A police officer has just stopped Bill on suspicion of driving while intoxicated. The officer asks Bill to walk the yellow line on the road and then asks him to place the tip of his index finger on the tip of his nose. Which part of the brain is being tested by these activities?
When a police officer gives someone a sobriety test they are testing the cerebellum which is responsible for our balance, coordination and muscle movement. The cerebellum is located in the "posterior fossa of the skull," which is the lower back, and is divided into two hemispheres, a right and a left hemisphere, each of which is divided into lobes. When under the influence of alcohol nerve impulses are interrupted and the message from the brain cannot make it through the central nervous system to the muscles of the body which results in poor balance and limited fine motor skills, which would result in poor coordination if someone were under the influence of alcohol.