Abstract
The formation of enduring visual memory requires a consolidation process, in which temporarily maintained visual information is transferred to the neocortex for more permanent storage. Yet, how consolidated information is organized and retained in the neocortex remains a mystery. Here, we examine a participant’s perceptual and memory functions following resection of the left posterior parahippocampal cortex to investigate the contribution of category-sensitive neocortex to the consolidation of category-specific memory. The participant was first admitted for intracranial electroencephalography (iEEG) monitoring to localize the source of seizure. Before and during this procedure, we tested the participant’s ability in the perceptual categorization of objects, faces, scenes, and animals under different levels of embedded noise in an image. Three months after surgical treatment, we tested the participant’s perceptual categorization ability again. We found that the participant’s perceptual discriminability for noisy scene images was selectively compromised despite intact ability to identify a no-noise scene image. Retrospective inspection of the iEEG data based on electrodes within the resected brain tissue also showed selective information coding for scenes during perceptual categorization, suggesting that the resected tissue contained the parahippocampal place area (PPA). During the one-year post-surgery visit, we then tested the participant’s recognition memory for different visual categories, including scenes, faces, and objects, both immediately following the study of 80 images for a given category and after an 18-hour delay on the next day. By comparing the participant’s performance at these timepoints (∆d’ = immediate - delayed), we found the participant showed greater forgetting of scenes (∆d’ = 1.09), as compared with faces (∆d’ = 0.56) and objects (∆d’ = 0.57). Collectively, by revealing this category-selective deficit in memory consolidation following the resection of category-sensitive neocortex, these data suggest that novel visual experiences are remembered in a category-specific manner in the neocortex.