Which neurotransmitter is linked to mood regulation and learning, besides its role as a hormone?

The neurotransmitter that is closely linked to mood regulation and learning, in addition to its role as a hormone, is serotonin. Serotonin plays a critical role in mood stabilization, impacting feelings of well-being and happiness. It is also involved in various cognitive functions, including learning and memory. Low levels of serotonin are associated with conditions such as depression and anxiety, highlighting its importance in both mood regulation and overall mental health.

Other neurotransmitters mentioned, like norepinephrine, dopamine, and glutamate, have different primary roles. Norepinephrine is primarily associated with arousal and alertness, while dopamine is involved in reward processing and motivation. Glutamate serves as the main excitatory neurotransmitter in the brain and is essential for synaptic plasticity, crucial for learning, but does not significantly influence mood regulation in the same way that serotonin does. Thus, serotonin is the best choice given its dual role in mood and cognitive processes.