scholarly journals CA1 and CA3 differentially support spontaneous retrieval of episodic contexts within human hippocampal subfields

2017 ◽  
Author(s):  
Halle R. Dimsdale-Zucker ◽  
Maureen Ritchey ◽  
Arne D. Ekstrom ◽  
Andrew P. Yonelinas ◽  
Charan Ranganath
Keyword(s):  
Episodic Memory ◽  
Multivariate Analyses ◽  
Contextual Information ◽  
Critical Role ◽  
Mechanistic Models ◽  
Opposite Pattern ◽  
Hippocampal Subfields ◽  
Neural Representations ◽  
Pattern Similarity ◽  
Spontaneous Retrieval

AbstractThe hippocampus plays a critical role in spatial and episodic memory. Mechanistic models predict that hippocampal subfields have computational specializations that differentially support memory. However, there is little empirical evidence suggesting differences between the subfields, particularly in humans. To clarify how hippocampal subfields support human spatial and episodic memory, we developed a virtual reality paradigm where participants passively navigated through houses (spatial contexts) across a series of videos (episodic contexts). We then used multivariate analyses of high-resolution fMRI data to identify neural representations of contextual information during recollection. Multi-voxel pattern similarity analyses revealed that CA1 represented objects that shared an episodic context as more similar than those from different episodic contexts. CA23DG showed the opposite pattern, differentiating between objects encountered in the same episodic context. The complementary characteristics of these subfields explain how we can parse our experiences into cohesive episodes while retaining the specific details that support vivid recollection.

Hippocampal subfields integrate information about past temporal and cognitive contexts

2019 ◽  
Author(s):  
Halle R. Dimsdale-Zucker ◽  
Maria E. Montchal ◽  
Zachariah M. Reagh ◽  
Shao-Fang Wang ◽  
Laura A. Libby ◽  
...  
Keyword(s):  
High Resolution ◽  
Episodic Memory ◽  
Activity Patterns ◽  
Critical Role ◽  
Coarse Grained ◽  
Temporal Context ◽  
Hippocampal Subfields ◽  
Cognitive States ◽  
Pattern Similarity ◽  
Temporal Intervals

AbstractThe hippocampus plays a critical role in supporting episodic memory. Although we know that temporal context is a defining feature of episodic memory, we understand relatively little about how this information may be represented by the hippocampus. Research in rodents has suggested that the hippocampus represents temporal information on an absolute scale or in terms of relative temporal intervals, but cognitive models of memory have argued that temporal context in episodic memory is a consequence of changes in cognitive states and experiences. Here, we combined high-resolution fMRI imaging with voxel pattern similarity analyses to answer the question of how human hippocampal subfields represent retrieved information about cognitive states and the time at which a past event took place. As participants recollected previously presented items, activity patterns in the CA23DG subregion carried information about prior cognitive states, along with coarse-grained information about when the item was previously encountered. These findings are consistent with the idea that CA23DG supports temporal context in episodic memory by encoding an integrated representation of discrete and gradually-changing cognitive states.

scholarly journals Representations of local spatial information in the human medial temporal lobe during memory-guided navigation

2020 ◽  
Author(s):  
Shao-Fang Wang ◽  
Valerie A. Carr ◽  
Serra E. Favila ◽  
Jeremy N. Bailenson ◽  
Thackery I. Brown ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Spatial Information ◽  
Activity Patterns ◽  
Critical Role ◽  
Neural Representations ◽  
Parahippocampal Cortex ◽  
Pattern Similarity ◽  
Cortical Regions ◽  
Goal Directed Behavior

AbstractThe hippocampus (HC) and surrounding medial temporal lobe (MTL) cortical regions play a critical role in spatial navigation and episodic memory. However, it remains unclear how the interaction between the HC’s conjunctive coding and mnemonic differentiation contributes to neural representations of spatial environments. Multivariate functional magnetic resonance imaging (fMRI) analyses enable examination of how human HC and MTL cortical regions encode multidimensional spatial information to support memory-guided navigation. We combined high-resolution fMRI with a virtual navigation paradigm in which participants relied on memory of the environment to navigate to goal locations in two different virtual rooms. Within each room, participants were cued to navigate to four learned locations, each associated with one of two reward values. Pattern similarity analysis revealed that when participants successfully arrived at goal locations, activity patterns in HC and parahippocampal cortex (PHC) represented room-goal location conjunctions and activity patterns in HC subfields represented room-reward-location conjunctions. These results add to an emerging literature revealing hippocampal conjunctive representations during goal-directed behavior.

scholarly journals Delay-dependent contributions of medial temporal lobe regions to episodic memory retrieval

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Maureen Ritchey ◽  
Maria E Montchal ◽  
Andrew P Yonelinas ◽  
Charan Ranganath
Keyword(s):  
Episodic Memory ◽  
Medial Temporal Lobe ◽  
Functional Neuroimaging ◽  
Contextual Information ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Pattern Similarity ◽  
Delayed Recognition ◽  
Delay Dependent ◽  
Over Time

The medial temporal lobes play an important role in episodic memory, but over time, hippocampal contributions to retrieval may be diminished. However, it is unclear whether such changes are related to the ability to retrieve contextual information, and whether they are common across all medial temporal regions. Here, we used functional neuroimaging to compare neural responses during immediate and delayed recognition. Results showed that recollection-related activity in the posterior hippocampus declined after a 1-day delay. In contrast, activity was relatively stable in the anterior hippocampus and in neocortical areas. Multi-voxel pattern similarity analyses also revealed that anterior hippocampal patterns contained information about context during item recognition, and after a delay, context coding in this region was related to successful retention of context information. Together, these findings suggest that the anterior and posterior hippocampus have different contributions to memory over time and that neurobiological models of memory must account for these differences.

Contributions of representational distinctiveness and stability to memory performance and age differences

2021 ◽  
Author(s):  
Verena R. Sommer ◽  
Myriam C. Sander
Keyword(s):  
Episodic Memory ◽  
Age Differences ◽  
Cognitive Aging ◽  
Memory Performance ◽  
Activity Patterns ◽  
Stimulus Category ◽  
Neural Representations ◽  
Age Related ◽  
Pattern Similarity ◽  
Versatile Tool

Long-standing theories of cognitive aging suggest that memory decline is associated with age-related differences in the way information is represented in the brain. In the last years, these hypotheses have been substantiated by novel neuroscientific evidence that was derived from multivariate pattern similarity analyses. This approach enabled researchers to take a representational perspective on brain and cognition, and allowed them to study the properties of neural representations that support successful episodic memory. In young adults, two prominent representational properties have been identified as crucial for memory performance, namely the distinctiveness and the stability of neural representations. Distinctiveness describes the relation of neural representations to each other, i.e., how similar or dissimilar they are, while stability characterizes how much or how little representations change over time. However, researchers have only recently started to explore age differences in these representational properties and how they interact to support episodic memory in old age. Here, we review studies that used multivariate analysis tools for different neuroimaging techniques to clarify how representational distinctiveness, stability, and their interactions relate to memory performance across adulthood, and specifically during aging. While most evidence on age differences in neural representations involved how stimulus category information is represented, recent studies demonstrated that particularly item-level stability and specificity of activity patterns are positively linked to memory success and decline during aging. Overall, multivariate methods offer a promising and versatile tool for our understanding of age differences in the neural representations underlying episodic memory.

scholarly journals The Hippocampus Generalizes across Memories that Share Item and Context Information

2019 ◽  
Vol 31 (1) ◽  
pp. 24-35 ◽  
Author(s):  
Laura A. Libby ◽  
Zachariah M. Reagh ◽  
Nichole R. Bouffard ◽  
J. Daniel Ragland ◽  
Charan Ranganath
Keyword(s):  
Episodic Memory ◽  
Multivariate Analyses ◽  
Contextual Information ◽  
Activity Patterns ◽  
Context Information ◽  
Major Area ◽  
Hippocampal Activity ◽  
Similar Item ◽  
Single Attribute ◽  
The Way

Episodic memory is known to rely on the hippocampus, but how the hippocampus organizes different episodes to permit their subsequent retrieval remains controversial. One major area of debate hinges on a discrepancy between two hypothesized roles of the hippocampus: differentiating between similar events to reduce interference and assigning similar representations to events that share overlapping items and contextual information. Here, we used multivariate analyses of activity patterns measured with fMRI to characterize how the hippocampus distinguishes between memories based on similarity at the level of items and/or context. Hippocampal activity patterns discriminated between events that shared either item or context information but generalized across events that shared similar item–context associations. The current findings provide evidence that, whereas the hippocampus can reduce mnemonic interference by separating events that generalize along a single attribute dimension, overlapping hippocampal codes may support memory for events with overlapping item–context relations. This lends new insights into the way the hippocampus may balance multiple mnemonic operations in adaptively guiding behavior.

Children show adult-like hippocampal pattern separation for familiar but not novel events

2020 ◽  
Author(s):  
Susan L. Benear ◽  
Elizabeth A. Horwath ◽  
Emily Cowan ◽  
M. Catalina Camacho ◽  
Chi Ngo ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Developmental Change ◽  
Pattern Separation ◽  
Developmental Changes ◽  
Similarity Analysis ◽  
Separation Processes ◽  
Parahippocampal Cortex ◽  
Pattern Similarity

The medial temporal lobe (MTL) undergoes critical developmental change throughout childhood, which aligns with developmental changes in episodic memory. We used representational similarity analysis to compare neural pattern similarity for children and adults in hippocampus and parahippocampal cortex during naturalistic viewing of clips from the same movie or different movies. Some movies were more familiar to participants than others. Neural pattern similarity was generally lower for clips from the same movie, indicating that related content taxes pattern separation-like processes. However, children showed this effect only for movies with which they were familiar, whereas adults showed the effect consistently. These data suggest that children need more exposures to stimuli in order to show mature pattern separation processes.

The Role of the Medial Prefrontal Cortex in Moderating Neural Representations of Self and Other in Primates

2021 ◽  
Vol 44 (1) ◽  
Author(s):  
Masaki Isoda
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Critical Role ◽  
Autism Spectrum ◽  
Annual Review ◽  
Publication Date ◽  
Self And Other ◽  
Neural Representations ◽  
The Social

As a frontal node in the primate social brain, the medial prefrontal cortex (MPFC) plays a critical role in coordinating one's own behavior with respect to that of others. Current literature demonstrates that single neurons in the MPFC encode behavior-related variables such as intentions, actions, and rewards, specifically for self and other, and that the MPFC comes into play when reflecting upon oneself and others. The social moderator account of MPFC function can explain maladaptive social cognition in people with autism spectrum disorder, which tips the balance in favor of self-centered perspectives rather than taking into consideration the perspective of others. Several strands of evidence suggest a hypothesis that the MPFC represents different other mental models, depending on the context at hand, to better predict others’ emotions and behaviors. This hypothesis also accounts for aberrant MPFC activity in autistic individuals while they are mentalizing others. Expected final online publication date for the Annual Review of Neuroscience, Volume 44 is July 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Proactive coping mediates the relationship between the narcissism phenotypes and psychological health

2021 ◽  
Vol 49 (7) ◽  
pp. 1-15
Author(s):  
Seungju Hyun ◽  
Xyle Ku
Keyword(s):  
Psychological Health ◽  
Critical Role ◽  
Proactive Coping ◽  
Multiple Mediation ◽  
Opposite Pattern ◽  
Vulnerable Narcissism ◽  
Mediating Role ◽  
And Gender ◽  
The Relationship

Although the relationship between grandiose and vulnerable narcissism and psychological health is widely accepted, little is known about whether and how coping strategies explain this relationship. We examined the mediating role of proactive coping in this relationship, with a sample of 280 participants from five colleges in Korea. We used four parallel multiple mediation models, and controlled for the indirect effects of coping flexibility, self-esteem, and covariates (age and gender). Results show that grandiose narcissism predicted higher life satisfaction and lower perceived stress, whereas vulnerable narcissism exhibited the opposite pattern, and all of these relationships were mediated by proactive coping. Overall, our results highlight the critical role of proactive coping in the prediction of psychological health among narcissists.

scholarly journals Neural representations of honesty predict future trust behavior

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Gabriele Bellucci ◽  
Felix Molter ◽  
Soyoung Q. Park
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Multivariate Analyses ◽  
Posterior Cingulate Cortex ◽  
Ventromedial Prefrontal Cortex ◽  
Intraparietal Sulcus ◽  
Temporoparietal Junction ◽  
Neural Representations ◽  
Brain Signals ◽  
Dorsolateral Prefrontal

AbstractTheoretical accounts propose honesty as a central determinant of trustworthiness impressions and trusting behavior. However, behavioral and neural evidence on the relationships between honesty and trust is missing. Here, combining a novel paradigm that successfully induces trustworthiness impressions with functional MRI and multivariate analyses, we demonstrate that honesty-based trustworthiness is represented in the posterior cingulate cortex, dorsolateral prefrontal cortex and intraparietal sulcus. Crucially, brain signals in these regions predict individual trust in a subsequent social interaction with the same partner. Honesty recruited the ventromedial prefrontal cortex (VMPFC), and stronger functional connectivity between the VMPFC and temporoparietal junction during honesty encoding was associated with higher trust in the subsequent interaction. These results suggest that honesty signals in the VMPFC are integrated into trustworthiness beliefs to inform present and future social behaviors. These findings improve our understanding of the neural representations of an individual’s social character that guide behaviors during interpersonal interactions.

scholarly journals Context-Aware Self-Attention Networks

2019 ◽  
Vol 33 ◽  
pp. 387-394 ◽  
Author(s):  
Baosong Yang ◽  
Jian Li ◽  
Derek F. Wong ◽  
Lidia S. Chao ◽  
Xing Wang ◽  
...  
Keyword(s):  
English Translation ◽  
Contextual Information ◽  
The Self ◽  
Context Aware ◽  
Short Term ◽  
Internal Representations ◽  
Attention Networks ◽  
External Resources ◽  
Attention Model ◽  
Neural Representations

Self-attention model has shown its flexibility in parallel computation and the effectiveness on modeling both long- and short-term dependencies. However, it calculates the dependencies between representations without considering the contextual information, which has proven useful for modeling dependencies among neural representations in various natural language tasks. In this work, we focus on improving self-attention networks through capturing the richness of context. To maintain the simplicity and flexibility of the self-attention networks, we propose to contextualize the transformations of the query and key layers, which are used to calculate the relevance between elements. Specifically, we leverage the internal representations that embed both global and deep contexts, thus avoid relying on external resources. Experimental results on WMT14 English⇒German and WMT17 Chinese⇒English translation tasks demonstrate the effectiveness and universality of the proposed methods. Furthermore, we conducted extensive analyses to quantify how the context vectors participate in the self-attention model.

Sign in / Sign up

Export Citation Format

Share Document