Mental conditions reflected by the chaos of pulsation in capillary vessels

The presence of deterministic chaos has been clarified experimentally in th e time series of pulsation of capillary vessels [Tsuda et al., 1992]. In th is paper, first we reconfirmed the nonlinearity of the time series of pulsa tion of capillary vessels with surrogate data testing. Second, we investiga ted the characteristics of chaos of capillary data on normal subjects in di fferent states of the autonomic nervous system and on psychiatric patients. As a result, the chaotic fluctuations decreased for the state of sympathet ic dominance of normal subjects. On the contrary, the chaotic fluctuations increased for the state of parasympathetic predominance of normal subjects. We also found that the chaotic fluctuations decreased in the symptomatic p hase of psychiatric patients. Interpretation of this fact is as follows. Psychiatric patients in symptomatic phase are in a condition of poor flexib ility of emotion and motivated behavior in the limbic system. This conditio n affects the regulation of the autonomic nervous system in the hypothalamu s. So it is easy to fall into the imbalance of the autonomic nervous system even with slight stress. Furthermore, in the attractor of capillary chaos we found two parts that showed the role of origin of stimulation of the sym pathetic nervous system and that of stimulation of the parasympathetic nerv ous system, respectively. The geometrical change of topology was caused by the interplay of two parts. From our study we concluded that chaos of pulsa tion in capillary vessels reflected mental conditions through the autonomic nervous system.