Meshul received his PhD in 1982 in the department of anatomy and cell biology at the University of Illinois Medical Center, with an emphasis in neuroanatomy and electron microscopy. He completed his 2-year postdoctoral fellowship in the Department of Pharmacology at the University of Maryland Medical Center, with an emphasis in neurotoxins and electron microscopy. In 1984, he began work at the Portland Veterans Administration Medical Center and Oregon Health & Science University in Portland, Oregon, with an emphasis in the effects of neuroleptic drugs on the basal ganglia, utilizing both electron microscopy and pharmacology. In the late 1990’s, he switched his focus to Parkinson’s disease in pre-clinical models. Meshul has developed a new progressive pre-clinical model of the disease, whereby increasing the weekly dose of this toxin leads to a gradual loss of dopamine neurons, which correlates with deficits in motor function.