Basal Ganglia Flashcards
Primary cells in striatum, has dopamine receptors and special dendritic spines
Medium spiny neuron
Major role of indirect pathway
Inhibit unwanted movements
Does dopamine always have excitatory effect on target cells
NO
D1 receptors (direct pathways) excites
D2 receptors (indirect pathway) inhibits
Hypokinetic disorder
Not enough movement (Parkinson’s)
Output from basal ganglia
Tonic inhibitory (tonically active)
At rest, output is on
In Huntington’s disease, what causes degeneration of medium spiny neurons?
Misfolded huntingtin proteins
Basal ganglia influences what
Body movements, eye movements, cognition, mood
Dopamine influences direct and indirect pathways, the result of this on movement is what
Facilitates movement
Primary site of neuron degeneration in Parkinson’s
Substantial nigra
Job of basal ganglia
Movement selection
Major role of direct pathway
Select desired movements
Direct pathway
Cerebral cortex + signal to striatum
Striatum is - signal to GPi
GPi is - signal to thalamus (DISINHIBITORY)
Thalamus is + signal to motor cortex
Indirect pathway
Cerebral cortex is + signal to striatum
Striatum is - signal to GPe
GPe is - signal to STN
STN is + signal to GPi
GPi is - signal to thalamus
D1 receptors
Excitatory in presence of dopamine
Excites striatum - sends more inhibitory signals - disinhibits thalamus (more excitatory signals to motor cortex)
D2 receptors
Inhibitory in the presence of dopamine
Inhibits striatum - leads to GPi inhibiting thalamus - blocking movement
Hyperkinetic disorder
Too much movement (Huntington’s)
