ROLE OF ITINERANCY AMONG ATTRACTORS AS DYNAMICAL MAP IN DISTRIBUTED CODING SCHEME

A basic frame, based on which certain features of sensory stimuli can be extracted systematically in a distributed coding scheme, has not be en clarified yet. This paper proposes that the basic frame can be a dy namical map represented by itinerancy among attractors. Features of en tities are encoded by attractors of neural networks. Relations between the features in each modality are mapped on dynamical links between t he attractors in each network relevant to each modality. The itinerant states, in which the network dynamic state itinerates chaotically or cyclically among the attractors, can work as dynamical maps. The recog nition of features is carried out by a phase transition from an itiner ant state to a constituent attractor. The phase transition is induced by a short-term synaptic change based on the Hebbian rule under applic ation of a relevant stimulation. A theta-like global oscillation is ne cessary for self-organized formation of the chaotically itinerant stat e. (C) 1997 Elsevier Science Ltd.