scholarly journals Characterization of brain network supporting episodic memory in the absence of one medial temporal lobe

2019 ◽  
Vol 40 (7) ◽  
pp. 2188-2199 ◽  
Author(s):  
Woorim Jeong ◽  
Hyeongrae Lee ◽  
June Sic Kim ◽  
Chun Kee Chung
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Brain Network

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.

Modulation of medial temporal lobe activity in epilepsy patients with hippocampal sclerosis during verbal working memory

2009 ◽  
Vol 15 (4) ◽  
pp. 536-546 ◽  
Author(s):  
PABLO CAMPO ◽  
FERNANDO MAESTÚ ◽  
IRENE GARCÍA-MORALES ◽  
ANTONIO GIL-NAGEL ◽  
BRYAN STRANGE ◽  
...  
Keyword(s):  
Working Memory ◽  
Episodic Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Time Course ◽  
Hippocampal Sclerosis ◽  
Stimulus Presentation ◽  
Verbal Working Memory ◽  
Compelling Evidence ◽  
Electrophysiological Studies

AbstractIt has been traditionally assumed that medial temporal lobe (MTL) is not required for working memory (WM). However, animal lesion and electrophysiological studies and human neuropsychological and neuroimaging studies have provided increasing evidences of a critical involvement of MTL in WM. Based on previous findings, the central aim of this study was to investigate the contribution of the MTL to verbal WM encoding. Here, we used magnetoencephalography (MEG) to compare the patterns of MTL activation of 9 epilepsy patients suffering from left hippocampal sclerosis with those of 10 healthy matched controls while they performed a verbal WM task. MEG recordings allow detailed tracking of the time course of MTL activation. We observed impaired WM performance associated with changes in the dynamics of MTL activity in epilepsy patients. Specifically, whereas patients showed decreased activity in damaged MTL, activity in the contralateral MTL was enhanced, an effect that became significant in the 600- to 700-ms interval after stimulus presentation. These findings strongly support the crucial contribution of MTL to verbal WM encoding and provide compelling evidence for the proposal that MTL contributes to both episodic memory and WM. Whether this pattern is signaling reorganization or a normal use of a damaged structure is discussed. (JINS, 2009, 15, 536–546.)

scholarly journals Dynamic Theta Networks in the Human Medial Temporal Lobe Support Episodic Memory

2019 ◽  
Vol 29 (7) ◽  
pp. 1100-1111.e4 ◽  
Author(s):  
Ethan A. Solomon ◽  
Joel M. Stein ◽  
Sandhitsu Das ◽  
Richard Gorniak ◽  
Michael R. Sperling ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe

Episodic memory: It's about time (and space)

1999 ◽  
Vol 22 (3) ◽  
pp. 463-464
Author(s):  
Lynn Nadel ◽  
Lee Ryan ◽  
Katrina Keil ◽  
Karen Putnam
Keyword(s):  
Episodic Memory ◽  
Retrograde Amnesia ◽  
Temporal Lobe ◽  
Memory Consolidation ◽  
Medial Temporal Lobe ◽  
Anterograde Amnesia ◽  
Time And Space ◽  
Neuronal Ensembles ◽  
Alternative Approach

Aggleton & Brown rightly point out the shortcomings of the medial temporal lobe hypothesis as an approach to anterograde amnesia. Their broader perspective is a necessary corrective, and one hopes it will be taken very seriously. Although they correctly note the dangers of conflating recognition and recall, they themselves make a similar mistake in discussing familiarity; we suggest an alternative approach. We also discuss implications of their view for an analysis of retrograde amnesia. The notion that there are two routes by which the hippocampus can reactivate neuronal ensembles in the neocortex could help us understand some currently puzzling facts about the dynamics of memory consolidation.

scholarly journals Selectivity of pyramidal cells and interneurons in the human medial temporal lobe

2011 ◽  
Vol 106 (4) ◽  
pp. 1713-1721 ◽  
Author(s):  
Matias J. Ison ◽  
Florian Mormann ◽  
Moran Cerf ◽  
Christof Koch ◽  
Itzhak Fried ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Visual Information ◽  
Medial Temporal Lobe ◽  
Pyramidal Cells ◽  
Hierarchical Processing ◽  
Plausible Mechanism ◽  
Underlying Mechanisms ◽  
Identification And Characterization

Neurons in the medial temporal lobe (MTL) respond selectively to pictures of specific individuals, objects, and places. However, the underlying mechanisms leading to such degree of stimulus selectivity are largely unknown. A necessary step to move forward in this direction involves the identification and characterization of the different neuron types present in MTL circuitry. We show that putative principal cells recorded in vivo from the human MTL are more selective than putative interneurons. Furthermore, we report that putative hippocampal pyramidal cells exhibit the highest degree of selectivity within the MTL, reflecting the hierarchical processing of visual information. We interpret these differences in selectivity as a plausible mechanism for generating sparse responses.

scholarly journals Neural and behavioral correlates of episodic memory are associated with temporal discounting in older adults

2019 ◽  
Author(s):  
Karolina M. Lempert ◽  
Dawn J. Mechanic-Hamilton ◽  
Long Xie ◽  
Laura E.M. Wisse ◽  
Robin de Flores ◽  
...  
Keyword(s):  
Older Adults ◽  
Individual Differences ◽  
Episodic Memory ◽  
Temporal Lobe ◽  
Cortical Thickness ◽  
Medial Temporal Lobe ◽  
Structural Integrity ◽  
Temporal Discounting ◽  
Risk Tolerance ◽  
Trade Offs

AbstractWhen facing decisions involving trade-offs between smaller, sooner and larger, delayed rewards, people tend to discount the value of future rewards. There are substantial individual differences in this tendency toward temporal discounting, however. One neurocognitive system that may underlie these individual differences is episodic memory, given the overlap in the neural circuitry involved in imagining the future and remembering the past. Here we tested this hypothesis in older adults, including both those that were cognitively normal and those with amnestic mild cognitive impairment (MCI). We found that performance on neuropsychological measures of episodic memory retrieval was associated with temporal discounting, such that people with better memory discounted delayed rewards less. This relationship was specific to episodic memory and temporal discounting, since executive function (another cognitive ability) was unrelated to temporal discounting, and episodic memory was unrelated to risk tolerance (another decision-making preference). We also examined cortical thickness and volume in medial temporal lobe regions critical for episodic memory. Entorhinal cortical thickness was associated with reduced temporal discounting, with episodic memory performance partially mediating this association. The inclusion of MCI participants was critical to revealing these associations between episodic memory and entorhinal cortical thickness and temporal discounting. These effects were larger in the MCI group, reduced after controlling for MCI status, and statistically significant only when including MCI participants in analyses. Overall, these findings suggest that individual differences in temporal discounting are driven by episodic memory function, and that a decline in medial temporal lobe structural integrity may impact temporal discounting.

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