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Anna Blumenthal, Bobby Stojanoski, Chris Martin, Rhodri Cusack, Stefan K�hler; Representational similarity analysis of category-related recognition-memory signals in the human medial temporal lobe. Journal of Vision 2016;16(12):255. doi: https://doi.org/10.1167/16.12.255.
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© ARVO (1962-2015); The Authors (2016-present)
Neuropsychological studies in patients and functional neuroimaging work have established that perceptual representations of complex objects in the visual ventral stream are shaped by semantic category membership. Whereas the categorical structure of these representations has been well characterized in the context of perceptual tasks, much less is known about the organization of corresponding memory signals, specifically in the medial aspects of the temporal lobe (MTL), which includes the perirhinal, parahippocampal, and entorhinal cortices, as well as the hippocampus. These structures have distinct patterns of connectivity to occipito-temporal and ventrolateral temporal cortex, and are thought to be important for both visual perception and memory. In the current study, we used high resolution fMRI, in combination with multi-voxel pattern analysis, to examine representational similarities in distributed patterns of activity in the MTL during memory judgements for images of real-world objects. Specifically, participants performed a continuous recognition memory task on visually presented objects from 12 different categories, which were matched for recognition accuracy. On each trial, their task was to determine whether the object presented was new (1st presentation) or had been encountered before (2nd presentation). Our primary goal for the analyses of the fMRI data was to characterize representational similarities in memory signals, i.e. in differences between activity patterns for the 1st as compared to 2nd presentation of items from the various categories examined. Preliminary results show evidence for category-specific representations across the different structures that comprise the MTL. This suggests that category structure is differentially preserved in recognition-memory signals in MTL structures, offering support for the notion that its influence extends beyond perceptual representation.
Meeting abstract presented at VSS 2016
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