Basal Ganglia Flashcards

1
Q

What are the 4 functions of the basal ganglia

A

Subconscious planning, execution of motor function

Postural control

Complex unconscious, semi voluntary mv control

Non motor role via frontal lobe

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2
Q

Describe the groups of nuclei in the basal ganglia

A

Corpus striatum = striate nuclei + lentiform nuclei

Striate nuclei

  • Caudate
  • Putamen

Lentiform nuclei

  • GP
  • Putamen

Midbrain
-substancia nigra

Under thalamus
-subthalamic nuclei

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3
Q

Describe the direct pathway

What is the function of the direct pathway

A
Cortex
(Glu)
Putamen
(GABA)
GP int
(GABA)
Thalamus 
(Glu)
Cortex

Double inhibition => net excitation of cortex with glutamate => MOVEMENT

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4
Q

Describe the indirect pathway

What is the function of the indirect pathway

A
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

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5
Q

What is the role of dopamine
How is its function altered by receptors

How does this affect movement

A

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

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6
Q

What is the pathophysiology behind Parkinsons

What are the key symptoms

A

Insufficient dopamine => less glutamate released onto cortex

Shuffling Parkinsonian gait
Difficulty turning
No swinging of arms when walking

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