Basal Ganglia Flashcards
What are the 4 functions of the basal ganglia
Subconscious planning, execution of motor function
Postural control
Complex unconscious, semi voluntary mv control
Non motor role via frontal lobe
Describe the groups of nuclei in the basal ganglia
Corpus striatum = striate nuclei + lentiform nuclei
Striate nuclei
- Caudate
- Putamen
Lentiform nuclei
- GP
- Putamen
Midbrain
-substancia nigra
Under thalamus
-subthalamic nuclei
Describe the direct pathway
What is the function of the direct pathway
Cortex (Glu) Putamen (GABA) GP int (GABA) Thalamus (Glu) Cortex
Double inhibition => net excitation of cortex with glutamate => MOVEMENT
Describe the indirect pathway
What is the function of the indirect pathway
Cortex (Glu) Putamen (GABA) GP ext (GABA) STN (Glu) GP int (GABA) Thalamus (Glu) Cortex
Triple inhibition => net inhibition of cortex with less glutamate => NO MOVEMENT
What is the role of dopamine
How is its function altered by receptors
How does this affect movement
D1 => stimulatory
D2 => inhibitory
D1 stimulated in the direct pathway => net increase in glutamate
D2 stimulated in indirect pathway => net increase in glutamate
Indirect pathway inhibited so MOVEMENT IS INITIATED
What is the pathophysiology behind Parkinsons
What are the key symptoms
Insufficient dopamine => less glutamate released onto cortex
Shuffling Parkinsonian gait
Difficulty turning
No swinging of arms when walking