Neurotransmitters are chemical substances that transmit signals between neurons in the brain and throughout the nervous system. They play a crucial role in regulating various functions such as mood, memory, and muscle movement. Research in this area focuses on understanding the roles of different neurotransmitters in the brain, their mechanisms of action, and how they are involved in psychiatric and neurological disorders. Researchers study neurotransmitters through various methods such as neuroimaging, animal models, and pharmacological interventions. This area of research is important for developing new treatments for conditions like depression, anxiety, and Parkinson's disease.