Current aspects of cognitive neurophysiology of Parkinson disease: an introduction

Parkinson Disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease. With increased longevity and improved health care, our society is experiencing an unprecedented challenge posed by neurodegenerative disorders. Alzheimer's disease alone is now the third most expensive disease to treat in the U.S., costing close to $100 billion annually. While treatment of the motor manifestations of PD has advanced much, the treatment of its non-motor features, in particular mental dysfunction remain as unresolved problems in PD. Electrophysiological and imaging studies in this issue are providing new information on the roles of the frontal cortex, pedunculopontine nucleus, dopaminergic mesolimbic system and thalamocortical circuits on cognitive and mental dysfunction in PD.