A Tonic Hyperpolarization Underlying Contrast Adaptation in Cat Visual Cortex

• DOI: 10.1126/science.276.5314.949
• Publication Date: 2002-07-27T09:50:55Z
• Authors: Matteo Carandini; David Ferster
• Keywords: Stimulus (psychology); Tonic (physiology); Hyperpolarization

The firing rate responses of neurons in the primary visual cortex grow with stimulus contrast, variation luminance an image relative to mean luminance. These responses, however, are reduced after a cell is exposed for prolonged periods high-contrast stimuli. This phenomenon, known as contrast adaptation, occurs and not present at earlier stages processing. To investigate cellular mechanisms underlying cortical intracellular recordings were performed cats, effects stimulation studied. Surprisingly, adaptation barely affected stimulus-driven modulations membrane potential cells. Moreover, it did produce sizable changes resistance. major effect evident both presence absence stimulus, was tonic hyperpolarization. Adaptation affects class synaptic inputs, most likely excitatory nature, that exert influence on