Attention-Locked Computation with Chaotic Neural Nets

Abstract We review a neural network model based on chaotic dynamics [Babloyantz & Louren co , 1994, 1996] and provide a detailed discussion of its biological and computational relevance. Chaos can be viewed as a \reservoir" containing an innite,number of unstable periodic orbits. In our approach, the periodic orbits are used as coding devices. By considering a large enough number of them, one can in principle expand the information processing capacity of small or moderate-size networks. The system is most of the time in an undetermined state characterized by a chaotic attractor. Depending on the type of an external stimulus, the dynamics is stabilized into one of the available periodic orbits, and the system is then ready to process information. This corresponds to the system being driven into an \attentive" state. We show that, apart from static pattern processing, the model is capable of dealing with moving stimuli. We especially consider in this paper the case of transient visual stimuli, which has a clear biological relevance. The advantages of chaos over more regular regimes are discussed. Keywords: Chaos; Computation; Attention; Spatiotemporal Dynamics; Neural Networks; Cortical Layers; Processing of Changing Visual Stimuli 2