scholarly journals Editorial: Memory Processes in Medial Temporal Lobe: Experimental, Theoretical and Computational Approaches

2017 ◽  
Vol 11 ◽  
Author(s):  
Vassilis Cutsuridis ◽  
Motoharu Yoshida
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Computational Approaches ◽  
Memory Processes

scholarly journals Spatial mnemonic encoding: Theta power decreases co-occur with medial temporal lobe BOLD increases during the usage of the Method of Loci

2016 ◽  
Author(s):  
M.-C. Fellner ◽  
G. Volberg ◽  
M. Wimber ◽  
M. Goldhacker ◽  
M. W. Greenlee ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Negative Relationship ◽  
Low Frequency ◽  
Theta Oscillations ◽  
Oscillatory Activity ◽  
Bold Signal ◽  
Memory Processes ◽  
Theta Power ◽  
Method Of Loci

AbstractThe Method of Loci is one, if not the most, efficient mnemonic encoding strategy. This strategy combines the core cognitive processes commonly linked to medial temporal lobe (MTL) activity: spatial processing and associative memory processes. During such tasks fMRI studies consistently demonstrate increases in medial temporal lobe (MTL) activity, while electrophysiological studies have emphasized the important role of theta oscillations (3-8 Hz) in the MTL. How MTL activity is linked to theta oscillatory EEG power, however, is unknown. Specifically, it is not known whether increases or decreases in MTL theta power are associated with increased BOLD signal. To investigate this question we recorded EEG and fMRI while participants used the spatial Method of Loci contrasted to the Pegword Method, a similarly associative but non spatial mnemonic. Surprisingly, the more effective spatial mnemonic induced a pronounced theta power decrease in the left MTL compared to the non-spatial associative mnemonic strategy. This effect was mirrored by BOLD signal increases in the MTL. This pattern of results suggests that theta oscillations in the MTL are negatively related to BOLD signal increases. These findings extend the well-known negative relation of alpha/beta oscillations and BOLD signals in the cortex to theta oscillations in the MTL. The results also demonstrate that decreases in theta power can index MTL involvement during encoding.Significance StatementStudies investigating the oscillatory correlates of memory encoding largely focus on activity in the theta frequency and often implicitly assume that increases in theta activity reflect similar processes as typically reported increases MTL activity changes in fMRI studies. The presented study found decreases in theta power, not increases, closely mapping to MTL BOLD signal increases during the same paradigm. This finding is in line with studies showing a negative relationship between low frequency power and BOLD changes in the cortex, but challenges the assumption that theta power increases reflect MTL activity. The reported findings importantly contribute to answer the question of how and which oscillatory activity indexes MTL memory processes.

scholarly journals Revisiting the Role of the Medial Temporal Lobe in Motor Learning

2021 ◽  
pp. 1-18
Author(s):  
Samuel D. McDougle ◽  
Sarah A. Wilterson ◽  
Nicholas B. Turk-Browne ◽  
Jordan A. Taylor
Keyword(s):  
Motor Learning ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Declarative Memory ◽  
Action Selection ◽  
Memory Systems ◽  
Memory Processes ◽  
Multiple Memory Systems ◽  
Selection Strategies ◽  
Arbitrary Action

Abstract Classic taxonomies of memory distinguish explicit and implicit memory systems, placing motor skills squarely in the latter branch. This assertion is in part a consequence of foundational discoveries showing significant motor learning in amnesics. Those findings suggest that declarative memory processes in the medial temporal lobe (MTL) do not contribute to motor learning. Here, we revisit this issue, testing an individual (L. S. J.) with severe MTL damage on four motor learning tasks and comparing her performance to age-matched controls. Consistent with previous findings in amnesics, we observed that L. S. J. could improve motor performance despite having significantly impaired declarative memory. However, she tended to perform poorly relative to age-matched controls, with deficits apparently related to flexible action selection. Further supporting an action selection deficit, L. S. J. fully failed to learn a task that required the acquisition of arbitrary action–outcome associations. We thus propose a modest revision to the classic taxonomic model: Although MTL-dependent memory processes are not necessary for some motor learning to occur, they play a significant role in the acquisition, implementation, and retrieval of action selection strategies. These findings have implications for our understanding of the neural correlates of motor learning, the psychological mechanisms of skill, and the theory of multiple memory systems.

Development of Medial Temporal Lobe Memory Processes in Nonhuman Primates

2009 ◽  
Author(s):  
Mark S. Blumberg ◽  
John H. Freeman ◽  
Scott R. Robinson ◽  
Alyson Zeamer ◽  
Maria C. Alvarado ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Nonhuman Primates ◽  
Memory Processes

scholarly journals The Contribution of the Human Medial Temporal Lobe to Perception: Bridging the Gap between Animal and Human Studies

2005 ◽  
Vol 58 (3-4b) ◽  
pp. 300-325 ◽  
Author(s):  
Andy C. H. Lee ◽  
Morgan D. Barense ◽  
Kim S. Graham
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Nonhuman Primates ◽  
Declarative Memory ◽  
Object Perception ◽  
Perirhinal Cortex ◽  
Higher Order ◽  
Human Studies ◽  
Memory Processes ◽  
Current Article

The medial temporal lobe (MTL) has been considered traditionally to subserve declarative memory processes only. Recent studies in nonhuman primates suggest, however, that the MTL may also be critical to higher order perceptual processes, with the hippocampus and perirhinal cortex being involved in scene and object perception, respectively. The current article reviews the human neuropsychological literature to determine whether there is any evidence to suggest that these same views may apply to the human MTL. Although the majority of existing studies report intact perception following MTL damage in human amnesics, there have been recent studies that suggest that when scene and object perception are assessed systematically, signifi-cant impairments in perception become apparent. These findings have important implications for current mnemonic theories of human MTL function and our understanding of human amnesia as a result of MTL lesions.

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.

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