Abstract:
:Positron emission tomography (PET) measurements of brain blood flow were used to monitor changes in the human primary and secondary somatosensory cortices during the period when somatosensory stimuli were expected. In anticipation of either focal or innocuous touching, or localized, painful shocks, blood flow decreased in parts of the primary somatosensory cortex map located outside the representation of the skin area that was the target of the expected stimulus. Specifically, attending to an impending stimulus to the fingers produced a significant decrease in blood flow in the somatosensory zones for the face, whereas attending to stimulation of the toe produced decreases in the zones for the fingers and face. Decreases were more prominent in the side ipsilateral to the location of the expected stimulus. No significant changes in blood flow occurred in the region of the cortex representing the skin locus of the awaited stimulation. These results are concurrent with a model of spatial attention in which potential signal enhancement may rely on generalized suppression of background activity.
journal_name
Naturejournal_title
Natureauthors
Drevets WC,Burton H,Videen TO,Snyder AZ,Simpson JR Jr,Raichle MEdoi
10.1038/373249a0subject
Has Abstractpub_date
1995-01-19 00:00:00pages
249-52issue
6511eissn
0028-0836issn
1476-4687journal_volume
373pub_type
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