Quantitative Behavioral Assessment Methods for the Analysis of Graft-Induced Motor and Cognitive Function in the MPTP- Treated Parkinsonian Monkey

Although the MPTP-treated monkey is the best available model of Parkinson’s disease in terms of neuropathophysiology, the usefulness of the model for the functional analysis of neural grafts requires methods that can determine the severity and persistence of the symptoms. Wide variation in response to MPTP and reports of "spontaneous" recovery may warrant a variety of assessment methods to determine the severity of parkinsonism and this requires large numbers of subjects and groups. It is critical that the severity of the MPTP deficit be known in order to compare MPTP-treated subjects with fetal substantia nigra (SN) implanted into the caudate nucleus (CN) with similarly affected subjects given sham surgery, "inappropriate" surgery (cerebellar tissue into the CN or SN tissue into the cortex), or no surgery. If subjects in these groups are not compared by severity it will not be possible to differentiate between graftinduced and spontaneously-induced improvements. We have aimed to establish a variety of behavioral assessment methods that can identify the severity of the MPTP-induced behavioral deficit. With these methods we can more accurately study the restorative effects of grafts in MPTP-treated monkeys with which the biochemical and morphological effects can be compared. We have used the following methodologies in our studies: 1) spontaneous behavioral ratings; 2) cognitive and subtle motor skill task performance, and 3) eye-blink rate measure