January 20, 2021

History-driven modulations of population codes in early visual cortex during visual search

To find important objects, we must focus on our goals, ignore distractions, and take our changing environment into account. This is formalized in models of visual search whereby goal-driven, stimulus-driven and history-driven factors are integrated into a priority map that guides attention. History is invoked to explain behavioral effects that are neither wholly goal-driven nor stimulus-driven, but whether history likewise alters goal-driven and/or stimulus-driven signatures of neural priority is unknown. We measured fMRI responses in human visual cortex during a visual search task where trial history was manipulated (colors switched unpredictably or repeated). History had a near-constant impact on responses to singleton distractors, but not targets, from V1 through parietal cortex. In contrast, history-independent target enhancement was absent in V1 but increased across regions. Our data suggest that history does not alter goal-driven search templates, but rather modulates canonically stimulus-driven sensory responses to create a temporally-integrated representation of priority.

 bioRxiv Subject Collection: Neuroscience

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