scholarly journals Semantics of the Visual Environment Encoded in Parahippocampal Cortex

2016 ◽  
Vol 28 (3) ◽  
pp. 361-378 ◽  
Author(s):  
Michael F. Bonner ◽  
Amy Rose Price ◽  
Jonathan E. Peelle ◽  
Murray Grossman
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Critical Role ◽  
Primary Progressive Aphasia ◽  
Semantic Knowledge ◽  
Individual Variability ◽  
Visual Environment ◽  
Parahippocampal Cortex ◽  
Visual Concepts ◽  
High Level

Semantic representations capture the statistics of experience and store this information in memory. A fundamental component of this memory system is knowledge of the visual environment, including knowledge of objects and their associations. Visual semantic information underlies a range of behaviors, from perceptual categorization to cognitive processes such as language and reasoning. Here we examine the neuroanatomic system that encodes visual semantics. Across three experiments, we found converging evidence indicating that knowledge of verbally mediated visual concepts relies on information encoded in a region of the ventral-medial temporal lobe centered on parahippocampal cortex. In an fMRI study, this region was strongly engaged by the processing of concepts relying on visual knowledge but not by concepts relying on other sensory modalities. In a study of patients with the semantic variant of primary progressive aphasia (semantic dementia), atrophy that encompassed this region was associated with a specific impairment in verbally mediated visual semantic knowledge. Finally, in a structural study of healthy adults from the fMRI experiment, gray matter density in this region related to individual variability in the processing of visual concepts. The anatomic location of these findings aligns with recent work linking the ventral-medial temporal lobe with high-level visual representation, contextual associations, and reasoning through imagination. Together, this work suggests a critical role for parahippocampal cortex in linking the visual environment with knowledge systems in the human brain.

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 Investigating the Interaction between Spatial Perception and Working Memory in the Human Medial Temporal Lobe

2010 ◽  
Vol 22 (12) ◽  
pp. 2823-2835 ◽  
Author(s):  
Andy C. H. Lee ◽  
Sarah R. Rudebeck
Keyword(s):  
Working Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Scene Perception ◽  
Critical Role ◽  
Memory Task ◽  
Spatial Processing ◽  
Processing Conditions ◽  
Parahippocampal Cortex

There has been considerable debate surrounding the functions of the medial temporal lobe (MTL). Although this region has been traditionally thought to subserve long-term declarative memory only, recent evidence suggests a role in short-term working memory and even higher order perception. To investigate this issue, functional neuroimaging was used to investigate the involvement of the MTL in spatial scene perception and working memory. Healthy participants were scanned during a working memory task incorporating two factors of working memory (high vs. low demand) and spatial processing (complex vs. simple). It was found that an increase in spatial processing demand produced significantly greater activity in the posterior hippocampus and parahippocampal cortex irrespective of whether working memory demand was high or low. In contrast, there was no region within the MTL that increased significantly in activity during both the complex and the simple spatial processing conditions when working memory demand was increased. There was, however, a significant interaction effect between spatial processing and working memory in the right posterior hippocampus and parahippocampal cortex bilaterally: An increase in working memory demand produced a significant increase in activity in these areas during the complex, but not simple, spatial processing conditions. These findings suggest that although there may be a role for the MTL in both stimulus processing and working memory, increasing the latter does not necessarily increase posterior MTL involvement. We suggest that these structures may play a critical role in processing complex spatial representations, which, in turn, may form the basis of short- and long-term mnemonic processes.

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.

scholarly journals Thalamic-Medial Temporal Lobe Connectivity Underpins Familiarity Memory

2020 ◽  
Vol 30 (6) ◽  
pp. 3827-3837 ◽  
Author(s):  
Alex Kafkas ◽  
Andrew R Mayes ◽  
Daniela Montaldi
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Critical Role ◽  
Dynamic Interaction ◽  
Thalamic Nuclei ◽  
Neural Basis ◽  
General Role ◽  
Anterior Thalamus ◽  
Ventrolateral Thalamus ◽  
Familiarity And Recollection

Abstract The neural basis of memory is highly distributed, but the thalamus is known to play a particularly critical role. However, exactly how the different thalamic nuclei contribute to different kinds of memory is unclear. Moreover, whether thalamic connectivity with the medial temporal lobe (MTL), arguably the most fundamental memory structure, is critical for memory remains unknown. We explore these questions using an fMRI recognition memory paradigm that taps familiarity and recollection (i.e., the two types of memory that support recognition) for objects, faces, and scenes. We show that the mediodorsal thalamus (MDt) plays a material-general role in familiarity, while the anterior thalamus plays a material-general role in recollection. Material-specific regions were found for scene familiarity (ventral posteromedial and pulvinar thalamic nuclei) and face familiarity (left ventrolateral thalamus). Critically, increased functional connectivity between the MDt and the parahippocampal (PHC) and perirhinal cortices (PRC) of the MTL underpinned increases in reported familiarity confidence. These findings suggest that familiarity signals are generated through the dynamic interaction of functionally connected MTL-thalamic structures.

scholarly journals The Medial Temporal Lobe Is Critical for Spatial Relational Perception

2020 ◽  
Vol 32 (9) ◽  
pp. 1780-1795 ◽  
Author(s):  
Nicholas A. Ruiz ◽  
Michael R. Meager ◽  
Sachin Agarwal ◽  
Mariam Aly
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Critical Role ◽  
Long Term Memory ◽  
Term Memory ◽  
Cognitive Domains ◽  
Attention Tasks ◽  
Human Participants ◽  
Attention And Perception

The medial temporal lobe (MTL) is traditionally considered to be a system that is specialized for long-term memory. Recent work has challenged this notion by demonstrating that this region can contribute to many domains of cognition beyond long-term memory, including perception and attention. One potential reason why the MTL (and hippocampus specifically) contributes broadly to cognition is that it contains relational representations—representations of multidimensional features of experience and their unique relationship to one another—that are useful in many different cognitive domains. Here, we explore the hypothesis that the hippocampus/MTL plays a critical role in attention and perception via relational representations. We compared human participants with MTL damage to healthy age- and education-matched individuals on attention tasks that varied in relational processing demands. On each trial, participants viewed two images (rooms with paintings). On “similar room” trials, they judged whether the rooms had the same spatial layout from a different perspective. On “similar art” trials, they judged whether the paintings could have been painted by the same artist. On “identical” trials, participants simply had to detect identical paintings or rooms. MTL lesion patients were significantly and selectively impaired on the similar room task. This work provides further evidence that the hippocampus/MTL plays a ubiquitous role in cognition by virtue of its relational and spatial representations and highlights its important contributions to rapid perceptual processes that benefit from attention.

Forward Processing of Object–Location Association from the Ventral Stream to Medial Temporal Lobe in Nonhuman Primates

2019 ◽  
Vol 30 (3) ◽  
pp. 1260-1271 ◽  
Author(s):  
He Chen ◽  
Yuji Naya
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Spatial Information ◽  
Object Location ◽  
Object Identity ◽  
Downstream Target ◽  
Parahippocampal Cortex ◽  
Ventral Pathway ◽  
Additive Form ◽  
Location Association

Abstract While the hippocampus (HPC) is a prime candidate combining object identity and location due to its strong connections to the ventral and dorsal pathways via surrounding medial temporal lobe (MTL) areas, recent physiological studies have reported spatial information in the ventral pathway and its downstream target in MTL. However, it remains unknown whether the object–location association proceeds along the ventral MTL pathway before HPC. To address this question, we recorded neuronal activity from MTL and area anterior inferotemporal cortex (TE) of two macaques gazing at an object to retain its identity and location in each trial. The results showed significant effects of object–location association at a single-unit level in TE, perirhinal cortex (PRC), and HPC, but not in the parahippocampal cortex. Notably, a clear area difference emerged in the association form: 1) representations of object identity were added to those of subjects’ viewing location in TE; 2) PRC signaled both the additive form and the conjunction of the two inputs; and 3) HPC signaled only the conjunction signal. These results suggest that the object and location signals are combined stepwise at TE and PRC each time primates view an object, and PRC may provide HPC with the conjunctional signal, which might be used for encoding episodic memory.

P4-298: MEDIAL TEMPORAL LOBE SUBREGIONAL ATROPHY PATTERN IN SEMANTIC VARIANT PRIMARY PROGRESSIVE APHASIA AND ASSOCIATIONS WITH COGNITIVE IMPAIRMENTS

2006 ◽  
Vol 14 (7S_Part_30) ◽  
pp. P1565-P1565 ◽  
Author(s):  
Laura Wisse ◽  
Molly Ungrady ◽  
David A. Wolk ◽  
David J. Irwin ◽  
Corey T. McMillan ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Cognitive Impairments ◽  
Primary Progressive Aphasia ◽  
Progressive Aphasia ◽  
Primary Progressive ◽  
Semantic Variant

Episodic Inputs to Moral Cognition: The Role of Memory and Imagination in Shaping the Moral Mind

2020 ◽  
Author(s):  
Brendan Gaesser ◽  
Zoe Fowler
Keyword(s):  
Decision Making ◽  
Moral Judgment ◽  
Medial Temporal Lobe ◽  
Critical Role ◽  
Empirical Work ◽  
Semantic Knowledge ◽  
Judgment And Decision Making ◽  
Human Cognition ◽  
Moral Cognition ◽  
Affective Processes

Research in psychology, neuroscience, and philosophy has proposed a multifaceted view of human cognition and morality, establishing that inputs from multiple cognitive and affective processes such as theory of mind, semantic knowledge, and language guide moral judgment and decision-making. However, the extant perspective of moral cognition has largely overlooked a critical role for episodic representation. The ability to remember or imagine a specific moment in the past or future, supported by the medial temporal lobe subsystem, plays a broadly influential role in how people think, feel, and behave. Yet existing research has only just begun to explore the influence of episodic representation on moral judgment and decision-making. Here, we evaluate the theoretical connections between episodic representation and moral judgment, review emerging empirical work revealing how episodic representation affects moral judgment and decision-making, and conclude by highlighting gaps in the literature and future directions to explore. We argue that a comprehensive model of moral cognition will require including contributions of the episodic memory system, further delineating its direct influence on morality as well as better understanding how this system engages and interacts with other mental processes to fundamentally shape human morality.

scholarly journals High-resolution fMRI Reveals Match Enhancement and Attentional Modulation in the Human Medial Temporal Lobe

2011 ◽  
Vol 23 (3) ◽  
pp. 670-682 ◽  
Author(s):  
Nicole M. Dudukovic ◽  
Alison R. Preston ◽  
Jermaine J. Archie ◽  
Gary H. Glover ◽  
Anthony D. Wagner
Keyword(s):  
High Resolution ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Relational Memory ◽  
Relevant Stimulus ◽  
Match To Sample ◽  
The Past ◽  
Human Hippocampus ◽  
Parahippocampal Cortex ◽  
Familiar Stimuli

A primary function of the medial temporal lobe (MTL) is to signal prior encounter with behaviorally relevant stimuli. MTL match enhancement—increased activation when viewing previously encountered stimuli—has been observed for goal-relevant stimuli in nonhuman primates during delayed-match-to-sample tasks and in humans during more complex relational memory tasks. Match enhancement may alternatively reflect (a) an attentional response to familiar relative to novel stimuli or (b) the retrieval of contextual details surrounding the past encounter with familiar stimuli. To gain leverage on the functional significance of match enhancement in the hippocampus, high-resolution fMRI of human MTL was conducted while participants attended, ignored, or passively viewed face and scene stimuli in the context of a modified delayed-match-to-sample task. On each “attended” trial, two goal-relevant stimuli were encountered before a probe that either matched or mismatched one of the attended stimuli, enabling examination of the consequences of encountering one of the goal-relevant stimuli as a match probe on later memory for the other (nonprobed) goal-relevant stimulus. fMRI revealed that the hippocampus was insensitive to the attentional manipulation, whereas parahippocampal cortex was modulated by scene-directed attention, and perirhinal cortex showed more subtle and general effects of attention. By contrast, all hippocampal subfields demonstrated match enhancement to the probe, and a postscan test revealed more accurate recognition memory for the nonprobed goal-relevant stimulus on match relative to mismatch trials. These data suggest that match enhancement in human hippocampus reflects retrieval of other goal-relevant contextual details surrounding a stimulus's prior encounter.

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