Contrast and luminance adaptation alter neuronal coding and perception of stimulus orientation

• Published in: Nature communications Vol. 10; no. 1; p. 941
• Main Authors: Ghodrati, Masoud, Zavitz, Elizabeth, Rosa, Marcello G. P., Price, Nicholas S. C.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 26.02.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 631/378/116/1925; 631/378/116/2392; 631/378/116/2394; 631/378/2613/1875; 631/378/3917; 9/97; Action Potentials - physiology; Adaptation; Adaptation, Physiological; Adult; Animals; Callithrix - physiology; Coding; Contrast Sensitivity - physiology; Decoding; Female; Firing pattern; Firing rate; Humanities and Social Sciences; Humans; Information processing; Information theory; Male; multidisciplinary; Nervous system; Neural coding; Neurons; Neurons - physiology; Orientation; Orientation, Spatial - physiology; Pattern recognition; Photic Stimulation; Psychophysics; Science; Science (multidisciplinary); Sensory systems; Somatosensory cortex; Time dependence; Visual cortex; Visual Cortex - physiology; Visual discrimination; Visual Perception - physiology; Young Adult
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-08894-8

Sensory systems face a barrage of stimulation that continually changes along multiple dimensions. These simultaneous changes create a formidable problem for the nervous system, as neurons must dynamically encode each stimulus dimension, despite changes in other dimensions. Here, we measured how neurons in visual cortex encode orientation following changes in luminance and contrast, which are critical for visual processing, but nuisance variables in the context of orientation coding. Using information theoretic analysis and population decoding approaches, we find that orientation discriminability is luminance and contrast dependent, changing over time due to firing rate adaptation. We also show that orientation discrimination in human observers changes during adaptation, in a manner consistent with the neuronal data. Our results suggest that adaptation does not maintain information rates per se, but instead acts to keep sensory systems operating within the limited dynamic range afforded by spiking activity, despite a wide range of possible inputs. Sensory systems produce stable stimulus representations despite constant changes across multiple stimulus dimensions. Here, the authors reveal dynamic neural coding mechanisms by testing how coding of one dimension (orientation) changes with adaptations to other dimensions (luminance and contrast).