All-night sleep EEG and artificial stochastic control signals have similar correlation dimensions.

EEG signals have been considered to be generated either by stochastic processes or by non-linear deterministic systems exhibiting chaotic behavior. To address this problem, the correlation dimension of the EEG was computed and compared to the correlation dimension of an artificial signal with identical power spectrum. By using a new type of personal super computer we were able for the first time to calculate the correlation dimension for the sleep episode of an entire night as well as for the corresponding artificial signal. The correlation dimension was high in episodes of rapid eye movement (REM) sleep, declined progressively within each non-REM sleep episode, and reached a low level at times when EEG slow waves (0.75-4.5 Hz) were dominant. The correlation dimension of the artificial signal and the EEG changed largely in parallel, although on average the values of the artificial signal were 7.3% higher. These results do not support the hypothesis that the sleep EEG is generated by a chaotic attractor.

[1]  GOTTFRIED MAYER‐KRESS AND,et al.  Dimensionality of the Human Electroencephalogram , 1987, Annals of the New York Academy of Sciences.

[2]  Floris Takens,et al.  DETECTING NONLINEARITIES IN STATIONARY TIME SERIES , 1993 .

[3]  Anton Gunzinger,et al.  Architecture and realization of a multi signal processor system , 1992, [1992] Proceedings of the International Conference on Application Specific Array Processors.

[4]  F. Takens.  Detecting strange attractors in turbulence , 1981 .

[5]  F. H. Lopes da Silva,et al.  Chaos or noise in EEG signals , 1995 .

[6]  A. Provenzale,et al.  Finite correlation dimension for stochastic systems with power-law spectra , 1989 .

[7]  A. Gunzinger,et al.  Correlation Dimension of the Human Sleep Electroencephalogram: Cyclic Changes in the Course of the Night , 1994, The European journal of neuroscience.

[8]  James Theiler,et al.  Estimating fractal dimension , 1990 .

[9]  A. Gunzinger,et al.  Estimation of the Correlation Dimension of All-Night Sleep EEG Data with a Personal Super Computer , 1994 .

[10]  A. Rechtschaffen,et al.  A manual of standardized terminology, technique and scoring system for sleep stages of human subjects , 1968 .

[11]  David C. Hoaglin,et al.  Applications, basics, and computing of exploratory data analysis , 1983 .

[12]  A Garfinkel,et al.  Nonlinear analysis of EEG sleep states. , 1991, Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology.

[13]  Anton Gunzinger,et al.  Achieving super computer performance with a DSP array processor , 1992, Proceedings Supercomputing '92.

[14]  Floris Takens,et al.  On the numerical determination of the dimension of an attractor , 1985 .

[15]  F. H. Lopes da Silva,et al.  Chaos or noise in EEG signals; dependence on state and brain site. , 1991, Electroencephalography and clinical neurophysiology.

[16]  A. Babloyantz,et al.  Evidence of Chaotic Dynamics of Brain Activity During the Sleep Cycle , 1985 .