Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2001-7-24
pubmed:abstractText
It has recently been demonstrated that a cortical network of visuospatial and oculomotor control areas is active for covert shifts of spatial attention (shifts of attention without eye movements) as well as for overt shifts of spatial attention (shifts of attention with saccadic eye movements). Studies examining activity in this visuospatial network during attentional shifts at a single rate have given conflicting reports about how the activity differs for overt and covert shifts. To better understand how the network subserves attentional shifts, we performed a parametric study in which subjects made either overt attentional shifts or covert attentional shifts at three different rates (0.2, 1.0, and 2.0 Hz). At every shift rate, both overt and covert shifts of visuospatial attention induced activations in the precentral sulcus, intraparietal sulcus, and lateral occipital cortex that were of greater amplitude for overt than during covert shifting. As the rate of attentional shifts increased, responses in the visuospatial network increased in both overt and covert conditions but this parametric increase was greater during overt shifts. These results confirm that overt and covert attentional shifts are subserved by the same network of areas. Overt shifts of attention elicit more neural activity than do covert shifts, reflecting additional activity associated with saccade execution. An additional finding concerns the anatomical organization of the visuospatial network. Two distinct activation foci were observed within the precentral sulcus for both overt and covert attentional shifts, corresponding to specific anatomical landmarks. We therefore reappraise the correspondence of these two precentral areas with the frontal eye fields.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1053-8119
pubmed:author
pubmed:copyrightInfo
Copyright 2001 Academic Press.
pubmed:issnType
Print
pubmed:volume
14
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
310-21
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
A parametric fMRI study of overt and covert shifts of visuospatial attention.
pubmed:affiliation
Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, Maryland 20892, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.