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.
Original language | English (US) |
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Pages (from-to) | 637-643 |
Number of pages | 7 |
Journal | Neuron |
Volume | 47 |
Issue number | 5 |
DOIs | |
State | Published - Sep 1 2005 |
Bibliographical note
Funding Information:This work was supported by grants to J.L.G. from the NEI and NIMH. We thank James Mazer for development of the neurophysiology software suite; and James Mazer, Stephen David, and Kate Gustavsen for advice on experimental design and data analysis.