Abstract
The transitory activity of neuron assemblies has been observed in various areas of animal and human brains. We here highlight some typical transitory dynamics observed in laboratory experiments and provide a dynamical systems interpretation of such behaviors. The transitory dynamics typically observed in the brain seems to appear in high-dimensional systems. A new dynamical systems interpretation for the cortical dynamics is reviewed, cast in terms of high-dimensional transitory dynamics. This interpretation differs from the conventional one, which is usually cast in terms of low-dimensional attractors. We focus our attention on, in particular, chaotic itinerancy, a dynamic concept describing transitory dynamics among “exotic attractors”, or “attractor ruins”. We also emphasize the functional significance of chaotic itinerancy. We further show that Cantor coding can be used to hierarchically embed temporal sequences produced by a chaotic or a random information source. We propose a hypothesis on the possibility of Cantor coding for the formation of episodic memory in the hippocampus and also for the category formation of episodic memory. [Jpn J Physiol 55 Suppl:S9 (2005)]
