Intravenous N-acetylcysteine for the Treatment of Gaucher's Disease and Parkinson's Disease

The investigators are interested in determining if the investigators are able to detect changes in brain chemistry using Magnetic Resonance Spectroscopy (MRS) in individuals with Parkinson's disease (PD), those with Gaucher's disease (GD), and those without neurological disorders (healthy controls) when they are given the antioxidant N-acetylcysteine (NAC). This study will combine information from a medical history, a physical examination and disease rating scales with results obtained using MRS brain scans and pharmacokinetic studies from blood samples. This research will require 1 visit that will require about 4 to 5 hours of time. During this study, participants will provide their medical history, be examined and undergo a rating scale for about one hour; the brain scan and pharmacokinetic studies will require 1.5-2 hours of time; in total the study will take about 4-5 hours.