If the disturbance causes enough arousal, the person may wake up. At that point the person may be able to discern what kind of sensory disturbance caused the arousal. This is because the information has been transmitted to the thalamus where more specific analysis takes place. As mentioned previously, animal research has shown that if the reticular formation is deactivated, the animal becomes somnolent. Thus, the reticular formation plays an important role in keeping the organism awake and alert as well as being important in the sleep process.
All animals have what is known as circadian rhythms .
Thus, circadian rhythms refer to the cycles of approximately 24 hours duration. The body has a sort of internal clock which influences the internal state depending on the time of day. The circadian rhythms are synchronized by this internal clock. An example of a circadian rhythm is body temperature. Body temperature typically begins to rise as morning nears, peaks during the day, and begins to drop around sleeping time.