Christian Machens, Cold Spring Harbor Laboratory, 3/18/03

Finding the optimal stimulus ensemble online by information maximization

Recent work has shown that neurons are often optimized towards certain statistical properties of an animal's natural environment. Usually, these conclusions have been drawn by a combined analysis of natural stimuli and neural response properties. Alternatively, the stimulus statistics that a given system ``expects'' might be extracted directly from the system in online experiments. We demonstrate the feasibility of this idea in electrophysiological experiments on locust auditory receptor neurons. Using a recently developed algorithm (Phys. Rev. Lett. 88:228104), we adapt the parameters of an initial stimulus ensemble so as to maximize the mutual information between stimulus and neural response. We show that the concept of optimality cannot be treated in isolation but rather depends on further assumptions about the system. Here, we present the optimal stimulus ensemble for the case of a rate code and a spike timing code. [joint work with Tim Gollisch, Olga Kolesnikova, and Andreas V. M. Herz]