Relating information capacity to a biophysical model for blowfly photoreceptors

Photoreceptors measure and communicate information about visual stimuli to other neurons. In this process, the visual signal is converted between many di!erent physical states. We present a communication channel model that describes transmission and degradation of the visual signal in the blow#y photoreceptor cell. The model is a cascade of linear systems and noise sources; these elements are derived from fundamental principles when possible, and parameters of the model are estimated from physiological data. We compute capacity and bit-energy using the model. Our results indicate that photon shot noise and channel noise are the dominant noise sources in blow#y phototransduction. ( 2000 Elsevier Science B.V. All rights reserved.