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Khena Swallow, Tal Makovski, Yuhong Jiang; Detecting goal-relevant events boosts activity in primary visual cortex. Journal of Vision 2011;11(11):241. doi: 10.1167/11.11.241.
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© ARVO (1962-2015); The Authors (2016-present)
Several recent behavioral studies suggest that target detection triggers more than an attentional response to the target itself. Rather, it appears that perceptual processing of information that is presented at the same time as a target is enhanced. To test this possibility, we used fMRI to measure how activity in visual cortical areas is modulated by the presence of auditory targets and task-relevant visual images. Participants were asked to perform two tasks at the same time: encode centrally presented images of faces and scenes into memory for a later memory test, and press the button whenever a beep of a certain frequency (target beep) is played over the headphones (no response was made when a distractor beep of a different frequency was played). Activity in V1 increased more when visual images were presented at the same time as target beeps than when they were presented at the same time as distractor beeps. Surprisingly, V1 responded more to auditory targets than to auditory distractors even when no images were presented. This increase in activity was observed in all of V1, including parts representing peripheral portions of the visual field. However, the increase appeared to diminish in higher visual areas such as the fusiform gyrus and the parahippocampal gyrus. A second experiment confirmed that the greater response of V1 to targets than to distractors is not due to cross-modal interactions between auditory and visual cortices. In line with several recent reports, it appears that activity in primary visual cortex reflects more than visual input and attentional selection processes. Instead, our data suggest that primary visual cortex is additionally sensitive to the need to make a cognitive or motor response to goal-relevant events.
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