ABSTRACT
Brain function represents an integrated outcome from series of complicated tasks such as dynamic adjustment of neuronal metabolism, signal communication, and transmission. Macroscopically, it appears as clusters of neurons firing simultaneously or sequentially at different brain locations. The neuronal signal gets relayed between neurons by releasing neurotransmitters and neuropeptides into synapses to modulate the activity on postsynaptic neurons. The synaptic function can be provoked or interfered with by pharmacological ligands that are specific to a designate neurotransmitter system. Performing a simple sensory, motor, or cognitive task requires complicated neuronal interactions involving evoking and modulating activity from the molecular to the structural level. Dopamine is an important neuromodulator in the brain. The fine balance between its excitatory and inhibitory innervation on the postsynaptic neurons controls the initiation and fine-tuning of many brain functions, such as cognitive, emotional, and a motor controls.
