Home > Conscious > Chapter 1 > 1.1. Brainstem and Cerebellum


The brainstem is located at the base of the brain, connecting the spinal cord with the rest of the brain. It controls heartbeat, blood pressure and breathing that are essential for survival. The brainstem also relays information between the brain and the spinal cord, which then sends out messages to the muscles, skin, and other organs.


Figure 1-2. Structures of the brainstem. [Source: Wikipedia]

The brainstem consists of three parts: midbrain (mesencephalon), pons and medulla (Figure 1-2). The midbrain include three areas relevant to this book:

  • Reticular formation is involved in the arousal and conscious systems. Impairment in this structure may result in coma.
  • Substantia nigra pars compacta plays important roles in motor functions. The Parkinson's disease is caused by damage in this area.
  • Ventral tegmental area may convert the feeling of "liking" into the action of "wanting" for alcohol, addictive drugs, money and sex.

The cerebellum is located above the brainstem, with weight about 10% of the brain. It plays important roles in balance and coordination. The cerebellum has two hemispheres, receiving information sent from the eyes, ears, muscle and joint about the body's position and movement. After the information is processed, the cerebellum sends instructions to the body through spinal cord and the rest of the brain. The cerebellum is also involved in learning and memory about movement, such as playing piano or tennis.