CORTICO-SUBTHALAMIC COMMUNICATION IN EXPERIMENTAL PARKINSONISM

ESCANDE MV; ZOLD CL; RIQUELME LA; MURER MG

Cordoba

Congreso; I reunion Conjunta de Neurociencia; 2009

Sociedad Argentina de Investigación en Neurociencia

The subthalamic nucleus is a key element between basal ganglia circuit that receives cortical afferents through a monosynaptic pathway (hyperdirect pathway) and a multisynaptic pathway involving the striatum and globus pallidus (indirect pathway). In Parkinson’s disease the subthalamic nucleus suffers some changes in its activity that could probably explain some of the clinical manifestation observed in patients. Although it is accepted that these changes imply an abnormal synchronization with cerebral cortex, it is not clear which pathways mediate this abnormal cortico-subthalamic synchronization. As an initial approach for the study of the connectivity between cerebral cortex and subthalamic nucleus, we recorded the responses of subthalamic nucleus neurons to electrical stimulation of the motor cortex in sham and 6-hydroxydopamine lesion rats (6-hydroxydopamine destroys dopaminergic neurons), and marked subthalamic cells with neurobiotin. Preliminar results demonstrate that lesion rats show a short latency response, compatible with a monosynaptic cortical input and a delayed response compatible with activation of the indirect pathway, as it was described for normal rats. This initial work will help to design future experiments aimed at studying the role of both pathways in the functional connectivity between the cortex and the subthalamic nucleus. Funded by: UBA, CONICET, FONCYT