Learning neural dynamics through instructive signals

Abstract

Rapid learning is essential for flexible behavior, but its basis in the brain remains unknown. Here we introduce the PRISM plasticity rule, a unifying mechanistic model of three well-established, fast-acting synaptic plasticity rules--in hippocampus, cerebellum and mushroom body--which relies exclusively on pre-synaptic activity and an "instructive signal" from another brain area. Using a multi-region network model we show that guiding PRISM plasticity with instructive signals enables the network to quickly learn extremely flexible nonlinear dynamics underlying behaviorally relevant computations, as well as to emulate unknown external system dynamics from real-time error signals, which we demonstrate with comprehensive simulations supported by exact mathematical theory. Thus, PRISM plasticity guided by instructive signals is well-suited to rapidly learn general-purpose neural computations--in contrast to canonical Hebbian rules. Finally, we show how including this plasticity rule in artificial learning algorithms can solve long-range temporal credit assignment, a long-standing challenge in machine learning. HighlightsO_LIPRISM (PResynaptic and Instructive Signal-Mediated) plasticity--a unifying mechanistic model of three fast-acting plasticity rules in hippocampus, cerebellum, and mushroom body. C_LIO_LIMathematical theory inspired by Support Vector Machine exactly predicts the dynamics learned in a network model through PRISM plasticity. C_LIO_LIExamples of learning nonlinear dynamics in a single shot via sparse instructive signals or from real-time error signals. C_LIO_LIMachine-learning application of instructive signals and PRISM plasticity to solve the long-range temporal credit assignment problem. C_LI