May 20, 2007


Just as a phosphorescent object is best seen in absence of light, the functions of some organs of our body is best revealed when they are removed or malfunctioning. The best known example is perhaps that of Best and Banting's discovery of insulin on their pancreatectomized dogs, (i.e. dogs whose pancreas was removed). Likewise, cerebellar diseases reveal many of its functions/things, the healthy cerebellum apparently didn't.

In about 1% of alcoholics, there is degeneration of the cerebellum, particularly the vermis, a midline cerebellar structure. The person develops nystagmus (jerky movement of eyeballs), an increasingly unsteady gait; superimposed on an unsteady stance. Vitamins and other medications are of little use. However, this instance clearly signifies the cerebellum's role in maintaining posture and movement.

Other posture and movement abnormalities like intention tremor occurs. Distance measuring and rapidly alternating tasks are also hampered. The cerebellum analyzes the 'error voltage' and stores the best response in its memory: all this data are destroyed in cerebellar disease. Thus when a patient reaches out for the tip of his nose, with his index finger, for example, the finger overshoots and gets past the target. This occurs as the relevant database as to how much force to be applied and for how long, before the brake (activation of antagonist muscles) is applied; are destroyed. This is known as past pointing. Now the patient understands it and tries to correct the error. He past points again, and this process goes on. Intention tremor results.

Related article: Cerebellum, electronically speaking
The Cerebellum- Part 2