Adaptation to stimulus statistics in the perception and neural representation of auditory space.
Sensory systems are known to adapt their coding strategies to the statistics of their environment, but little is still known about the perceptual implications of such adjustments. We investigated how auditory spatial processing adapts to stimulus statistics by presenting human listeners and anesthetized ferrets with noise sequences in which interaural level differences (ILD) rapidly fluctuated according to a Gaussian distribution. The mean of the distribution biased the perceived laterality of a subsequent stimulus, whereas the distribution's variance changed the listeners' spatial sensitivity. The responses of neurons in the inferior colliculus changed in line with these perceptual phenomena. Their ILD preference adjusted to match the stimulus distribution mean, resulting in large shifts in rate-ILD functions, while their gain adapted to the stimulus variance, producing pronounced changes in neural sensitivity. Our findings suggest that processing of auditory space is geared toward emphasizing relative spatial differences rather than the accurate representation of absolute position.
Dahmen
Johannes C
JC
Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Parks Road, Oxford OX1 3PT, UK. johannes.dahmen@dpag.ox.ac.uk
Keating
Peter
P
Nodal
Fernando R
FR
Schulz
Andreas L
AL
King
Andrew J
AJ
D000161:Acoustic Stimulation / Q000379:methods; D000200:Action Potentials / Q000502:physiology; D000222:Adaptation, Physiological / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001303:Auditory Cortex / Q000166:cytology; D001307:Auditory Perception / Q000502:physiology*; D005260:Female; D005289:Ferrets; D006801:Humans; D016014:Linear Models; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*; D017711:Nonlinear Dynamics; D011594:Psychometrics; D011601:Psychophysics; D011930:Reaction Time; D013028:Space Perception / Q000502:physiology*; D013997:Time Factors