ABSTRACT
Major endogenous bodily rhythms include circadian, infradian, circannual, and ultradian; these are influenced by exogenous zeitgebers. Circadian rhythms, which include sleep-wake cycle, have been investigated by volunteers spending time in deep underground caves (Siffre) or in a bunker (Aschoff) in the absence of sunlight or any other zeitgebers. The average duration of the human internal circadian clock is 24 hours, 15 minutes; this is reset each day to the light/dark cycle of the external world and is thought to be the suprachiasmatic nucleus (SCN) in the medial hypothalamus. Mind time is influenced by a variety of factors (including age, the situation, and the state of our brains). Using the ‘wagon-wheel illusion’, researchers have claimed some support for the view that perception of the world involves a series of distinct snapshots (like film frames). However, we experience the world as continuous, as explained by Pöppel's building blocks of consciousness hypothesis; this is consistent with the dopamine loop account. This, in turn, relates to our sense of ‘now’, James's ‘specious present’, or Edelman's ‘remembered present’. Pöppel's ‘subjective present’ is related to the three-second window account of consciousness. Husserl's internal time-consciousness is an account of how earlier and later one's moments of consciousness are interconnected.
