» fracdyn » neurodyn » Introduction

These pages have been designed as a source of discussion regarding the chaotic aspects of brain dynamics. Most of the information presented has been gleaned from papers discussing and interpreting electroencephalogram readings from both human and rodent brains. These experiments are significant for a variety of reasons; the main ones we have considered are those with implications in the field of brain state modeling. This is the most direct application of the EEG findings. These new models for brain activity suggest a need for the revamping of conceptions of perceptual processes and overall brain functioning. The new models may or may not replace existing models such as the ART neural model, or the connectionist models of neural nets; certainly the older neural-net models will have to be modified and/or fleshed out to meet with the explanatory power of these new models. The nature of the findings are these:
(a) there is global spacio-temporal structure to brain states measurable by the EEG;
(b) these states when studied in the olfactory bulb show structural transformation with respect to conditioned and novel stimuli;
(c) stable state structure (quiescent EEG) within the olfactory bulb corresponds to a chaotic attractor with dimension between 4 and 7;
(d) dynamical structure of the EEG readings has a period unique to each conditioned stimulus; and
(e) novel stimuli produce an EEG reading corresponding to higher-dimension chaos with respect to the `background' chaotic attractors.
Chris King, who has written extensively on the subject of brain chaos and its implications, says of olfactory response to stimuli,
On inhalation a transition occurs from low level chaos. . . to a trajectory which in the case of a familiar odor will settle into one of several periodic orbits, but in the case of a new odor will avoid existing periodic attractors hunting chaotically until a new periodic attractor is established over time, forming a both a new familiarized response and a new symbol. [1]
This quotation gives an introduction to one of the main focuses of this website: the role of chaos. We will also be discussing some significant features of chaotic dynamics as a way of understanding global brain function, as well as some discussion of chaotic dynamics on the local scale.

[1] Chris King
Fractal and Chaotic Dynamics in Nervous Systems
Progress in Neurobiology. vol.36, pp.279-308. 1991

Last modified: Tue Jan 4 21:19:24 PST 2000