Patient description: A 57-year old farmer was diagnosed with Parkinson's disease a year ago. He experiences slowness of movement and tremors. His past medical history is significant for hypertension and hypercholesterolemia. He lives with his wife. They have three children. He used to be active with planting and taking care of their farm animals before his diagnosis. The patient complains of shaking and slow movement. He had difficulty entering through a door, as he was frozen and needed guidance to step in. His handwriting is getting smaller. He is on Levodopa and Trihexyphenidyl. He stated his medications help with shaking and slow movement. But he still has difficulty initiating movements, stiffness and slowness in general. He is an alert and cooperative man who doesn't have any signs of dementia. He doesn't smoke or use any illicit drugs.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Healthy Healthy volunteers will be over 18, and willing to participate, and able to give informed consent. The stroke patients will have a clinically and radiologically documented stroke in the sub-acute (2 weeks to 6 months to after onset) or the chronic state (more than 6 months after onset), having a lesion in sub-cortical regions including the basal ganglia, thalamus, internal capsule, or a combination of these structures, or cerebellum unilaterally. These lesions can extend to the surrounding areas, however not including the cortical areas. Patients will be over 18 years of age. PLS/ALS Patients must fulfill the diagnostic proposed by Pringle (1992) for PLS and have been diagnosed with PLS for at least 3 years. onset of spasticity alone in adulthood, slow progressive course, no family history, no lower motor neuron signs, and of known causes of spasticity. ALS patients should have probable or definite ALS by El Escorial criteria. Patients must have evidence of upper and lower motor neuron signs in two or more defined regions: cranial, arms, legs, or torso. Only the PLS/ALS patients who have recently participated in the study under protocol 06-N-0174 will be included. Some subjects will be studied as inpatients  Subjects who are unable to perform simple voluntary movement with both hands. Subjects who have any neurological or psychiatric conditions. Subjects who have any implanted metal in or on their bodies that cannot be removed prior to the MRI and MEG scans. We are investigating a particular EEG pattern associated with voluntary movement that we believe may not be present in patients with multiple strokes that involve the cerebral cortex; therefore, we will this population of stroke patients. We will, however, patients with multiple strokes if the cerebral cortex was not involved because we hypothesize that the EEG pattern that we are looking for will be preserved in patients with sub-cortical stroke lesions. A. Patients with MRI findings consistent with brain tumors, trauma or AVMs will be excluded. B. Patients with multiple stroke lesions that involve the cerebral cortex will be excluded. C. Subjects with a pre-stroke history of schizophrenia or bipolar disorders will be excluded. D. Subjects with cancer will be excluded. E. Patients not capable of giving an informed consent will be excluded. PLS/ALS PLS/ALS patients with a history or evidence of a coexisting or other neurological disorder, such as stroke, epilepsy, Parkinson's disease, polio, ataxia or neuropathy, or a history of traumatic brain injury, skull defects or neurosurgery will be excluded. PLS/ALS patients will have neuropsychological tests of frontal cortex function under protocol 06-N-0174. Patients with scores below 133 (out of 144) on the Mattis dementia rating scale will be classified as impaired patients who are unable to give their own informed consent and will be excluded. PLS/ALS patients who are unable to travel will be excluded. PLS/ALS patients who are respirator dependent will be excluded