The use of nonlinear mathematical dynamics is claimed to be revolutioning some sciences, because deterministic models can be made of unresolved physical and chemical phenomena (e.g., Brownian motion, turbulent flow, etc.). Several laboratories have attempted to apply nonlinear dynamics, th t is, the correlation dimension (D2) to the electroencephalogram of humans. Our laboratory, being skeptical, tested some of their claims on surface potentials in a simple model system, the olfactory bulb). The bulb has the same cell types and intrinsic neurochemistry as neocortex, but has a much simpler and better understood neurophysiology. Algorithms were developed t estimate D2, which led to the conviction that low-dimentional chaos DOES EXIST in the bulb. Using brief epochs and behavioral control, stationarity was observed; by eliminating spurious autocorrelations, linear correlation- integrals were achieved to calculate D2; by studying known chaotic attractors, rules were developed for sampling the attractor. Following thi experience, we now propose to determine whether or not the nonlinear dynamical analyses can be applied to real neocortex. Our first Specific Ai is to evalute D2 during various normal cortical conditions: quiet wakefulness, sleep and event-related reactions. Because of the sensitivity of the D2-meausre and its potential clinical application, Specific Aim 2 is to evalute D2 during known pathological conditions in the cortex: hypernoradrenergic reactivity (hypertension in SHR and renovascular rat models) and hypernoradrenergic innervation (epilepsy in the tottering-mouse model).
Specific Aim 3 is to determine whether or not D2-values are sensitive to therapeutic interventions. If D2 is found to be sensitive to normal and abnormal cortical functioning, then its use can be developed for the diagnosis of cerebral (and perhaps preclinical) pathology and the evaluation of therapies. Because of its process-specific signature, D2 can be used to map anatomical loci which contribute to the singular dynamical system. Furthermore, the integer and fractional portions of D2 have theoretical implications regarding the number of independent variables in t e stationary process and whether or not it may factal. (key words: nonlinea dynamics, chaos, fractals, cerebral cortex, event-related potentials, sleep epilepsy, hypertension, noradrenergic response).

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS027745-03
Application #
3414145
Study Section
Neurology A Study Section (NEUA)
Project Start
1989-08-01
Project End
1994-07-31
Budget Start
1991-08-01
Budget End
1992-07-31
Support Year
3
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Type
Schools of Medicine
DUNS #
074615394
City
Houston
State
TX
Country
United States
Zip Code
77030
Skinner, J E; Molnar, M; Kowalik, Z J (2000) The role of the thalamic reticular neurons in alpha- and gamma-oscillations in neocortex: a mechanism for selective perception and stimulus binding. Acta Neurobiol Exp (Wars) 60:123-42
Skinner, J E; Nester, B A; Dalsey, W C (2000) Nonlinear dynamics of heart rate variability during experimental hemorrhage in ketamine-anesthetized rats. Am J Physiol Heart Circ Physiol 279:H1669-78
Skinner, J E; Molnar, M (1999) Event-related dimensional reductions in the primary auditory cortex of the conscious cat are revealed by new techniques for enhancing the non-linear dimensional algorithms. Int J Psychophysiol 34:21-35
Meyer, M; Rahmel, A; Marconi, C et al. (1998) Stability of heartbeat interval distributions in chronic high altitude hypoxia. Integr Physiol Behav Sci 33:344-62
Meyer, M; Rahmel, A; Marconi, C et al. (1998) Is the heart preadapted to hypoxia? Evidence from fractal dynamics of heartbeat interval fluctuations at high altitude (5,050 m). Integr Physiol Behav Sci 33:9-40
Skinner, J E; Wolf, S G; Kresh, J Y et al. (1996) Application of chaos theory to a model biological system: evidence of self-organization in the intrinsic cardiac nervous system. Integr Physiol Behav Sci 31:122-46
Meyer, M; Marconi, C; Ferretti, G et al. (1996) Heart rate variability in the human transplanted heart: nonlinear dynamics and QT vs RR-QT alterations during exercise suggest a return of neurocardiac regulation in long-term recovery. Integr Physiol Behav Sci 31:289-305
Skinner, J E; Molnar, M; Tomberg, C (1994) The point correlation dimension: performance with nonstationary surrogate data and noise. Integr Physiol Behav Sci 29:217-34
Skinner, J E (1994) The role of the central nervous system in sudden cardiac death: heartbeat dynamics in conscious pigs during coronary occlusion, psychologic stress and intracerebral propranolol. Integr Physiol Behav Sci 29:355-61
Skinner, J E; Pratt, C M; Vybiral, T (1993) A reduction in the correlation dimension of heartbeat intervals precedes imminent ventricular fibrillation in human subjects. Am Heart J 125:731-43

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