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Poster E in Poster Session E: Thursday, August 6, 10:30 am – 12:15 pm, Kimmel Center, Shorin & Rosenthal Rooms

Neural priority maps encode behavioral relevance independently across multiple attended locations

Amelia H. Harrison¹, Daniel Thayer¹, Thomas Christopher Sprague¹; ¹University of California, Santa Barbara

Presenter: Amelia H. Harrison

Behavioral studies often demonstrate costs to dividing attention across multiple simultaneously relevant locations, yet it remains unclear whether these costs reflect degraded early sensory representations or limitations at later processing stages. Neural priority maps — retinotopically organized representations of stimulus salience and behavioral relevance — provide an ideal substrate for investigating this question. If relevance signals are capacity-limited, map activation should scale inversely with the number of attended locations; if relevance is encoded independently, activation should remain equivalent regardless of how many locations are concurrently task-relevant. We measured fMRI BOLD responses while participants performed a selective attention task at fixation, one cued location, or two simultaneously cued locations, with stimulus salience equated across conditions. Using spatial IEMs across retinotopic cortex, relevance-related map activation was statistically equivalent for one versus two attended locations across all regions and stimulus contrasts — indicating that task relevance is encoded categorically: once a location is designated as behaviorally relevant, it receives equivalent attentional enhancement regardless of whether another location is simultaneously selected.

Topic Area: Computational Models of Vision & Visual Cortex