Adaptive rescaling maximizes information transmission

Adaptation is a widespread phenomenon in nervous systems, providing flexibi lity to function under Varying external conditions. Here, we relate an adap tive property of a sensory system directly to its function as a carrier of information about input signals. We show that the input/output relation of a sensory system in a dynamic environment changes with the statistical prop erties of the environment. Specifically, when the dynamic range of inputs c hanges, the input/output relation rescales so as to match the dynamic range of responses to that of the inputs. We give direct evidence that the scali ng of the input/output relation is set to maximize information transmission for each distribution of signals. This adaptive behavior should be particu larly useful in dealing with the intermittent statistics of natural signals .