Neurotransmitters are small molecules that are released into the synaptic cleft, where they bind into specific receptors that can either cause the opening of ion channels and depolarize the membrane potential or cause the closing of ion channels and hyperpolarize the membrane potential.
This process is critical for many functions in the body, including sensory perception, motor control, learning and memory, and emotional regulation. Dysfunctions in neuronal signalling can lead to a wide range of important neurological and psychiatric disorders.