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Jiye G. Kim, Emma Gregory, Barbara Landau, Michael McCloskey, Sabine Kastner, Nicholas B. Turk-Browne; Ventral visual selectivity and adaptation in amnesia.. Journal of Vision 2013;13(9):5. doi: 10.1167/13.9.5.
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© ARVO (1962-2015); The Authors (2016-present)
Regions in the ventral visual cortex respond preferentially to particular categories of visual information, such as objects in the lateral occipital cortex (LOC), scenes in the parahippocampal place area (PPA), and faces in the fusiform face area (FFA). However, the role of the medial temporal lobe (MTL) memory system in ventral visual processing remains unknown. To address this issue, we examined the visual cortex of a densely amnesic individual. LSJ is a 62 year-old woman with severe anterograde and retrograde amnesia resulting from herpes encephalitis. High-resolution anatomical MRI revealed that more than 95% of her hippocampus was destroyed bilaterally; she also has extended damage to other MTL and anterior temporal regions, especially on the left. Although LSJ is profoundly impaired on memory tasks (e.g., Wechsler Memory Scale’s General Memory index of <0.1 percentile), her basic sensory and language abilities are spared. We ran several fMRI sessions with LSJ. First, we investigated how MTL damage affects category selectivity in the ventral visual cortex. We conducted functional localizers, using a block design to present a series of stimuli including objects, faces, scenes and scrambled textures. LSJ showed intact object-selective LOC and scene-selective PPA. Face selectivity in FFA was less robust, suggesting a potential role for the MTL in FFA processing. Second, we investigated how MTL damage affects adaptation in the ventral visual cortex, given that the mechanisms underlying this effect remain unsettled. We tested for attenuated responses to blocks where an identical stimulus was repeated multiple times compared to blocks where multiple different stimuli were presented once. Reliable adaptation was found for objects and scenes in LOC and PPA, respectively. Together, these results demonstrate that the MTL may not be vital for category selectivity in the ventral visual cortex and that rapid adaptation effects are not mediated by this memory system.
Meeting abstract presented at VSS 2013
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