Leveraging visual fidelity to understand the neural mechanisms responsible for remembering images and objects

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PROJECT SUMMARY Our ability to remember the images that we have encountered is remarkable - we can correctly determine whether we have seen an image before after viewing thousands, each only for a few seconds. While we have some understanding of the brain areas involved in supporting ‘visual recognition memory’ (including inferotemporal cortex (IT), perirhinal cortex and the hippocampus), the specific contributions that these brain areas make to visual recognition memory are poorly understood. In addition, very little is known about how the primate brain supports the flexible generalization of rapidly acquired visual memory information – for example, to report whether an object has been seen previously, but perhaps in a different context or configuration. To date, investigations of the neural mechanisms that support visual recognition memory have been limited by the fact that visual memories are stored following single image exposures, whereas the techniques that exist to fit and evaluate models of neural mechanism are most often only effective when applied to data in which the same condition was repeated across many trials. In this proposal, we introduce novel data analysis tools to evaluate single-exposure visual memory models with single-unit data. In these experiments, monkeys perform an object-invariant version of a Mnemonic Similarity task as we record neural responses in temporal lobe structures. In Aim 1, we focus on the contributions of IT and perirhinal cortex to shaping the generalization of single-exposure visual memory behavior. In Aim 2, we focus on entorhinal cortex and the hippocampus. Together, these results will, for the first time, describe the differential contributions of IT, perirhinal cortex, entorhinal cortex and the hippocampus to shaping the generalization of single-exposure visual memory behavior.