Synaptic information transfer in computer models of neocortical columns

J Comput Neurosci. 2011 Feb;30(1):69-84. doi: 10.1007/s10827-010-0253-4. Epub 2010 Jun 17.

Abstract

Understanding the direction and quantity of information flowing in neuronal networks is a fundamental problem in neuroscience. Brains and neuronal networks must at the same time store information about the world and react to information in the world. We sought to measure how the activity of the network alters information flow from inputs to output patterns. Using neocortical column neuronal network simulations, we demonstrated that networks with greater internal connectivity reduced input/output correlations from excitatory synapses and decreased negative correlations from inhibitory synapses, measured by Kendall's τ correlation. Both of these changes were associated with reduction in information flow, measured by normalized transfer entropy (nTE). Information handling by the network reflected the degree of internal connectivity. With no internal connectivity, the feedforward network transformed inputs through nonlinear summation and thresholding. With greater connectivity strength, the recurrent network translated activity and information due to contribution of activity from intrinsic network dynamics. This dynamic contribution amounts to added information drawn from that stored in the network. At still higher internal synaptic strength, the network corrupted the external information, producing a state where little external information came through. The association of increased information retrieved from the network with increased gamma power supports the notion of gamma oscillations playing a role in information processing.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Brain / anatomy & histology
  • Brain / physiology
  • Computer Simulation*
  • Entropy
  • Humans
  • Information Theory*
  • Models, Neurological*
  • Neocortex / physiology*
  • Nerve Net / cytology
  • Nerve Net / physiology
  • Neurons / classification
  • Neurons / physiology*
  • Spectrum Analysis
  • Synapses / physiology*
  • Time Factors
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / metabolism
  • gamma-Aminobutyric Acid / metabolism

Substances

  • gamma-Aminobutyric Acid
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid