Pyramidal tract and corticostriatal neuron recordings in MPTP-treated macaque performing visuomotor tasks

Longitudinal single-unit electrophysiology recordings from the primary motor cortex of two rhesus macaque monkeys (Macaca mulatta), acquired both before and after induction of parkinsonism by systemic MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) intoxication. Recordings span two subjects (Leu, recorded in 1993; Venus, recorded between 1999 and 2000), covering both the healthy baseline state and the parkinsonian state, and support analyses of how dopaminergic lesion alters cortical motor encoding. Within primary motor cortex, two classes of cortical projection neurons are distinguished by antidromic activation from chronically implanted stimulating electrodes: pyramidal tract neurons (identified by stimulation from the cerebral peduncle) and corticostriatal neurons (identified by stimulation from the posterior putamen). Each recording site is verified as primary motor cortex by intracortical microstimulation at thresholds below 30 microamperes. The behavioral paradigm is a visuomotor step-tracking task in which the monkey produces flexion or extension elbow movements against a torque motor to align a cursor with visual targets, through a structured sequence of center hold, target presentation, movement execution, target hold, and liquid reward. A subset of trials includes unexpected torque perturbations that elicit muscle-stretch reflexes, enabling analyses of sensory feedback in the parkinsonian state. Original analyses on subsets of these data appear in three peer-reviewed papers (Pasquereau and Turner 2011, Cerebral Cortex; Pasquereau and Turner 2013, Frontiers in Systems Neuroscience; Pasquereau, DeLong, and Turner 2016, Brain), linked in the related-resources section.