Department of Electrical Engineering, Technion, Israel
Friday 30 May 2008
Seminar Room B10 (Basement)
Alexandra House, 17 Queen Square, London, WC1N 3AR
Optimal Real Time Dynamic State Estimation by Neural Networks Based on Spike Train Decoding
A key requirement facing organisms acting in uncertain dynamic environments is the real-time estimation and prediction of external events. While it is becoming evident that organisms employ exact or approximate Bayesian statistical calculations for these purposes, it is far less clear how these putative computations are implemented by neural networks in a strictly dynamic setting. In this work we make use of mathematical tools from the theory of continuous time point process filtering, and show how optimal real-time state estimation and prediction may be implemented in a general setting using simple recurrent neural networks. The framework is applicable to many situations of common interest, including noisy observations, non-Poisson spike trains (incorporating adaptation), multisensory integration and state prediction. The optimal network properties are shown to relate to the statistical structure of the environment, and the benefits of adaptation are studied and explicitly demonstrated. Finally, we recover several existing results as appropriate limits of our general setting.