This lecture explains the major neurotransmitters involved in emotional and behavioral functioning, with emphasis on serotonin, dopamine, norepinephrine, GABA, and glutamate. It reviews their roles in mood, anxiety, sleep, motivation, attention, reward, and cognition, and shows how imbalance in these systems may relate to common psychiatric symptoms. The lecture also introduces key concepts such as excitatory versus inhibitory neurotransmission, serotonin synthesis and distribution, and the relationship between neurotransmitters and brain circuits involved in emotion. In addition, it provides a simple explanation of how SSRIs and SNRIs work at the synaptic level and how these treatments may influence emotional regulation and neural recovery. Overall, it offers a practical foundation for understanding core principles of biological psychiatry.

Key Topics:

• Functions of serotonin, dopamine, norepinephrine, GABA, and glutamate
• Neurotransmitter roles in mood, anxiety, sleep, reward, and attention
• Balance between excitatory and inhibitory brain activity
• Serotonin synthesis, pathways, and relevance to brain and gut function
• Basic mechanism of action of SSRIs and SNRIs
• Link between neurotransmitter imbalance and common psychiatric symptoms