QS Study

States of brain activity

Including Sleep, Wakefulness, Extreme excitement, Exhilaration, Depression, Fear

Sleep Definition

Sleep is a state of unconsciousness from which the person can be aroused by sensory or other stimuli. Most adults need around eight hours of sleep on a regular schedule to function well, although some require less, and others more.

Type: Two type –

  1. Slow wave sleep/Deep sleep/Non-Rim Sleep
  2. Rapid eye movement (REM) sleep/ Paradoxical sleep / Desynchronized sleep.

Sleeping Factors

  • Serotonin
  • Muramylpeptide
  • Nonapeptide (not identified molecularly)

Slow wave sleep – Occurred during the 1st hour the initiation of sleep when brain waves are very large but very Sow.


  • Restful,
  • Dreamless (Dream may occur but cannot be remembered),
  • Decrease peripheral vascular tone,
  • Decrease vegetative function,
  • Blood pressure, respiratory rate, and basal metabolic rate decrease 10-30%.

Rapid eye movement (REM sleep)

Definition – Bouts of REM deep lasting 5-30 minutes usually appear on the average 90 minutes. In extreme sleep bout is short, it may be absent. REM sleep is characterized by irregular breathing and heart rate, and involuntary muscle jerks.


  • Active dreaming and active bodily muscle movement occur.
  • Different to arouse by sensory stimuli.
  • Decreased muscle tone.
  • Heart rate and respiratory rate becomes irregular.
  • Irregular muscle movement occurs with rapid movement of the eye.
  • The brain is highly active and brain metabolism may be increased as much as 20%.

Physiologic Effects of Sleep

  • Restores normal level of brain activity and balance different parts of CNS.
  • Prolonged wakefulness causes progressive malfunction of thought process and abnormal behavior.