LIFESCI 3K03 Lecture Notes - Lecture 15: Catatonia, Subthalamic Nucleus, Median Nerve
27 Feb 2018
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Document Summary
The efferent neurons of the globus pallidus and substantia nigra pars reticulata together allow the basal ganglia to influence the activity of upper motor neurons in the motor cortex and in the brainstem. Efferent neurons of both the globus palliduas and the substantia nigra pars reticulata are both gabaergic so the main output of the basal ganglia is inhibitory. In contrast to the msns mentioned previously, these neurons undergo high levels of spontaneous activity that prevent unwanted movement by tonically active cells in the thalamus and the superior colliculus. Neurons in the globus pallidus project to the motor cortex through the thalamus, whereas neurons in the substantia nigra pars reticulata have more direct access to the upper motor neurons. This is because many efferent neurons from the substantia pars reticulata synapse onto neurons in the superior colliculus that command head and eye movements without having to go through the thalamus.
