Interestingly, depigmentation and loss of midbrain dopaminergic neurons within the nigrostriatal pathway is considered to be the hallmark of PD but it is not the first neuropathological presentation. Which of the following neuropathological presentations occurs first in Parkinson's Disease? Lesions to Cranial Nerves 9 and 10 (CN IX and CN X ) Lewy Body formations contributing to cognitive decline Overstimulation of the mesolimbic pathway Hyperpigmentation and overactivation of nigrostriatal pathway.