Flexible Object-Label Associations Following Rapid Perceptual Learning in Patients with Hippocampal Damage

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Ariana Giuliano^1,2 (agiuliano@research.baycrest.org), Taneisha Heikurinen^2,3, Karen Joseph², Asaf Gilboa^1,2; ¹University of Toronto, Psychology Department, ²Rotman Research Institute, ³York University

Hippocampal damage is traditionally thought to impair conscious, flexible memory (declarative), while leaving intact non-conscious, inflexible memory (nondeclarative) such as perceptual learning following extensive repetition. Recently, Squire et al. (PNAS, 2021) trained patients with hippocampal damage on a one-shot perceptual learning of black and white, ambiguous images (Mooney figures), and showed that correct naming of disambiguated images was retained even months after learning. The declarative memory output (naming previously ambiguous images) and the rapid rate of acquisition led us to speculate that these new representations could also be flexible. We adapted the encoding phase of Squire et al.’s study by presenting 3 Mooney exemplars of each category (e.g., if the target item was a giraffe image, our participants were asked to name 3 different ambiguous images of giraffes). Patients with hippocampal damage and healthy matched controls named the Mooney figures and were then shown either an intact version of the image (disambiguated condition), or a new, unrelated image. Images from the same category belonged to the same condition. During testing (1 and 7 days post-encoding), participants named new Mooney figures from the previously presented categories, including the ones from Squire et al.’s study. Accurate naming would require the generalization of perceptual learning, extending the labels to new items. We found that both controls and patients showed evidence of generalization, with improved naming accuracy for related, but never seen before items. The ability to abstract and generalize what they learned suggests that perceptual learning may be accomplished by rapid cortical integration.

Topic Area: LONG-TERM MEMORY: Other