Adaptation to direction statistics modulates perceptual discrimination.
Perception depends on the relative activity of populations of sensory neurons with a range of tunings and response gains. Each neuron's tuning and gain are malleable and can be modified by sustained exposure to an adapting stimulus. Here, we used a combination of human psychophysical testing and models of neuronal population decoding to assess how rapid adaptation to moving stimuli might change neuronal tuning and thereby modulate direction perception. Using a novel motion stimulus in which the direction changed every 10 ms, we demonstrated that 1,500 ms of adaptation to a distribution of directions was capable of modifying human psychophysical direction discrimination performance. Consistent with previous reports, we found perceptual repulsion following adaptation to a single direction. Notably, compared with a uniform adaptation condition in which all motion directions were equiprobable, discrimination was impaired after adaptation to a stimulus comprising only directions ± 30-60° from the discrimination boundary and enhanced after adaptation to the complementary range of directions. Thus, stimulus distributions can be selectively chosen to either impair or improve discrimination performance through adaptation. A neuronal population decoding model incorporating adaptation-induced repulsive shifts in direction tuning curves can account for most aspects of our psychophysical data; however, changes in neuronal gain are sufficient to account for all aspects of our psychophysical data.
Department of Physiology, Monash University, Clayton, Victoria, Australia. nicholas.price@monash.edu
Nicholas S C
NS
Price
Danielle L
DL
Prescott
D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D004192:Discrimination, Psychological / Q000502:physiology*; D005260:Female; D005366:Figural Aftereffect / Q000502:physiology; D006801:Humans; D008297:Male; D008959:Models, Neurological; D015233:Models, Statistical; D009039:Motion Perception / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics / Q000379:methods*; D013269:Stochastic Processes