Optimal properties of analog perceptrons with excitatory weights

PLoS Comput Biol. 2013;9(2):e1002919. doi: 10.1371/journal.pcbi.1002919. Epub 2013 Feb 21.

Abstract

The cerebellum is a brain structure which has been traditionally devoted to supervised learning. According to this theory, plasticity at the Parallel Fiber (PF) to Purkinje Cell (PC) synapses is guided by the Climbing fibers (CF), which encode an 'error signal'. Purkinje cells have thus been modeled as perceptrons, learning input/output binary associations. At maximal capacity, a perceptron with excitatory weights expresses a large fraction of zero-weight synapses, in agreement with experimental findings. However, numerous experiments indicate that the firing rate of Purkinje cells varies in an analog, not binary, manner. In this paper, we study the perceptron with analog inputs and outputs. We show that the optimal input has a sparse binary distribution, in good agreement with the burst firing of the Granule cells. In addition, we show that the weight distribution consists of a large fraction of silent synapses, as in previously studied binary perceptron models, and as seen experimentally.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Computer Simulation
  • Mice
  • Models, Neurological*
  • Nerve Fibers / physiology
  • Neural Networks, Computer*
  • Neuronal Plasticity / physiology
  • Purkinje Cells / physiology
  • Synapses / physiology

Grants and funding

This work has been supported by the Agence Nationale de la Recherche, grant ANR-08-SYSC-005 and by the Swiss National Science Foundation, grant PA00P3_139703. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.