Striatal evoked inhibition of identified nigro-thalamic neurons

Thirteen cells of the substantia nigra were found to be antidromically activated by VL stimulation and this study carried out on rats and cats to find out if the caudate nucleus can modulate the activity of the nigrothalamic pathway.

Abstract

The basal ganglia comprise a subcortical brain system through which the cerebral cortex affects behavior. The principal input structure is the striatum, whose GABAergic medium spiny neurons (MSNs) are the target of excitatory cortical and thalamic inputs. The output of the basal ganglia are GABAergic neurons in the internal segment of the globus pallidus and substantia nigra pars reticulata, which provide inhibition to the thalamus and midbrain motor areas including the superior colliculus and pedunculopontine nucleus. Activity in these output pathways is regulated by opponent effects of the two main MSN subtypes, those expressing the D1 dopamine receptor, which project directly to the output nuclei, and those expressing the D2 dopamine receptor, which project indirectly through the external segment of the globus pallidus and subthalamic nucleus. In addition, the striatum is organized into patch and matrix compartments, which differentially regulate substantia nigra pars compacta dopamine neurons and GABAergic output pathways.