Rosie Cowell (UMass Psychological and Brain Sciences) will be presenting Do amnesics forget because old things look new or because new things look old? in the NSB Seminar Series in 222 Morrill II at 4 p.m. Wednesday, February 25. Everyone is welcome – the abstract is below.
Abstract: I will describe a computational model of object recognition memory in perirhinal cortex (PRC) that provides a novel account of why damage to this MTL structure causes individuals to forget. The theory challenges the widely held assumption that the MTL is primarily a memory region. According to the theory, PRC is not a module for object memory, as assumed in most theories of amnesia, but rather a brain region that stores representations of the conjunctions of visual features possessed by complex objects. These representations allow PRC to engage in hyper-specific perception, enabling it to distinguish between particular objects that have been seen before (e.g., my blue Honda with a dent in the side) versus ones that have never been seen before (e.g., a blue Honda I have never seen before). It is this facility with hyper-specific perception that underlies the role of PRC in object memory. The model accounts for the classic findings concerning impaired recognition memory following perirhinal cortex lesions. In addition, it makes novel predictions, for example that brain damage causes a subject to forget not because familiar objects appear new, but because new objects appear familiar. I present simulation results demonstrating this novel prediction, along with findings from rats and humans that provide support for it.