Affiliations: Department of Psychology, Texas Christian University,
Fort Worth, Texas, USA
Note: [] Corresponding author: Stefanie L. Byler, Department of
Psychology, Texas Christian University, Box 298920, Fort Worth, Texas, 76129,
USA. Tel.: +1 817 257 7410; Fax: +1 817 257 7468; E-mail: s.l.byler@tcu.edu
Abstract: Purpose: To better understand the behavioral effects of pallidotomy
as a treatment for a range of movement disorders, including Parkinson's
disease, chorea, and ballismus. In some cases, pallidotomy increases movement
whereas in others it decreases unwanted motor behavior. Method: The present
study investigated the effects of unilateral pallidotomy in rats with an
otherwise healthy nervous system. Pallidotomized and sham lesion rats were
evaluated on a battery of tests that measure sensorimotor behavior. Results:
Compared to sham lesion controls, pallidotomized rats showed motor deficits
(forelimb placing; bracing) and excesses (locomotor behavior) as well as
sensorimotor asymmetries (ipsilateral adhesive patch bias; increased
contralateral foot faults). Conclusion: Motor deficits observed after
pallidotomy were similar to those reported in previous research from this and
other laboratories following damage to the nigrostriatal pathway or
sensorimotor cortex. Motor excesses after pallidotomy are consistent with
current theories of globus pallidus function. Taken together, these data
suggest hypokinetic effects of pallidotomy may be related to fibers of passage
(i.e. internal capsule), while hyperkinetic effects may be related to damage of
pallidal cell bodies. These data may have important clinical implications
because they suggest that regardless of the state of existing pathology,
pallidotomy may create unwanted behavioral side effects.
Keywords: Pallidotomy, motor deficits, motor excesses, Parkinson's, chorea, entopeduncular nucleus, rats
