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Awareness-related activity in prefrontal and parietal cortices in blindsight reflects more than superior visual performance

Persaud, Navindra and Davidson, Matthew and Maniscalco, Brian and Mobbs, Dean and Passingham, Richard E. and Cowey, Alan and Lau, Hakwan (2011) Awareness-related activity in prefrontal and parietal cortices in blindsight reflects more than superior visual performance. NeuroImage, 58 (2). pp. 605-611. ISSN 1053-8119. doi:10.1016/j.neuroimage.2011.06.081.

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Many imaging studies report activity in the prefrontal and parietal cortices when subjects are aware as opposed to unaware of visual stimuli. One possibility is that this activity simply reflects higher signal strength or the superior task performance that is associated with awareness. To find out, we studied the hemianope GY who has unilateral destruction of almost all primary visual cortices. He exhibits ‘blindsight’, that is, he claims to have no conscious visual phenomenology (i.e., no visual qualia), for stationary stimuli presented to his right visual field (the blind field), although he can press keys to distinguish between different stimuli presented there. We presented to him a visual discrimination task, and equated performance for stimuli presented to the left or right visual field by presenting low contrast stimuli to his normal (left) field and high contrast stimuli to his blind (right) field. Superior accuracy can be a serious confound, and our paradigm allows us to control for it and avoid this confound. Even when performance was matched, and the signal strength was lower, visual stimulation to the normal (conscious) field led to higher activity in the prefrontal and parietal cortices. These results indicate that the activity in the prefrontal and parietal areas that has been reported in previous studies of awareness is not just due to a (signal strength or performance) confounds. One possibility is that it reflects the superior ‘metacognitive’ capacity that is associated with awareness, because GY was better able to distinguish between his own correct and incorrect responses for stimuli presented to his normal field than to his blind field.

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Mobbs, Dean0000-0003-1175-3772
Additional Information:© 2011 Elsevier Inc. Received 21 January 2011. Revised 23 June 2011. Accepted 27 June 2011. Available online 2 July 2011. NP is supported by a Banting Postdoctoral Research Fellowship from the CIHR and the Federal Government of Canada. HL is supported by the Templeton Foundation (grant number 21569).
Funding AgencyGrant Number
Canadian Institutes of Health Research (CIHR)UNSPECIFIED
Federal Government of CanadaUNSPECIFIED
Templeton Foundation21569
Subject Keywords:Blindsight; Consciousness; Visual perception; Metacognition
Issue or Number:2
Record Number:CaltechAUTHORS:20180305-081344918
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Official Citation:Navindra Persaud, Matthew Davidson, Brian Maniscalco, Dean Mobbs, Richard E. Passingham, Alan Cowey, Hakwan Lau, Awareness-related activity in prefrontal and parietal cortices in blindsight reflects more than superior visual performance, NeuroImage, Volume 58, Issue 2, 2011, Pages 605-611, ISSN 1053-8119, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85087
Deposited On:05 Mar 2018 22:55
Last Modified:15 Nov 2021 20:25

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