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Basak Gasal Ganglia: Paired subcortical structures that are parts of the extrapyramidal motor system involved in maintaining motor tone and involuntary motor activity. These structures are interconnected with the frontal lobes and when damaged can lead to problems in various domains of executive functions.

Behavior: Any action or response made by an individual. Behavior may be overt or covert. Overt behavior is observable and includes verbal behavior. Covert behavior is not observable; thoughts and feelings are covert behavior. Behavior is also classified as being either respondent or operant.

Bilateral: Occurring on or applying to both sides of the body.

Blunt Impact: The cause of closed head injuries, from a collision between the skull and a blunt object. There is no penetration of the skull, but the skull is often bent inward from the blow.

Brain Death: An irreversible cessation of measurable brain function.

Brain Plasticity: The ability of intact brain cells to take over functions of damaged cells. Plasticity diminishes as a person gets older.

Brain Stem Evoked Response: A response provoked by stimulating the brain stem; may be auditory, visual, and/or somatosensory. A machine is used to test whether the brain stem has received the signals.

Brain Stem: Lower end of brain; the midbrain, pons and medulla; controls all automatic body functions, such as breathing, blood circulation, heartbeat, swallowing and level of consciousness. It also plays a role in governing movement.

Brain Swelling: A significant increase in the size of the brain due to an increase in the amount of blood going there; may occur after severe head injury.

Brain: A large, soft structure of nerve tissue, blood and cerebrospinal fluid contained within the skull. The brain, together with the spinal cord, makes up the central nervous system.