Limbic autonomic arousal: its physiological classification and review of the literature.

The object of this article is to present a novel physiological classification of Limbic-Autonomic (LA) arousal on the basis of human physiological data, specifically the oro-nasal breathing patterns in man. It is proposed that the multidimensional LA arousal can be classified into five grades: Grade I: Non-nasal (NN) or oral breathing with bilateral nasal congestion, and nonactive behavior, Grade II: Left Nasal (LN) breathing and quiet behavior, Grade III: Right Nasal (RN) breathing and active behavior, Grade IV: Bilateral Nasal (BN) breathing and very active behavior, and Grade V: Oral and Bilateral Nasal (ON) breathing with maximal behavioral activation. The data from polygraphic electroencephalographic recordings from five healthy volunteers, before, during and after exercise are presented in support of this physiological classification of LA arousal. On the basis of Limbic-Autonomic asymmetry a novel concept of "Visceral Dominance" is also proposed.