Mark Van Rossum (School of Informatics, Institute for Adaptive and Neural Computation, University of Edinburgh, UK)
Abstract:The strength of the synapses in the brain are presumably continuously subject to increases and decreases as the result of ongoing learning processes. This realization allows one to approximate the synaptic weight evolution as a stochastic process. This has been used to find fundamental limits of storage. Recently we introduced a synaptic information capacity measure based on Shannon information (Barrett and van Rossum '08). We use this to find the optimal weight dependent learning rules. We find that soft-bound learning rules are better than hard bound rules, and show a biophysical model that gives rise to such softbounds. Finally we discuss the role of plasticity in disease and mental retardation.