scholarly journals Overlap and separation of remembered and perceived visual information in the human medial temporal lobe

2016 ◽  
Vol 16 (12) ◽  
pp. 1429
Author(s):  
J. Benjamin Hutchinson ◽  
Yida Wang ◽  
Nicholas Turk-Browne
Keyword(s):  
Temporal Lobe ◽  
Visual Information ◽  
Medial Temporal Lobe

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.

A Double Dissociation in the Affective Modulation of Startle in Humans: Effects of Unilateral Temporal Lobectomy

2001 ◽  
Vol 13 (6) ◽  
pp. 721-729 ◽  
Author(s):  
E. Sumie Funayama ◽  
Christian Grillon ◽  
Michael Davis ◽  
Elizabeth A. Phelps
Keyword(s):  
Temporal Lobe ◽  
Visual Information ◽  
Medial Temporal Lobe ◽  
Emotional Processing ◽  
Right Hemisphere ◽  
Temporal Lobectomy ◽  
Opposite Pattern ◽  
Double Dissociation ◽  
Control Subjects ◽  
The Right

In the present study we report a double dissociation between right and left medial temporal lobe damage in the modulation of fear responses to different types of stimuli. We found that right unilateral temporal lobectomy (RTL) patients, in contrast to control subjects and left temporal lobectomy (LTL) patients, failed to show potentiated startle while viewing negative pictures. However, the opposite pattern of impairment was observed during a stimulus that patients had been told signaled the possibility of shock. Control subjects and RTL patients showed potentiated startle while LTL patients failed to show potentiated startle. We hypothesize that the right medial temporal lobe modulates fear responses while viewing emotional pictures, which involves exposure to (emotional) visual information and is consistent with the emotional processing traditionally ascribed to the right hemisphere. In contrast, the left medial temporal lobe modulates fear responses when those responses are the result of a linguistic/cognitive representation acquired through language, which, like other verbally mediated material, generally involves the left hemisphere. Additional evidence from case studies suggests that, within the medial temporal lobe, the amygdala is responsible for this modulation.

scholarly journals Neuronal firing in the medial temporal lobe reflects human working memory workload, performance and capacity

2020 ◽  
Author(s):  
Ece Boran ◽  
Peter Hilfiker ◽  
Lennart Stieglitz ◽  
Thomas Grunwald ◽  
Johannes Sarnthein ◽  
...  
Keyword(s):  
Working Memory ◽  
Temporal Lobe ◽  
Visual Information ◽  
Medial Temporal Lobe ◽  
Memory Task ◽  
Individual Performance ◽  
Neuronal Firing ◽  
Maintenance Period ◽  
Multiple Objects ◽  
Short Period

2AbstractThe involvement of the medial temporal lobe (MTL) in working memory is controversially discussed. Critically, it is unclear whether and how the MTL supports performance of working memory. We recorded single neuron firing in 13 epilepsy patients while they performed a visual working memory task. The number of colored squares in the stimulus set determined the workload of the trial. We used the subjects’ memory capacity (Cowan’s K) to split them into a low and high capacity group. We found MTL neurons that showed persistent firing during the maintenance period. Firing was higher in the hippocampus for trials with correct compared to incorrect performance. Population firing predicted workload particularly during the maintenance period. Prediction accuracy of single trial activity was strongest for neurons in the entorhinal cortex of low capacity subjects. We provide evidence that low capacity subjects recruit their MTL to cope with an overload of working memory task demands.1SignificanceHumans are highly limited in processing multiple objects over a short period of time. The capacity to retain multiple objects in working memory is typically associated with frontal and parietal lobe functioning, even though medial temporal lobe (MTL) neural architecture seems capable to process such information. However, there are conflicting findings from patient, electrophysiological and neuroimaging studies. Here we show for the first time that correct performance, workload and individual performance differences are reflected in separate mechanisms of neural activity within the MTL during maintenance of visual information in working memory. The data suggest that low capacity subjects use the MTL to process the overload of information.

scholarly journals Feature-based encoding of face identity by single neurons in the human medial temporal lobe

2020 ◽  
Author(s):  
Runnan Cao ◽  
Jinge Wang ◽  
Chujun Lin ◽  
Ueli Rutishauser ◽  
Alexander Todorov ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Temporal Lobe ◽  
Visual Information ◽  
Medial Temporal Lobe ◽  
Declarative Memory ◽  
Semantic Representation ◽  
Feature Space ◽  
Face Identity ◽  
Feature Based ◽  
Face Stimuli

AbstractNeurons in the human medial temporal lobe (MTL) that are selective for the identity of specific people are classically thought to encode identity invariant to visual features. However, it remains largely unknown how visual information from higher visual cortex is translated into a semantic representation of an individual person. Here, we show that some MTL neurons are selective to multiple different face identities on the basis of shared features that form clusters in the representation of a deep neural network trained to recognize faces. Contrary to prevailing views, we find that these neurons represent an individual’s face with feature-based encoding, rather than through association with concepts. The response of feature neurons did not depend on face identity nor face familiarity, and the region of feature space to which they are tuned predicted their response to new face stimuli. Our results provide critical evidence bridging the perception-driven representation of facial features in the higher visual cortex and the memory-driven representation of semantics in the MTL, which may form the basis for declarative memory.

scholarly journals Saccades phase-locked to alpha oscillations in the occipital and medial temporal lobe enhance memory encoding

2017 ◽  
Author(s):  
Tobias Staudigl ◽  
Elisabeth Hartl ◽  
Soheyl Noachtar ◽  
Christian F. Doeller ◽  
Ole Jensen
Keyword(s):  
Eye Movements ◽  
Temporal Lobe ◽  
Visual Information ◽  
Medial Temporal Lobe ◽  
Retrosplenial Cortex ◽  
Neural Oscillations ◽  
Memory Encoding ◽  
Alpha Oscillations ◽  
Memory Mapping ◽  
Efficient Sampling

AbstractEfficient sampling of visual information requires a coordination of eye movements and ongoing brain oscillations. Using intracranial and MEG recordings, we show that saccades are locked to the phase of visual alpha oscillations, and that this coordination supports mnemonic encoding of visual scenes. Furthermore, parahippocampal and retrosplenial cortex involvement in this coordination reflects effective vision-to-memory mapping, highlighting the importance of neural oscillations for the interaction between visual and memory domains.

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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