The nervous system is integrated with the normal function of every one of the horse's organs. In turn proper function of the nervous system depends on the proper functioning of each of the body's organs. Diseases of the nervous system are usually first exhibited as a change in the horse's alertness, behavior, gait, and/or ability to sense the world around them. The horse may just have one of these changes or a combination of different symptoms. Primary neurologic disease in horses is a common problem and can be a diagnostic challenge because:

• The central nervous system is not easily observed and directly examined.
• Large number of similar diseases effecting the nervous system.
• No matter what the cause of the disease, the symptoms seen depend on the location of the disease. Different diseases will have similar symptoms if they effect the same location of the nervous system.

On the helpful side is that certain diseases tend to have a specific history, a predilection for localization to certain areas of the nervous system, and to have a certain signalment. Signalment is the circumstances, history, sex, age, breed, etc... under which the disease occurs. Combining the history, signalment, and localization of the lesions often provides a working diagnosis. Localizing neurological diseases to certain areas requires a understanding of the functional regions of the nervous system.

This article will help equestrians accurately label the symptoms which is the first step to localizing the disease. Once the symptoms are accurately labeled links are provided to articles that will further help them differentiate the diseases that effect that area and ways to differentiate them. Once a list of differential diagnoses is generated an appropriate diagnostic and therapeutic regime can be planned.

The nervous system can be grouped into functional regions that correspond with anatomical structures. Understanding how the symptoms your horse has and their relation to where in the nervous system they are influenced is the first step to localizing the disease:

• The Cerebrum (Brain): Thinking, alertness, voluntary movement
• The Cerebellum (Brain): Fine control of muscular activity
• The Brainstem: Cranial nerves, fine control of muscular activity, maintenance of conscienous
• The Cranial Nerves: A conduit between the brain and the senses of the head (sight, hearing, taste, touch, and balance) and motor control of the muscles of the face, chewing, and swallowing. Also motor control to the skeletal muscles to maintain balance.
• The Spinal Cord: A wiring system for communication of the
  • brain with the peripheral nerves (lower motor neurons and sensation)
  • peripheral nerves with the brain and spine
  • peripheral nerves with other peripheral nerves (commonly relex actions)
• Peripheral nerves: A conduit for communication of the spinal cord with the muscles and the sense of touch.

Notice there is a lot of overlapping functions that require further understanding to help with localization. Usually the other symptoms present or the nature of the specific symptom help with this.