The right side of your cerebellum controls coordination on the right side of your body; the left side of your cerebellum controls coordination on the left. Diseases that damage the spinal cord and peripheral nerves that connect your cerebellum to your muscles also can cause ataxia. Ataxia causes include: Head trauma. Damage to your brain or spinal cord from a blow to your head, such as might occur in a car accident can cause acute cerebellar ataxia, which comes on suddenly. Stroke. When the blood supply to a part of your brain is interrupted or severely reduced, depriving brain tissue of oxygen and nutrients, brain cells die.
A polar bear has one of the best noses in the entire world and are well known to have an incredible sense of smell. Polar bears have been seen walking in a straight line for 32km (20 miles) to food, with only their nose to guide them. Polar bears have also sniffed out a seal ten football fields away that was hidden under 1m (3') of ice.
If you make it past the claws and teeth you will also find that the fur and skin of a Brown Bear are very thick, up to as much as 8cm thick. A would be predator has to get through all this to even begin to hurt the bear. Bears are also phenomenally strong and their muscle provides yet another layer of protection against attack. They can pick up 220kg seals from the water using their jaws and then carry them ashore to eat. Their jaws, by the way, are powerful enough to bite through 15cm thick trees. Lastly they are athletic beasts.