Glossary

Clusters of neurons that include the caudate nucleus, putamen, globus pallidus and substantia nigra which are located deep in the brain and play an important role in movement. Cell death in the substantia nigra contributes to Parkinsonian signs.

An early indicator that a person may have a disease, such as Parkinson’s. A biomarker, if present, could indicate that the person has a disease before symptoms of that disease appear. There is a search for biomarkers for Parkinson's. Biomarkers could be a chemical, clinical, or imaging finding.

The separating membrane between the blood and the brain; a semi-permeable physical barrier that protects against circulating toxins or pathogens that could cause brain infections while at the same time allowing vital nutrients to reach the brain.