Control of Movement 4 Flashcards
Name the input nuclei of the basal ganglia
Caudate nucleus
Putamen
Name the intrinsic nuclei of the basal ganglia
External segment of globus pallidus
Subthalamic nucleus
Substantia nigra (pars compacta)
Name the output nuclei of the basal ganglia
Internal segment of the globus pallidus Substantia nigra (pars reticulate)
Which NT does the cerebral cortex release to excite the putamen?
Glutamate
What effect does the putamen exert on the globus pallidus and how?
Inhibitory via GABA
What effect does the medial lobe of GP have on the thalamus normally?
Inhibits activity via GABA
What effect does the medial lobe of GP have on the thalamus in the direct pathway?
Increases thalamic activity (GP been inhibited, and it usually inhibits thalamus)
What is the overall effect of the direct pathway?
Increase in movement
What effect does the putamen have on the lateral lobe of the GP?
Inhibitory via GABA
What effect does the lateral lobe of GP usually have on the subthalamic nucleus?
Inhibition via GABA
What effect does lateral lobe of GP have on the subthalamic nucleus in the indirect pathway?
As lateral lobe inhibited, (removal of inhibition on subthalamic) increase in activity of subthalamic nucleus
What effect does the subthalamic nucleus have on the medial lobe of GP?
Excitation
What happens in the indirect pathway regarding the medial lobe of GP?
Increase in activity of medial lobe of GP by subthalamic nucleus which results in increased inhibition of thalamus
What is the overall effect of the indirect pathway?
Decrease in movement
What effect do D1 receptors have on the basal ganglia?
Enhance direct pathway increasing movement
What effect do D2 receptors have on the basal ganglia?
Inhibit indirect pathway increasing movement
Where is dopamine released from?
Pars compacta of substantia nigra
What are the 4 main features of parkinsonism? (TRAP)
Tremor
Rigidity
Akinesia
Posture
Which pathway is affected in Parkinsons?
Direct - hypokinetic
What is hemiballismus?
Lesion of subthalamic nucleus resulting in no stimulation of GPi resulting in violent projectile movements
Where are lesions that cause chorea?
Putamen
Which is the genetic cause of Huntington’s chorea?
Excessive CAG repeats on chromosome 4
What is the physiological cause of chorea?
Loss of GABA neurons in putamen that project to GBe (inhibition of indirect pathway)
What is athetosis?
Lesion of globus pallidus which causes abnormal movements (hyperkinetic)
What causes the pathology in Wilson’s disease?
Accumulation of copper in lentiform nucleus
Which basal ganglia structure is affected in Wilson’s disease?
Lentiform nucleus
What are the main symptoms of Wilson’s disease?
Dystonia
Tremor
What is the name of the malformed protein in Hungtinton’s disease?
Huntingtin
What is the physiological cause of Huntington’s disease?
Loss of encephalin and GABA secreting neurons in the neostriatum leading to decrease in indirect pathway
What are the features of a basal ganglia lesion?
Contralateral signs
Increased tone
Normal reflexes
What is dystonia?
Lesion of lentiform nucleus that causes muscle contraction and abnormal posture
