NEUR 3200 Lecture Notes - Lecture 2: Substantia Nigra, Pars Compacta, Subthalamic Nucleus
31 Oct 2017
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Document Summary
Parkinson"s disease (pd) is a chronic, progressive, neurodegenerative disorder. Although there are genetic and environmental risk factors, a definitive cause has not yet been discovered. Risk of pd increases with age, but an early-onset variant occurs before age 40. The most visible outward sign of pd is a resting tremor that occur when limbs are relaxed, and disappears with intentional movement. There is both difficulty in initiating movement (akinesia) and slowing of movement in general (bradykinesia). Less movement of facial muscles reduces the range of facial expression possible. Bradykinesia also results in small handwriting, decreased speaking volume, and monotonous speech. Rigidity in the joints is another common symptom leading to a shuffling gait: degeneration of d1 and d2-like receptors in the basal ganglia (responsible for motor fxn) Except for the resting tremor, motor symptoms are explained by loss of dopaminergic cells in the substantia nigra.
