Invariant computations in local cortical networks with balanced excitation and inhibition

Nat Neurosci. 2005 Feb;8(2):194-201. doi: 10.1038/nn1391. Epub 2005 Jan 23.


Cortical computations critically involve local neuronal circuits. The computations are often invariant across a cortical area yet are carried out by networks that can vary widely within an area according to its functional architecture. Here we demonstrate a mechanism by which orientation selectivity is computed invariantly in cat primary visual cortex across an orientation preference map that provides a wide diversity of local circuits. Visually evoked excitatory and inhibitory synaptic conductances are balanced exquisitely in cortical neurons and thus keep the spike response sharply tuned at all map locations. This functional balance derives from spatially isotropic local connectivity of both excitatory and inhibitory cells. Modeling results demonstrate that such covariation is a signature of recurrent rather than purely feed-forward processing and that the observed isotropic local circuit is sufficient to generate invariant spike tuning.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Action Potentials / physiology
  • Action Potentials / radiation effects
  • Animals
  • Brain Mapping
  • Cats
  • Cell Count / methods
  • Cholera Toxin / metabolism
  • Computer Simulation*
  • Diagnostic Imaging / methods
  • Immunohistochemistry / methods
  • Models, Neurological
  • Nerve Net / physiology*
  • Neural Inhibition / physiology*
  • Neurons / physiology*
  • Neurons / radiation effects
  • Orientation / physiology
  • Patch-Clamp Techniques / methods
  • Photic Stimulation / methods
  • Synapses / physiology
  • Synaptic Transmission / physiology
  • Synaptic Transmission / radiation effects
  • Visual Cortex / cytology*
  • Visual Cortex / physiology
  • Visual Perception / physiology
  • gamma-Aminobutyric Acid / metabolism


  • gamma-Aminobutyric Acid
  • Cholera Toxin