THE EFFECT OF EXPERIMENTAL INSOMNIA ON THE RATE OF POTENTIAL CHANGES IN THE BRAIN

Abstract

Analyzing the rate of the potential changes of the brain on the basis of % time frequency distribution revealed that increasing periods of insomnia (up to 100 hrs.) resulted in an increase in the rate of the electrical activity in the brain. This effect was first evident after 50 hrs. of sleeplessness and reached a maximum at about 75 hrs. Changes in the state of attention or alertness as produced by working a mental multiplication problem during the control days also increased the rate of the potential pattern of the brain. Superimposing such an additional mental effort (multiplication problem) during exptl. insomnia resulted in irregular changes, indicating that the capacity of the fatigued brain to still further increase its rate of electrical activity in response to such stimulus is reduced. Since the changes produced by mental activity and by sleeplessness are in the same direction, it is interpreted to indicate that mental attention or "effort" required either for working a problem or staying awake during exptl. insomnia produces an increase in the rate of the electrical activity of the brain.