CHARACTERISTICS AND SOMATOTOPIC ORGANIZATION OF KINESTHETIC CELLS IN THE GLOBUS-PALLIDUS OF PATIENTS WITH PARKINSONS-DISEASE

Information is limited on the characteristics and topographic localiza tion of pallidal kinesthetic cells in patients with Parkinson's diseas e. The authors analyzed the data from 298 neurons recorded in 38 patie nts with Parkinson's disease who underwent pallidotomy via microrecord ing techniques. Sixty-five neurons (22%) responded to passive movement of contralateral limbs. Of 17 kinesthetic cells that were tested in s ix patients, seven (41%) responded to ipsilateral limb movement as wel l. Nineteen cells (6%) fired synchronously with tremor. More kinesthet ic cells were activated (63%) than inhibited (28%) by movement of sing le (68%) rather than multiple (32%) joints, and proximal (75%) rather than distal (25%) joints. The lateral globus pallidus externus (GPe) a nd medial globus pallidus internus (GPi) pallidal segments contained s imilar proportions of kinesthetic cells, activated or inhibited cells, arm- or leg-activated cells, and cells responding to single or multip le joints. Significantly more kinesthetic cells that responded to dist al joints were recorded in GPi compared to GPe segments (p = 0.01). Ar m and leg cells had similar characteristics pertaining to activation v ersus inhibition and responses to single, multiple, proximal, or dista l joint movements. Arm and leg cells were somatotopically organized in GPI. Arm cells were clustered at the rostral and caudal segments of G Pi and leg cells were clustered centrally. In GPe, leg cells were clus tered at the caudal border. No somatotopic organization was identified for activated or inhibited cells; cells that responded to single, mul tiple, proximal, or distal joints; tremor-synchronous cells; or cells responding to specific joints within somatotopic arm or leg cells. It is concluded that kinesthetic cells provide a roadmap that localizes l imb cells during pallidotomy. More studies are needed to identify the clinical significance of the different characteristics of kinesthetic cells.