prefrontal and parietal cortices, while specific pattern representations in the anterior hippocampus decline over time. Posterior hippocampal memory reinstatement, in turn, increases over time and is linked to the semantic gist of the original memory, without a statistically significant link to perceptual details. These findings indicate that qualitative changes in memory over time, associated with distinct representational changes in the neocortex and within the hippocampus, reflect a semantic transformation, which may promote the integration of memories into abstract knowledge structures.
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Affiliation(s)
- Valentina Krenz
- Department of Cognitive Psychology, Institute of Psychology, Universität Hamburg, Von-Melle-Park 5, 20146, Hamburg, Germany
| | - Arjen Alink
- Department of General Psychology, Institute of Psychology, Universität Hamburg, Von-Melle-Park 11, 20146, Hamburg, Germany
- Department of Systems Neuroscience, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Tobias Sommer
- Department of Systems Neuroscience, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Benno Roozendaal
- Department of Cognitive Neuroscience, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Kapittelweg 29, 6525 EN, Nijmegen, The Netherlands
| | - Lars Schwabe
- Department of Cognitive Psychology, Institute of Psychology, Universität Hamburg, Von-Melle-Park 5, 20146, Hamburg, Germany.
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Horwath EA, Rouhani N, DuBrow S, Murty VP. Value restructures the organization of free recall. Cognition 2023; 231:105315. [PMID: 36399901 PMCID: PMC9839530 DOI: 10.1016/j.cognition.2022.105315] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 10/12/2022] [Accepted: 10/22/2022] [Indexed: 11/17/2022]
Abstract
A large body of research illustrates the prioritization of goal-relevant information in memory; however, it is unclear how reward-related memories are organized. Using a rewarded free recall paradigm, we investigated how reward motivation structures the organization of memory around temporal and higher-order contexts. To better understand these processes, we simulated our findings using a reward-modulated variant of the Context Maintenance and Retrieval Model (CMR; Polyn et al., 2009). In the first study, we found that reward did not influence temporal clustering, but instead shifted the organization of memory based on reward category. Further, we showed that a reward-modulated learning rate and source features of CMR most accurately depict reward's enhancement on memory and clustering by value. In a second study, we showed that reward-memory effects can exist in both extended periods of sustained motivation and frequent changes in motivation, by showing equivalent reward effects using mixed- and pure-list motivation manipulations. However, we showed that a reward-modulated learning rate in isolation can support reward's enhancement of memory in pure-list contexts. Overall, we conclude that reward-related memories are adaptively organized by higher-order value information, and contextual binding to value contexts may only be necessary when rewards are intermittent versus sustained.
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Affiliation(s)
- Elizabeth A Horwath
- Department of Psychology, Temple University, Philadelphia, PA, United States of America
| | - Nina Rouhani
- Division of the Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, United States of America
| | - Sarah DuBrow
- Department of Psychology, University of Oregon, Eugene, OR, United States of America
| | - Vishnu P Murty
- Department of Psychology, Temple University, Philadelphia, PA, United States of America.
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5
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Stress disrupts insight-driven mnemonic reconfiguration in the medial temporal lobe. Neuroimage 2023; 265:119804. [PMID: 36503160 PMCID: PMC9878442 DOI: 10.1016/j.neuroimage.2022.119804] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 12/05/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
Memories are not stored in isolation. Insight into the relationship of initially unrelated events may trigger a flexible reconfiguration of the mnemonic representation of these events. Such representational changes allow the integration of events into coherent episodes and help to build up-to-date-models of the world around us. This process is, however, frequently impaired in stress-related mental disorders resulting in symptoms such as fragmented memories in PTSD. Here, we combined a real life-like narrative-insight task, in which participants learned how initially separate events are linked, with fMRI-based representational similarity analysis to test if and how acute stress interferes with the insight-driven reconfiguration of memories. Our results showed that stress reduced the activity of medial temporal and prefrontal areas when participants gained insight into the link between events. Moreover, stress abolished the insight-related increase in representational dissimilarity for linked events in the anterior part of the hippocampus as well as its association with measures of subsequent memory that we observed in non-stressed controls. However, memory performance, as assessed in a forced-choice recognition test, was even enhanced in the stress group. Our findings suggest that acute stress impedes the neural integration of events into coherent episodes but promotes long-term memory for these integrated narratives and may thus have implications for understanding memory distortions in stress-related mental disorders.
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Folvik L, Sneve MH, Ness HT, Vidal-Piñeiro D, Raud L, Geier OM, Walhovd KB, Fjell AM. Sustained upregulation of widespread hippocampal-neocortical coupling following memory encoding. Cereb Cortex 2022; 33:4844-4858. [PMID: 36190442 PMCID: PMC10110434 DOI: 10.1093/cercor/bhac384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 11/14/2022] Open
Abstract
Systems consolidation of new experiences into lasting episodic memories involves hippocampal-neocortical interactions. Evidence of this process is already observed during early post-encoding rest periods, both as increased hippocampal coupling with task-relevant perceptual regions and reactivation of stimulus-specific patterns following intensive encoding tasks. We investigate the spatial and temporal characteristics of these hippocampally anchored post-encoding neocortical modulations. Eighty-nine adults participated in an experiment consisting of interleaved memory task- and resting-state periods. We observed increased post-encoding functional connectivity between hippocampus and individually localized neocortical regions responsive to stimuli encountered during memory encoding. Post-encoding modulations were manifested as a nearly system-wide upregulation in hippocampal coupling with all major functional networks. The configuration of these extensive modulations resembled hippocampal-neocortical interaction patterns estimated from active encoding operations, suggesting hippocampal post-encoding involvement exceeds perceptual aspects. Reinstatement of encoding patterns was not observed in resting-state scans collected 12 h later, nor when using other candidate seed regions. The similarity in hippocampal functional coupling between online memory encoding and offline post-encoding rest suggests reactivation in humans involves a spectrum of cognitive processes engaged during the experience of an event. There were no age effects, suggesting that upregulation of hippocampal-neocortical connectivity represents a general phenomenon seen across the adult lifespan.
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Affiliation(s)
- Line Folvik
- Department of Psychology, Center for Lifespan Changes in Brain and Cognition, University of Oslo, Forskningsveien 3A, 0373 Oslo, Norway
| | - Markus H Sneve
- Department of Psychology, Center for Lifespan Changes in Brain and Cognition, University of Oslo, Forskningsveien 3A, 0373 Oslo, Norway
| | - Hedda T Ness
- Department of Psychology, Center for Lifespan Changes in Brain and Cognition, University of Oslo, Forskningsveien 3A, 0373 Oslo, Norway
| | - Didac Vidal-Piñeiro
- Department of Psychology, Center for Lifespan Changes in Brain and Cognition, University of Oslo, Forskningsveien 3A, 0373 Oslo, Norway
| | - Liisa Raud
- Department of Psychology, Center for Lifespan Changes in Brain and Cognition, University of Oslo, Forskningsveien 3A, 0373 Oslo, Norway
| | - Oliver M Geier
- Department of Diagnostic Physics, Oslo University Hospital, Postbox 4950 Nydalen, OUS, Rikshospitalet, 0424 Oslo, Norway
| | - Kristine B Walhovd
- Department of Psychology, Center for Lifespan Changes in Brain and Cognition, University of Oslo, Forskningsveien 3A, 0373 Oslo, Norway.,Division of Radiology and Nuclear Medicine, Oslo University Hospital, Postbox 4950 Nydalen, OUS, Rikshospitalet, 0424 Oslo, Norway
| | - Anders M Fjell
- Department of Psychology, Center for Lifespan Changes in Brain and Cognition, University of Oslo, Forskningsveien 3A, 0373 Oslo, Norway.,Division of Radiology and Nuclear Medicine, Oslo University Hospital, Postbox 4950 Nydalen, OUS, Rikshospitalet, 0424 Oslo, Norway
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Cowan ET, Liu AA, Henin S, Kothare S, Devinsky O, Davachi L. Time-dependent transformations of memory representations differ along the long axis of the hippocampus. Learn Mem 2021; 28:329-340. [PMID: 34400534 PMCID: PMC8372564 DOI: 10.1101/lm.053438.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 07/09/2021] [Indexed: 11/24/2022]
Abstract
Research has shown that sleep is beneficial for the long-term retention of memories. According to theories of memory consolidation, memories are gradually reorganized, becoming supported by widespread, distributed cortical networks, particularly during postencoding periods of sleep. However, the effects of sleep on the organization of memories in the hippocampus itself remains less clear. In a 3-d study, participants encoded separate lists of word-image pairs differing in their opportunity for sleep-dependent consolidation. Pairs were initially studied either before or after an overnight sleep period, and were then restudied in a functional magnetic resonance imaging (fMRI) scan session. We used multivariate pattern similarity analyses to examine fine-grained effects of consolidation on memory representations in the hippocampus. We provide evidence for a dissociation along the long axis of the hippocampus that emerges with consolidation, such that representational patterns for object-word memories initially formed prior to sleep become differentiated in anterior hippocampus and more similar, or overlapping, in posterior hippocampus. Differentiation in anterior hippocampal representations correlated with subsequent behavioral performance. Furthermore, representational overlap in posterior hippocampus correlated with the duration of intervening slow wave sleep. Together, these results demonstrate that sleep-dependent consolidation promotes the reorganization of memory traces along the long axis of the hippocampus.
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Affiliation(s)
- Emily T Cowan
- Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Anli A Liu
- Comprehensive Epilepsy Center, New York University, New York, New York 10016, USA
- Department of Neurology, New York University Langone Health, New York, New York 10017, USA
| | - Simon Henin
- Comprehensive Epilepsy Center, New York University, New York, New York 10016, USA
- Department of Neurology, New York University Langone Health, New York, New York 10017, USA
| | - Sanjeev Kothare
- Comprehensive Epilepsy Center, New York University, New York, New York 10016, USA
- Department of Neurology, New York University Langone Health, New York, New York 10017, USA
| | - Orrin Devinsky
- Comprehensive Epilepsy Center, New York University, New York, New York 10016, USA
- Department of Neurology, New York University Langone Health, New York, New York 10017, USA
| | - Lila Davachi
- Psychology Department, Columbia University, New York, New York 10027, USA
- Nathan Kline Institute, Orangeburg, New York 10962, USA
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