Neurotransmitters are the chemical substances that act to communicate across synaptic cleft. These neurotransmitters helps in transferring of information from one neuron to the other neuron.
The responses perceived by the sensory receptors are transmitted the brain by means of chemical messengers. Depending upon the chemical messengers released, the brain integrates the data and regulates the behaviour.
The concept of chemical imbalance in the brain is associated with behavioural disorders such as Parkinson’s disease (PD). PD is associated with an imbalance in dopaminergic and cholinergic neurons. However, establishing a clear relationship between the other neurotransmitters and behaviour has proven difficult.