Neural processes underlying the temporal allocation of attention

Sherwell, Chase (2011). Neural processes underlying the temporal allocation of attention Honours Thesis, School of Psychology, The University of Queensland.

       
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Author Sherwell, Chase
Thesis Title Neural processes underlying the temporal allocation of attention
School, Centre or Institute School of Psychology
Institution The University of Queensland
Publication date 2011-10-12
Thesis type Honours Thesis
Supervisor Associate Professor Ross Cunnington
Total pages 91
Language eng
Subjects 1701 Psychology
Abstract/Summary Orienting attention to the expected time of events speeds responses and enhances the perception of stimuli at the attended time (Griffin, Miniussi, & Nobre, 2001). Temporal orienting is reflected in the modulation of a slow-rising negative potential over the motor cortex, known as the contingent negative variation (CNV). Previous studies have primarily used speeded motor responses to examine temporal orienting effects, making it difficult to disentangle temporal orienting effects from motor or perceptual processes. This thesis studied the effects of temporal orienting on the CNV in the absence of overt motor preparation, in order to examine cortical activity underlying temporal attention independently of motor processes. A novel temporal orienting paradigm was devised using a two-alternative forced-choice discrimination task. Participants judged target Gabor patch stimuli as being rotated clockwise or counter-clockwise in comparison to standard stimuli, and gave delayed verbal responses to avoid motor preparation preceding target onset. The ability to orient attention to the time of target onset was manipulated between blocks, with targets appearing predictably after a short (1000ms) or long (1750ms) interval following standard stimuli, or unpredictably appearing after either interval. Cortical activity was recorded using electroencephalography (EEG). When target onset was predictable, neural activity associated with target processing was enhanced (greater visual N1 component) and participants were more accurate in discerning target orientation. Crucially, the ability to orient attention to an expected time increased CNV amplitude, similar to that seen during motor planning prior to speeded motor responses. Findings suggest that the slow increase in neural activity seen in the CNV, beginning up to 1 s prior to a critical expected event, reflect processes involved in the temporal allocation of attention independent of motor preparation.
Keyword Neural processes
Temporal allocation of attention

 
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Created: Tue, 26 Jun 2012, 15:01:49 EST by Mrs Ann Lee on behalf of School of Psychology