Testing a Perceptual Theory of Amnesia with fMRI: Perceptual Interference Disrupts Neural Signatures of Familiarity in Visual Cortex

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• Dr Rosie Cowell - Computational Memory & Perception Lab, Psychology, Univ. of Massachusetts Amherst
• Monday 22 June 2015, 13:00-14:00
• Kenneth Craik Room, Craik Marshall Building, Downing Site, Cambridge.

If you have a question about this talk, please contact Lorraine Coulson.

One theory of amnesia assumes that (1) in the absence of medial temporal lobe (MTL) structures, familiarity judgements are based upon representations of simple visual features in posterior visual cortex, and (2) these representations are susceptible to perceptual interference. Using an incidental 1-back repetition detection task during fMRI, we presented a series of object photographs to assess whether perceptual interference disrupted neural signatures of novelty. Novelty was indexed by repetition reduction (RR) of the BOLD signal. In posterior visual cortex, we expected to see less RR at the end of the series – after perceptual interference – than at the beginning; this would indicate that perceptual interference disrupts the neural signature of novelty in these brain regions. In the ‘high interference’ condition, interfering objects presented in the middle of the series were perceptually similar to those at the beginning and end (for which RR was measured). In the ‘low interference’ condition, interfering objects were dissimilar. Consistent with the theory, RR was reduced by interference in a posterior visual region, during high interference relative to low interference series of objects.

This talk is part of the Behavioural and Clinical Neuroscience Seminars series.

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