Dr. Erik Bloss: Synapse plasticity in learning and disease states

Synapses are the computational subunits of the brain. They allow cell-type specific forms of information flow, permit neurons to compartmentalize electrical and biochemical signals, and undergo rapid structural plasticity during experience. Although Crick suggested spine plasticity was a correlate of memory more than 40 years ago, it has been hard to understand precisely how the plasticity of spines drives cognitive function. We have examined this issue in two contexts: one in which mice are required to learn competing memory traces, and one in which mice are engineered to express mutant amyloid as a model of Alzheimer’s disease (AD). I will present unpublished data that suggest adaptive learning requires spine plasticity in specific cortical neurons, at specific synaptic sites, and in a sex-specific manner. In AD mice, the loss of synapses appears to coincide with interference between memory traces. These results suggest new ways in which plasticity might support memory functions.