Parkinsonism: evolving pathophysiologic concepts

The link between the hallmark pathology in Parkinson's disease, i.e., dopamine loss in the basal ganglia, and the behavioral signs of parkinsonism, remains mysterious. This presentation will review our knowledge of system-level changes in brain activity in parkinsonism. The most commonly discussed models of the changes in brain activity that lead to parkinsonism were developed twenty years ago, and were strongly based on anatomical considerations and changes in the firing rates of basal ganglia neurons in dopamine-depleted animals. The most important change noted was an increase in the activity of neurons in the…