Gain modulation from background synaptic input

Neuron. 2002 Aug 15;35(4):773-82. doi: 10.1016/s0896-6273(02)00820-6.

Abstract

Gain modulation is a prominent feature of neuronal activity recorded in behaving animals, but the mechanism by which it occurs is unknown. By introducing a barrage of excitatory and inhibitory synaptic conductances that mimics conditions encountered in vivo into pyramidal neurons in slices of rat somatosensory cortex, we show that the gain of a neuronal response to excitatory drive can be modulated by varying the level of "background" synaptic input. Simultaneously increasing both excitatory and inhibitory background firing rates in a balanced manner results in a divisive gain modulation of the neuronal response without appreciable signal-independent increases in firing rate or spike-train variability. These results suggest that, within active cortical circuits, the overall level of synaptic input to a neuron acts as a gain control signal that modulates responsiveness to excitatory drive.

Publication types

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

MeSH terms

  • Action Potentials / physiology*
  • Animals
  • Artifacts
  • Electric Stimulation
  • Genetic Variation
  • Models, Neurological
  • Neural Inhibition / physiology
  • Neural Pathways / cytology
  • Neural Pathways / physiology*
  • Neurons / cytology
  • Neurons / physiology*
  • Organ Culture Techniques
  • Rats
  • Somatosensory Cortex / cytology
  • Somatosensory Cortex / physiology*
  • Synapses / physiology*
  • Synaptic Transmission / physiology*