Reticular Activating System.

... RETICULAR ACTIVATING SYSTEM R.A.S. is very susceptible to damage. Is suppressed by chemicals during sleep. Acts as a filter of sensory messages passing through to the cerebral cortex. Function of R.A.S. Cut/lesion above R.A.S. This would cause a permanent coma. Cut/lesion below R.A.S. This would cause paralysis from the point below the lesion. Cut/lesion through RAS Damage to this will keep a person awake. Diagram including location of R.A S., pons, & Raphe nuclei. Chemical analysis of the RAPHE found SEROTONIN. (This was investigated to find a cur for coma victims). Serotonin is a neurotransmitter. This acts an inhibitor on the R.A.S. This leads to a gradual decrease in arousal. This is the mechanism for falling asleep. R.A.S. is also inhibited by nor-adrenalin, released by the pons. This closes the RAS system down further. Noradrenalin acts as and exitory agent on motor/sensory pathways and could cause REM/dreaming sleep. Havever found a system which reinhibits the motor pathwau after it has been

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