Gain Control in the Auditory Cortex Evoked by Changing Temporal Correlation of Sounds.
Natural sounds exhibit statistical variation in their spectrotemporal structure. This variation is central to identification of unique environmental sounds and to vocal communication. Using limited resources, the auditory system must create a faithful representation of sounds across the full range of variation in temporal statistics. Imaging studies in humans demonstrated that the auditory cortex is sensitive to temporal correlations. However, the mechanisms by which the auditory cortex represents the spectrotemporal structure of sounds and how neuronal activity adjusts to vastly different statistics remain poorly understood. In this study, we recorded responses of neurons in the primary auditory cortex of awake rats to sounds with systematically varied temporal correlation, to determine whether and how this feature alters sound encoding. Neuronal responses adapted to changing stimulus temporal correlation. This adaptation was mediated by a change in the firing rate gain of neuronal responses rather than their spectrotemporal properties. This gain adaptation allowed neurons to maintain similar firing rates across stimuli with different statistics, preserving their ability to efficiently encode temporal modulation. This dynamic gain control mechanism may underlie comprehension of vocalizations and other natural sounds under different contexts, subject to distortions in temporal correlation structure via stretching or compression.
Department of Otorhinolaryngology and Head and Neck Surgery.|Graduate Group in Neuroscience.
Ryan G
RG
Natan
Department of Otorhinolaryngology and Head and Neck Surgery.|Graduate Group in Physics.
Isaac M
IM
Carruthers
Department of Otorhinolaryngology and Head and Neck Surgery.
Laetitia
L
Mwilambwe-Tshilobo
Department of Otorhinolaryngology and Head and Neck Surgery.|Graduate Group in Neuroscience.|Graduate Group in Physics.|Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Maria N
MN
Geffen
D000161:Acoustic Stimulation / Q000379:methods; D000200:Action Potentials; D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D004567:Electrodes, Implanted; D016014:Linear Models; D008297:Male; D009474:Neurons / Q000502:physiology*; D017711:Nonlinear Dynamics; D020318:Rats, Long-Evans; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors
adaptation; auditory cortex; electrophysiology; gain control; natural sounds