Spontaneously reactivated patterns in frontal and temporal lobe predict semantic clustering during memory search.

Publication/Presentation Date

6-27-2012

Abstract

Although it is well established that remembering an item will bring to mind memories of other semantically related items (Bousfield, 1953), the neural basis of this phenomenon is poorly understood. We studied how the similarity relations among items influence their retrieval by analyzing electrocorticographic recordings taken as 46 human neurosurgical patients studied and freely recalled lists of words. We first identified semantic components of neural activity that varied systematically with the meanings of each studied word, as defined by latent semantic analysis (Landauer and Dumais, 1997). We then examined the dynamics of these semantic components as participants attempted to recall the previously studied words. Our analyses revealed that the semantic components of neural activity were spontaneously reactivated during memory search, just before recall of the studied words. Further, the degree to which neural activity correlated with semantic similarity during recall predicted participants' tendencies to organize the sequences of their responses on the basis of semantic similarity. Thus, our work shows that differences in the neural correlates of semantic information, and how they are reactivated before recall, reveal how individuals organize and retrieve memories of words.

Volume

32

Issue

26

First Page

8871

Last Page

8878

ISSN

1529-2401

Disciplines

Medicine and Health Sciences

PubMedID

22745488

Department(s)

Department of Medicine

Document Type

Article

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