Synaptic depression and cortical gain control

LF Abbott, JA Varela, K Sen, SB Nelson - Science, 1997 - science.org
Science, 1997science.org
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 …
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.
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