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).
Alternative Title: brain stem Brainstem, area at the base of the brain that lies between the deep structures of the cerebral hemispheres and the cervical spinal cord. The brainstem is divided into three sections in humans: the midbrain (mesencephalon), the pons (metencephalon), and the medulla oblongata (myelencephalon). The brainstem is a sort of automatic control centre for several important involuntary actions of the body, such as heartbeat, breathing, blood pressure, and many reflexes.