The Biology of Dreaming and the Informational Underload (Sensory Deprivation) Theory of Psychosis*

Abstract

This paper is concerned with the interpretation of the informational underload hypothesis of mental illness into the D-state. Although the uniformity of sensory deprivation experiments has not yet been proven, it is nevertheless assumed that this uniformity exists and that sensory deprivation in the strict sense, perceptual isolation and sensory monotony all lead to a state of informational underload of the central nervous system. A minimum amount of information is needed by the organism and between organism and environment. The consequences of informational underload are assumed to be disequilibria within the organism itself, between the organism and its environment and also a disintegration of previously integrated central nervous system functioning. The informational underload hypothesis, developed from sensory deprivation experiments, may also be interpreted into a wide variety of mental decompensations by assuming that pathological interference with the gating mechanisms of the nervous system takes place. The D-state is also seen as an example of informational underload in that there is a considerable excitation within the brain with blocking of input at the periphery. The mechanism of disintegration of holistic nervous functioning under conditions of informational underload is discussed. It is assumed that the integrated cueing function, which unifies the entire nervous system in holistic operations, and the executive of which is thought to be the reticular formation, responds to incoming information. This will fail if insufficient amounts of information enter the nervous system and lead to semi-autonomous functioning of its constituent parts. The central cueing function itself is thought to be discontinuous and operating at a maximum rate of about every 50 milliseconds. If the interpretation of this model into the D-state is correct, then this state is characterized by disintegration of holistic functioning. Support for this is found in some findings in the field of epilepsy — the lack of complete correlation between the physiological changes of the D-state and dream content and the irregularities in many autonomic parameters. The possible biological significance of the D-state is discussed. The ‘deprivational' line of argumentation is rejected. It is pointed out that D-deprivation experiments may well be contaminated by a built-in conditioning procedure which does not take place during awakenings from the S-state. During the ontogenetic development a differentiation between a state of low activity of arousal of the nervous system, the A- state, and one of high activity or arousal, the A+ state, is necessary. There is also a gradual shift from as yet unintegrated functioning to integrated functioning of a holistic nature by cueing on the basis of incoming information during both states. Primitive sleep and primitive waking are both originally unintegrated states, later in the development becoming integrated. It is assumed that the basic metabolic equilibrium is not between behavioural sleep and waking, but between the A+ state, including waking and dreaming, and the A- state, or dreamless S. Thus the D-state is not a particular way of being asleep, but a particular way of being awake. The total amount of A+ time increases from 16 hours at birth to 18 hours in adulthood, which is in line with changing metabolic requirements for A- or S. In order to explain the change in distribution between D and W within A+, it is important to realise that W and D at birth are both unintegrated states and probably represent an oscillation between entero- and distance perception. A rest-and-activity cycle of 60 minutes at birth is assumed and thought to lengthen to 90 minutes with maturation. As meaning begins to develop in the W-state, parallel with the development of attention or focal awareness and of central integration, the W-state becomes more and more self-perpetuating, overriding the rest-and-activity cycle. Under conditions of prolonged arousal or A+, a metabolic need for A- or S develops. With this physiological pressure a reflex develops consisting of an input shutdown at the peripheral level on moments during behavioural sleep when the 90-minute rest-activity cycle tends to lift the organism from A- to A+. Thus the D-state is brought about and because of its lack of central integration, this variety of the A+ state is not self-perpetuating and a return to S is reassured until the metabolic need for S is fulfilled. Therefore D is there to guarantee a suffirent amount of S. The D-reflex is dependent on the development of the attention function. It is assumed that such a mechanism is only possible in the phylogenetic development if the regulation of informational input has become established.