A 34-year-old woman with a long-standing history of seizure disorder presents to her neurologist with difficulty walking and coordination. She states she has had an acute change in gait, unclear speech, blurring of vision, tremor with movement, and loss of hand coordination. She has never had symptoms like this before. She denies headache and vertigo or any other complaints. On examination, she has an unstable gait and poor hand-eye coordination. She is noted to have nystagmus along with a fine tremor of the hand when she is moving it. A urine drug screen is negative. She has a computed tomography (CT) scan and lumbar puncture, which are both normal. Phenytoin levels are slightly elevated. She is diagnosed with cerebellar ataxia.

• Describe the part of the cerebellum which is responsible for planning and initiation of movement?

• Discuss the output of the cerebellar cortex and state whether its excitatory, inhibitory, or both?

• Describe the life cycle of is the neurotransmitter for Purkinje cells?