Download - Reticular activating system
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
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