Final answer:
The reticular formation is a diffuse region of gray matter located throughout the brain stem that regulates various physiological functions.
Step-by-step explanation:
The reticular formation is a diffuse region of gray matter located throughout the brain stem that regulates various physiological functions. It is primarily responsible for regulating the sleep/wake cycle, arousal, alertness, and motor activity. The reticular formation extends from the midbrain into the forebrain and the hindbrain.