Neuronal Adaptations to Environmental Change

Sensory systems face a dilemma: On the one hand it is imperative that sensory information be represented with high fidelity. On the other hand the brain has limited representational resources. The typical compromise is enhanced neuronal representation of frequently encountered stimuli. This enhancement may reflect calibration based on statistics of the sensory environment. We studied calibration as it applies to chromatic processing in the primate visual system. We examined two populations of neurons in primary visual cortex: red-green color-opponent neurons and non-opponent luminance cells. We found that color-opponent neurons, which provide outputs that finely distinguish colors varying around the mean chromaticity of the environment, undergo recalibrations of cone-specific inputs in response to long-term chromatic biases. By contrast, cone inputs to non-opponent neurons, which play no role in chromatic discrimination, remained unchanged. Our findings indicate that recalibration based on environmental statistics is an effective strategy to optimize encoding of sensory information.