Increased activity in human visual cortex during directed attention in the absence of visual stimulation

Kastner, S., Pinsk, M. A., De Weerd, P., Desimone, R., & Ungerleider, L. G. (1999)

Neuron, 22(4), 751-761.


When subjects direct attention to a particular location in a visual scene, responses in the visual cortex to stimuli presented at that location are enhanced, and the suppressive influences of nearby distractors are reduced. What is the top-down signal that modulates the response to an attended versus an unattended stimulus? Here, we demonstrate increased activity related to attention in the absence of visual stimulation in extrastriate cortex when subjects covertly directed attention to a peripheral location expecting the onset of visual stimuli. Frontal and parietal areas showed a stronger signal increase during this expectation than did visual areas. The increased activity in visual cortex in the absence of visual stimulation may reflect a top-down bias of neural signals in favor of the attended location, which derives from a fronto-parietal network.

Contribution to the field

This paper shows the fMRI correlate of attentional bias in extrastriate visual cortex, but additionally uncovered much stronger activity in fronto-parietal cortex. Hence, the paper provided one of the first whole brain views of attention, yielding the hypothesis that fronto-parietal cortex was (in the task used) the source of the biasing signal. This paper has been especially influential in the fMRI community, but is also compatible with neurophysiological work in the field of attention and receives significant citations from that field as well.

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