Although the neural science behind alertness, wakefulness, and arousal are not fully known, the reticular formation is known to play a role in these. The ascending reticular activating system is a postulated group of neural connections that receives sensory input and projects to the cerebral cortex through the midbrain and thalamus from the retucular formation. Since this system is thought to modulate wakefulness and sleep, interference with it, such as injury, illness, or metabolic disturbances, could alter the<unk>  of consciousness. Normally, stupor and coma are produced by interference with the brain stem, such as can be caused by a lesion or indirect effects, such as brain herniation. Mass lesions in the brain stem normally cause coma due to their effects on the reticular formation. Mass lesions that occur above the tentorium cerebelli normally do not significantly alter the<unk>  of consciousness unless they are very large or affect both cerebral hemispheres.
Altered level of consciousness
Altered state of consciousness
Clouding of consciousness
Psychomotor agitation
Snatiation
Catalepsy
Mental distress
Transient loss of consciousness