The Phase-Shift Model of Spontaneous Internal Desynchronization in Humans

Abstract

A comprehensive and elegant multiple oscillator theory of human circadian rhythms, which I will call the “traditional” theory, has been developed primarily by Wever (Wever 1979, Aschoff and Wever 1976). The strongest evidence for this theory comes from humans in temporal isolation who show “spontaneous internal desynchronization”. A typical case (Fig, 1, top) shows that the temperature and activity rhythms freeran mutually synchronized during the first section of the experiment (A), but became “desynchronized” during the second section (B). The periodograms for the second section showed two periods in each rhythm, one at 25.1 h which was most prominent in the temperature rhythm, and one at 33.4 h which was most prominent in the activity rhythm. In the traditional theory there are basically two oscillators, one primarily controls the temperature rhythm, and the other primarily controls the activity rhythm. During synchronized freeruns the oscillators are mutually synchronized, but during internal desynchronization they uncouple and freerun with their own natural frequencies.