Parkinson's disease After discovering the function of the<unk> , it has become apparent to neurologists that the<unk>  and other parts of the basal ganglia play an important role in Parkinson's disease and other diseases that involve the degeneration of neurons. Parkinson's disease is the slow and steady loss of dopaminergic neurons in substantia nigra pars compacta. In Parkinson's disease the<unk>  plays a key role because its inputs and outputs are interconnected to the substantia nigra and the globus pallidus. In Parkinson's disease the activity in direct pathways to interior globus pallidus decreases and activity in indirect pathways to external globus pallidus increases. It has also been noted that Parkinson's patients have a difficult time with motor planning. Other diseases and disorders The following diseases and disorders are linked with the<unk> : * Cognitive decline in Alzheimer's disease * Huntington's disease * Wilson's disease * Dementia with Lewy bodies * Corticobasal degeneration * Tourette syndrome * Schizophrenia * Depression * Attention deficit hyperactivity disorder * Chorea * Obsessive-Compulsive Disorder * Kernicterus * Other anxiety disorders
Putamen
Inferior colliculus
Arcuate nucleus 
Periventricular nucleus
Barrel cortex
Medulla
Medulla 
Piriform cortex