4.2 neuro - basal nuclei Flashcards
What are basal nuclei
collection of interconnected subcortical nuclei that function as a central link in the part of the motor system that translates the desire to move into action, organ of habit
true/false The basal nuclei make direct / indirect synaptic connections with motor neurons in the spinal cord or brainstem
false
What nuclei are included in the basal nuclei
Caudate nucleus, putamen, globus pallidus, substantia nigra, subthalamic nucleus
The caudate nucleus and putamen make up the __
striatum
The globus pallidum is a part of what structure
pallidum
The substantia nigra is a part of what structure
brain stem, midbrain
The subthalamic nucleus is a part of what structure
diencephalon
What are the two subdivisions of the globus pallidus
internal and external
What does the direct pathway of basal nuclei do
facilitate appropriate motor programs
What does the indirect pathways of basal nuclei do
inhibits competing motor programs
Explain the direct pathway of basal nuclei
cortex stimulates the striatum, striatum inhibits the globus pallidus, this blocks globus pallidus inhibition of the thalamus, thalamus signals backs to cortex
Explain the indirect pathway of basal nuclei
cortex stimulates the striatum, striatum inhibits the globus pallidus, globus pallidus inhibits the subthalamic nucleus, subthalamic nucleus stimulates the globus pallidus, stimulated globus pallidus inhibits the thalamus, thalamus does not stimulate the cortex
Net effect of the indirect pathway of basal nuclei
decrease the activity of the thalamus and consequent excitation of the cerebral cortex
Net effect of the direct pathway of basal nuclei
increase the activity of the thalamus and the consequent excitation of the cerebral cortex
Function of the substantia nigra
source of dopamine to the striatum, keep the striatum ready to go, without it the striatum can’t respond to the cortical input
