Recall requirements can drastically modulate working memory representations in human visual cortex
Wed—HZ_10—Talks7—7104
Presented by: Giuliana M. Giorjiani
Visual working memory allows for temporary storage of relevant information to support adaptive behavior. Prior fMRI studies investigating passive storage have decoded mnemonic information from activity patterns in early visual cortex (EVC). Given that stored information is ultimately used to accomplish specific tasks, might EVC be involved during recall? Here, we manipulated recall requirements in an orientation memory task to investigate how adaptive behavior impacts EVC representations during recall. Specifically, we wanted to dissociate the roles of visual input, motor output, and online monitoring. To report a remembered orientation, participants (1) used “method-of-adjustment” button presses to rotate a thin dial on the screen, (2) viewed a “matched replay” of a pre-recorded response, and indicated a clockwise or counter-clockwise offset of the final dial orientation, (3) viewed a “mismatched replay”, i.e., a pre-recorded response to a random orientation, pressing a button if the dial crossed the remembered orientation, and (4) used button presses to rotate an “invisible dial” . We uncovered a drastic increase in decoding of the target orientation during recall when the remembered orientation matched the final dial orientation (“method-of-adjustment” and “matched replay” conditions). This implies that visual input alone (a rotating dial with final orientation unrelated to the remembered orientation, as in “mismatch replay”), motor output alone (high during “method-of-adjustment”, low during “matched replay”), or online monitoring alone (required during “mismatched replay”) cannot account for task-relevant feature decoding in EVC during recall. Our findings suggest amplified information in EVC when mnemonic contents match sensory input during recall.
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