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ERIC Number: EJ906767
Record Type: Journal
Publication Date: 2011-Feb
Pages: 10
Abstractor: As Provided
Reference Count: 0
ISSN: ISSN-0278-2626
Visual Detection and Identification Are Not the Same: Evidence from Psychophysics and fMRI
Straube, Sirko; Fahle, Manfred
Brain and Cognition, v75 n1 p29-38 Feb 2011
Sometimes object detection as opposed to identification is sufficient to initiate the appropriate action. To explore the neural origin of behavioural differences between the two tasks, we combine psychophysical measurements and fMRI, specifically contrasting shape detection versus identification of a figure. This figure consisted of Gabor elements being oriented differently from those in the background. We equalized performance levels for detection and identification by adjusting orientation differences accordingly for each observer. Hence, stimulus saliency was constant for both tasks allowing a differentiation between the activations specific for detection versus identification processes. Identification yielded higher psychophysical thresholds, slower reaction times and increased hemodynamic activations in the lateral-occipital complex (LOC) and an adjacent area in the collateral sulcus (CoS). Additional analysis using cortex-based alignment revealed four voxel-clusters differentially activated by the tasks, situated in the inferior parietal lobe, the precuneus, the anterior cingulum and the medial frontal gyrus. Our results indicate partly separated cortical mechanisms for object detection and identification. (Contains 4 figures and 2 tables.)
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A