Stimulus onset quenches neural variability: a widespread cortical phenomenon

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Neural responses are often analyzed by mean firing rate, but trial-to-trial variability is also significant.
• Previous research focused on how stimuli affect mean neural responses, with less attention to response variability.

Purpose of the Study:

• To investigate the effect of stimulus onset on neural response variability across different cortical areas.
• To determine if changes in neural variability are a general property of cortical processing.

Main Methods:

• Analysis of 13 extracellular and 1 intracellular neural recording datasets from multiple cortical areas in monkeys and cats.
• Measurement of neural variability in single-neuron spiking, membrane potential, and correlated spiking activity.
• Utilized 96-electrode arrays for correlated spiking variability measurements.

Main Results:

• Stimulus onset consistently decreased neural variability in all recorded datasets.
• This reduction in variability occurred irrespective of changes in the mean firing rate.
• Variability decline was observed across different recording types (membrane potential, single-unit spiking, multi-unit activity) and states (awake, behaving, anesthetized).

Conclusions:

• Stimulus onset induces a widespread decline in neural variability across cortical areas.
• This phenomenon suggests that cortical circuits are stabilized by input, a general property of the cortex.
• Understanding variability changes is crucial for a comprehensive view of neural responses to stimuli.