Fox squirrel (Sciurus niger): The fox squirrel is the largest tree squirrel in Illinois, weighing one and three-quarters to two pounds with a length of 19 Â½ to 22 inches. The fur is a mix of rusty-yellow with black with an overall reddish cast. The fur on the ears, belly, and edge of the tail is lighter.
Audiologists are able to measure the speed and intensity of these pulses to determine if there is hearing loss or a lesion that is upsetting the flow of the sound information through the brainstem. This measurement is called a brainstem auditory evoked response (BAER).
In the human brain the brainstem includes the midbrain, the pons, and the medulla oblongata. Sometimes the diencephalon, the caudal part of the forebrain, is included. The brainstem provides the main motor and sensory innervation to the face and neck via the cranial nerves. Of the twelve pairs of cranial nerves, ten pairs come from the brainstem. Though small, this is an extremely important part of the brain as the nerve connections of the motor and sensory systems from the main part of the brain to the rest of the body pass through the brainstem.