Synaptic depression and cortical gain control

Science. 1997 Jan 10;275(5297):220-4. doi: 10.1126/science.275.5297.221.


Cortical neurons receive synaptic inputs from thousands of afferents that fire action potentials at rates ranging from less than 1 hertz to more than 200 hertz. Both the number of afferents and their large dynamic range can mask changes in the spatial and temporal pattern of synaptic activity, limiting the ability of a cortical neuron to respond to its inputs. Modeling work based on experimental measurements indicates that short-term depression of intracortical synapses provides a dynamic gain-control mechanism that allows equal percentage rate changes on rapidly and slowly firing afferents to produce equal postsynaptic responses. Unlike inhibitory and adaptive mechanisms that reduce responsiveness to all inputs, synaptic depression is input-specific, leading to a dramatic increase in the sensitivity of a neuron to subtle changes in the firing patterns of its afferents.

Publication types

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

MeSH terms

  • Action Potentials
  • Animals
  • Electric Stimulation
  • In Vitro Techniques
  • Models, Neurological*
  • Neuronal Plasticity
  • Neurons / physiology*
  • Neurons, Afferent / physiology
  • Rats
  • Synapses / physiology*
  • Synaptic Transmission*
  • Visual Cortex / physiology