Neural correlates of maintaining generated images in visual working memory

Ewerdwalbesloh, J. A., Palva, S. , Rösler, F. and Khader, P. H. (2016) Neural correlates of maintaining generated images in visual working memory. Human Brain Mapping, 37(12), pp. 4349-4362. (doi: 10.1002/hbm.23313) (PMID:27411499)

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Abstract

How are images that have been assembled from their constituting elements maintained as a coherent representation in visual working memory (vWM)? Here, we compared two conditions of vWM maintenance that only differed in how vWM contents had been created. Participants maintained images that they either had to assemble from single features or that they had perceived as complete objects. Object complexity varied between two and four features. We analyzed electroencephalogram phase coupling as a measure of cortical connectivity in a time interval immediately before a probe stimulus appeared. We assumed that during this time both groups maintained essentially the same images, but that images constructed from their elements would require more neural coupling than images based on a complete percept. Increased coupling between frontal and parietal-to-occipital cortical sources was found for the maintenance of constructed in comparison to nonconstructed objects in the theta, alpha, beta, and gamma frequency bands. A similar pattern was found for an increase in vWM load (2 vs. 4 features) for nonconstructed objects. Under increased construction load (2 vs. 4 features for constructed images), the pattern was restricted to fronto-parietal couplings, suggesting that the fronto-parietal attention network is coping with the higher attentional demands involved in maintaining constructed images, but without increasing the communication with the occipital visual buffer in which the visual representations are assumed to be stored. We conclude from these findings that the maintenance of constructed images in vWM requires additional attentional processes to keep object elements together as a coherent representation.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Palva, Professor Satu
Authors: Ewerdwalbesloh, J. A., Palva, S., Rösler, F., and Khader, P. H.
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
Journal Name:Human Brain Mapping
Publisher:Wiley
ISSN:1065-9471
ISSN (Online):1097-0193
Published Online:13 July 2016

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