The human brain is an incredible organ. It controls memory and learning, the senses (hearing, sight, smell, taste and touch) and emotions. It also controls other parts of the body, including muscles, organs, and blood vessels.
The brain can be a really complex structure. It accommodates billions of nerve cells – called neurons – that must communicate and work together for the body to operate normally. The neurons communicate via electrical signals. Special chemicals called neurotransmitters help transmit these electrical messages from neuron to neuron.
Information is fed into the brain via the senses. What is heard, felt, tasted, seen or smelled is recorded by receptors in or on the body and transmitted to the brain via sensory neurons. The brain decides what to do with the knowledge from the senses and tells the body methods to respond by sending messages through motor neurons. For example, when an individual puts their hand near something hot, the sense of touch tells the brain concerning the heat, and the brain sends a message to the arm muscles to maneuver the hand away. Another form of neuron – called interneurons – connect various neurons within the brain and spinal cord, which together form the central nervous system.
Just as there are several types of neurons, there are also several types of chemical neurotransmitters. Researchers who study mental illness consider that abnormalities within the functioning of certain brain circuits contribute to the event of many mental illnesses. Connections between nerve cells along specific pathways or circuits within the brain may cause problems processing information within the brain and result in abnormal mood, pondering, perception, or behavior.
Researchers also consider that changes in the scale or shape of various parts of the brain could also be accountable for the event of some mental illnesses.
