After about a year, another research team evaluated the levels of NPY immunoreactivity within the fluid encircling the encephalon and the spinal column, termed cerebrospinal fluid (CSF), of 10 individuals suffering from PD, and concluded that the NPY levels were consequentially plummeted, comparably to healthy subjects, reflecting a marked decrease in the liberation of NPY or a marked elevation in the turnover of NPY [164]. Here, NPY is linked to Parkinson disease.