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Neuron. 2005 Sep 1;47(5):637-43.

Time course of attention reveals different mechanisms for spatial and feature-based attention in area V4.

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1
Department of Molecular and Cell Biology, Berkeley, California 94720, USA.

Abstract

Attention can facilitate visual processing, emphasizing specific locations and highlighting stimuli containing specific features. To dissociate the mechanisms of spatial and feature-based attention, we compared the time course of visually evoked responses under different attention conditions. We recorded from single neurons in area V4 during a delayed match-to-sample task that controlled both spatial and feature-based attention. Neuronal responses increased when spatial attention was directed toward the receptive field and were modulated by the identity of the target of feature-based attention. Modulation by spatial attention was weaker during the early portion of the visual response and stronger during the later portion of the response. In contrast, modulation by feature-based attention was relatively constant throughout the response. It appears that stimulus onset transients disrupt spatial attention, but not feature attention. We conclude that spatial attention reflects a combination of stimulus-driven and goal-driven processes, while feature-based attention is purely goal driven.

PMID:
16129394
DOI:
10.1016/j.neuron.2005.07.020
[Indexed for MEDLINE]
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