White Noise Background Improves Tone Discrimination by Suppressing Cortical Tuning Curves

Cell Rep. 2019 Nov 12;29(7):2041-2053.e4. doi: 10.1016/j.celrep.2019.10.049.

Abstract

The brain faces the difficult task of maintaining a stable representation of key features of the outside world in noisy sensory surroundings. How does the sensory representation change with noise, and how does the brain make sense of it? We investigated the effect of background white noise (WN) on tuning properties of neurons in mouse A1 and its impact on discrimination performance in a go/no-go task. We find that WN suppresses the activity of A1 neurons, which surprisingly increases the discriminability of tones spectrally close to each other. To confirm the involvement of A1, we optogenetically excited parvalbumin-positive (PV+) neurons in A1, which have similar effects as WN on both tuning properties and frequency discrimination. A population model suggests that the suppression of A1 tuning curves increases frequency selectivity and thereby improves discrimination. Our findings demonstrate that the cortical representation of pure tones adapts during noise to improve sensory acuity.

Keywords: auditory cortex; awake electrophysiological recordings; background noise; decision making; optogenetics; parvalbumin interneurons; population coding; sensory processing; sensory-driven behavior.

MeSH terms

  • Acoustic Stimulation
  • Animals
  • Auditory Cortex / physiology*
  • Auditory Perception / physiology*
  • Cell Line
  • Evoked Potentials, Auditory / physiology*
  • Mice
  • Neurons / cytology
  • Neurons / metabolism*
  • Noise*