Robert Woodry¹, Jonathan Winawer¹, Serra Favila²; ¹New York University, ²Brown University

Sensory cortex exhibits activity patterns during long-term memory retrieval similar to those during encoding. This memory reactivation in primary visual cortex is especially robust for items that were highly practiced in an associative learning task requiring repeated, precise judgments (Woodry, Curtis, Winawer, 2024). Here we examined the role of visual cortex in a more natural, one-shot memory paradigm. Building on a pilot fMRI study (n=5) by Favila and Winawer (VSS 2020), we increased the sample size (n=13) and conducted new analyses of an experiment in which participants encountered 480 object images across three interleaved tasks: encoding, recognition, and spatial recall. During encoding scans, peripheral objects appeared at one of four polar angles while subjects maintained central fixation and judged whether the object was bigger/smaller than a shoebox. During recognition scans, either the same objects or lures were presented centrally while subjects made old/new judgments. During spatial recall scans, subjects viewed old objects centrally and indicated the polar angle of the object at encoding. We observed spatially tuned responses in visual cortex, including V1, that were relevant for encoding success, recognition, and recall. First, at encoding, V1 responses were larger and more sharply tuned for objects whose location was successfully recalled later. Second, spatially tuned responses were evoked in visual cortex during successful recognition, even though the items had only been viewed once and location wasn’t probed. Moreover, spatial tuning in visual cortex during recognition was poor for objects later forgotten (incorrect spatial judgment), indicating that the spatially tuned recognition responses were behaviorally relevant. Third, when aligning to the reported location during recall, we observed spatially tuned responses for both remembered and forgotten objects. These findings show how the properties of visual cortex activation track memory behavior during encoding, recognition, and recall, even for single shot memory.