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Signal strength determines the nature of the relationship between perception and working memory

Sheth, Bhavin R. and Shimojo, Shinsuke (2003) Signal strength determines the nature of the relationship between perception and working memory. Journal of Cognitive Neuroscience, 15 (2). pp. 173-184. ISSN 0898-929X. http://resolver.caltech.edu/CaltechAUTHORS:SHEjcn03

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Abstract

Neurophysiological and behavioral studies have shown that perception and memory share neural substrates and functional properties. But are perception and the active working memory of a stimulus one and the same? To address this question in the spatial domain, we compared the percept and the working memory of the position of a target stimulus embedded within a surround of moving dots. Motion in a particular direction after the target's offset biased the memory of target location in the same direction. However, motion simultaneous with a high-contrast, perceptually strong target biased the percept of target location in the opposite direction. Thus, perception and working memory can be modified by motion in qualitatively different ways. Manipulations to strengthen the memory trace had no effect on the direction of the memory bias, indicating that memory signal strength can never equal that of the percept of a strong stimulus. However, the percept of a weak stimulus was biased in the direction of motion. Thus, although perception and working memory are not inherently different, they can differ behaviorally depending on the strength of the perceptual signal. Understanding how a changing surround biases neural representations in general, and postsensory processes in particular, can help one understand past reports of spatial mislocalization.


Item Type:Article
Additional Information:© 2003 The MIT Press. We thank Beena Khurana, Johanna Weber, and Patrick Cavanagh for reviewing several earlier versions of the manuscript. Thanks are also due Marvin Chun for critical reading of a later draft. Finally, a special thanks to Daw-An Wu for proofreading the final draft, and for all kinds of help too numerous to mention.
Subject Keywords:PERCEIVED POSITION; PSYCHOMETRIC FUNCTIONS; VISUAL-IMAGERY; MOTION; SPACE; AREA; DISSOCIATION; PSYCHOPHYSICS; CORTEX; PET
Record Number:CaltechAUTHORS:SHEjcn03
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:SHEjcn03
Alternative URL:http://jocn.mitpress.org/cgi/content/abstract/15/2/173
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4734
Collection:CaltechAUTHORS
Deposited By: Lindsay Cleary
Deposited On:05 Sep 2006
Last Modified:26 Dec 2012 09:01

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