Reticular activating systemConsciousness & sleep

Dr. Sadaf Mumtaz15/03/12

Consciousness

• ‘Subjective awareness of external world and self, including awareness of the private inner world of one’s own mind’

Excitatory activating system of brain

Areas of the cerebral cortex that connect with specific portions of the thalamus

Collection of neurons in the brain stem secreting different transmitters

SleepTypes of Sleep

Characteristics Slow wave sleep REM sleep

EEG Displays slow waves Similar to EEG of alert awake person

Motor activity Considerable muscle tone Abrupt inhibition of muscle tone

Heart rate, respiratory rate and blood pressure

Minor reductions Irregular

Dreaming Rare (mental activity is extension of waking time thoughts)

Common

Arousal Sleeper easily awakened Sleeper hard to arouse but apt to wake up spontaneously

Percentage of sleeping time

80% 20%

Other important characteristics

Has four stages Rapid eye movement

Serotinin

Sleep inhibition centers

• Nucleus of tractus solitarius• Rostral part of hypothalamus • Diffuse nuclei of thalamus Diencephalon

Possible cause of REM sleep

Brain waves

Behavioural patterns during sleep

Synchronization and Desynchronization of brain waves

Epilepsy

• Depression• Manic-depressive psychosis• Schizophrenia• Alzheimer’s disease

Thanks