6 - Basal Ganglia Flashcards
What are the structures in the basal ganglia
Caudate Putamen Globus pallidus i and e Substantia nigra subthalamic nucleus
Nucleus accumbens
Ventral striatum
Dorsal striatum
Caudate and putamen
Function of the basal ganglia
regulate intensity of slow movements
inhibit antagonistic and unnecessary movement
regulate attention and cognition
motor program switch
Medium spiny neurons
Type of neuron in the BG
Input is via glutamate
output via gaba
What is convergence
ability to integrate lots of information from many neurons and relay that to a decreasing number of neurons
Direct pathway
Excitatory to the motor thalamus by disinhibition
Striatum –> GPI –> Thalamus –> Motor cortex
What type of neurons does the striatum and GP contain?
GABAergic
Which nucleus has tonic inhibition on the motor thalamus?
Globus pallidus interna
Indirect pathway
Striatum –> External Gp –> STN –> Internal globus pallidus
Inhibitory to the thalamus
Increases the tonic inhibition of the GPi
At rest what pathway is active?
Indirect is active - inhibiting the GPext
Function of BG
deciding on the initiation and sequencing of voluntary movement
What pathway is active when you want to change your action?
Direct pathway
Dopamine action on direct pathway
increases action
via D1 receptors
activates motor program change
Dopamine action on indirect pathway
decreases action
via D2 receptors
blocks motor program change
