The brainstem's reticular activating system (RAS) integrates sensory inputs and controls brain activity, regulating alertness and arousal. The suprachiasmatic nucleus (SCN) of the hypothalamus controls the sleep-wake cycle and produces orexin/hypocretin, which promotes awake. Buy Modalert 200 increases alertness via altering dopamine and norepinephrine. Modafinil increases brain neurotransmitters to improve cognition and alertness without stimulant side effects. Understanding these brain pathways is vital for treating narcolepsy and shift work sleep disorder, which need attentiveness.