Which neurotransmitter is primarily involved in motor movement and alertness?

The neurotransmitter primarily involved in motor movement and alertness is acetylcholine. This neurotransmitter plays a critical role in transmitting signals from motor neurons to muscles, enabling movement. It is also involved in various functions in the brain, particularly in enhancing alertness and attention.

While serotonin is mainly associated with mood regulation, GABA serves as the primary inhibitory neurotransmitter in the brain, helping to calm neural activity. Dopamine, though not the correct answer here, is also significant for motor control and is closely related to reward and motivational aspects but does not primarily serve the same role in broad alertness and direct motor function as acetylcholine does.