scholarly journals High feature overlap reveals the importance of anterior and medial temporal lobe structures for learning by means of fast mapping

Cortex ◽  
2021 ◽  
Author(s):  
Ann-Kathrin Zaiser ◽  
Regine Bader ◽  
Patric Meyer
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Fast Mapping ◽  
Feature Overlap

scholarly journals High feature overlap reveals the importance of anterior and medial temporal lobe structures for learning by means of fast mapping

2020 ◽  
Author(s):  
Ann-Kathrin Zaiser ◽  
Regine Bader ◽  
Patric Meyer
Keyword(s):  
Medial Temporal Lobe ◽  
Declarative Memory ◽  
Perirhinal Cortex ◽  
Semantic Integration ◽  
The Novel ◽  
Fast Mapping ◽  
Learning Procedure ◽  
Feature Overlap ◽  
High Degree ◽  
Novel Associations

AbstractContrary to traditional theories of declarative memory, it has recently been shown that novel, arbitrary associations can be rapidly and directly integrated into cortical memory networks by means of a learning procedure called fast mapping (FM), possibly bypassing time-consuming hippocampal-neocortical consolidation processes. In the typical FM paradigm, a picture of a previously unknown item is presented next to a picture of a previously known item and participants answer a question referring to an unfamiliar label. It is assumed that they thereby incidentally create associations between the unknown item and the label. However, contradictory findings have been reported and factors moderating rapid cortical integration through FM yet need to be identified. In the context of previous behavioral results showing rapid semantic integration through FM especially if the unknown and the known item shared many features, we propose that due to its computational mechanisms during the processing of complex and particularly highly similar objects, the perirhinal cortex might be especially qualified to support the rapid incorporation of these associations into cortical memory networks within the FM paradigm. We therefore expected that a high degree of feature overlap between the unknown and the known item would trigger strong engagement of the perirhinal cortex at encoding, which in turn might enhance rapid cortical integration of the novel picture-label associations. Within an fMRI experiment, we observed stronger activation for subsequent hits than misses during encoding in the perirhinal cortex and an associated anterior temporal network if the items shared many features than if they shared few features, indicating that the perirhinal cortex indeed contributes to the acquisition of novel associations by means of FM if feature overlap is high.

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.

Resolving visual and conceptual interference among object concepts requires medial temporal lobe cortex

2019 ◽  
Author(s):  
Danielle M. Douglas ◽  
Louisa Lok Yee Man ◽  
Rachel N. Newsome ◽  
Haley Park ◽  
Hira M. Aslam ◽  
...  
Keyword(s):  
Medial Temporal Lobe ◽  
Single Case ◽  
Brain Lesion ◽  
Semantic Features ◽  
Prefrontal Cortical ◽  
Visual Interference ◽  
Multiple Stimulus ◽  
Feature Overlap ◽  
Visually Based ◽  
High Degree

Semantic features, such as prototypical visual form or function, are often shared across multiple object concepts. How, then, are we able to resolve interference between object concepts that look alike but perform different functions (e.g., hairdryer and gun) or that do similar things but look rather dissimilar (e.g., hairdryer and comb)? We examined this issue in the current neuropsychological single-case study by asking whether perirhinal cortex (PRC) critically enables resolution of interference among object concepts at the level of their conceptually- and visually-based semantic features. We tested three patients with differing lesion profiles using a novel discrimination task involving stimuli for which visual and conceptual similarity were not linked across object concepts. We found that D.A., an individual with a brain lesion that includes PRC, was impaired at discriminating among object concepts when there was a high degree conceptual and visual semantic feature overlap among choices. We replicated this result in a second testing session. Conversely, patients with selective hippocampal or ventromedial prefrontal cortical lesions were unimpaired on this task. Importantly, D.A.’s performance was intact when (i) conceptual and visual interference among object concepts was minimized, and (ii) when the discriminations involved simple stimuli that did not require assessment of multiple stimulus dimensions. These results reveal a novel semantic deficit in a patient with PRC damage, suggesting that this structure represents object concepts in a manner that can be flexibly reshaped to emphasize task relevant semantic features.

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