Basal Ganglia Flashcards Preview

Neuroanatomy > Basal Ganglia > Flashcards

Flashcards in Basal Ganglia Deck (30)
Loading flashcards...
1
Q

What is the basal ganglia?

A

Collection of subcortical nuclei that are involved in control of movement

2
Q

What five nuclei are part of the basal ganglia?

A

The caudate, putamen, globus pallidus, subthalamic nucleus and substansia nigra

3
Q

Why is the amygdala not usually counted as basal ganglia?

A

It is functionally part of limbic system

4
Q

Which nuclei in basal ganglia receive most input?

A

The putamen and caudate nucleus

5
Q

Which nuclei make up the striatum?

A

The putamen and caudate nuclei- similar anatomically and have similar functional role

6
Q

What project to the striatum?

A

All cortical areas involved in planning and execution of movements

7
Q

Where does the striatum primarily project to?

A

Globus pallidus and substansia nigra

8
Q

Which nuclei are referred to as lenticular nucleus?

A

Globus pallidus and putamen

9
Q

What is the globus pallidus divided into?

A

The internal and external segments

10
Q

What sends the main projection out of basal ganglia to thalamus?

A

The globus pallidus internal segment and the substansia nigra pars reticulata

11
Q

How does striatal information reach globus pallidus internal segment?

A

Two main pathways: direct and indirect pathways

12
Q

What is the ansa lenticularis?

A

conveys information from GPi to the motor thalamus (VLN)- loops under posterior limb of internal capsule

13
Q

How does information from more caudal part of globus pallidus reach VA/VL nuclei of thalamus?

A

The lenticular fasciculus- travel through the posterior limb of internal capsule

14
Q

How many loops are there?

A

4- motor, cognitive, limbic and occulomotor

15
Q

What is the consequence of the direct pathway?

A

It increases the excitatory drive from thalamus to cortex

16
Q

What neurotransmitter do the cortical projections to striatum use?

A

Glutamate

17
Q

What neurotransmitter do the striatal cells projecting to GPi use?

A

GABA

18
Q

What neurotransmitter do the neurons projecting from GPi to thalamus use?

A

GABA

19
Q

What is the result of the direct pathway?

A

The cortical signals excite striatal neurons via glutamate- the results in inhibition of GPi via striatum which uses GABA- more inhibition of GPi means less inhibition of thalamus which increases motor activity

20
Q

Where do striatal neurons project to in the indirect pathway?

A

GPe

21
Q

What additional nucleus is involved in the indirect pathway?

A

Subthalamic Nucleus

22
Q

What is the route of the indirect pathway?

A

cortex (glutamate)- striatum (GABA)- GPe (GABA)- subthalamic nucleus (glutamate)- GPi (GABA)- VA/VL in thalamus (glutamate)- motor cortex

23
Q

What is the consequence of the indirect pathway?

A

Decrease excitatory drive from thalamus to cortex

24
Q

What is function of nigrostriatal axon terminals?

A

Release dopamine into striatum

25
Q

What is the effect of dopaminergic nigrostriatal projects?

A

Increase motor activity- has excitatory effect on cells in striatum involved in direct pathway- has inhibitory effect on striatal cells of indirect pathway

26
Q

What are local circuit neurons?

A

population of cholinergic neurons that do not leave striatum

27
Q

What are the actions of cholinergic neruons in striatum?

A

Inhibit striatal cells of direct pathway and excite striatal cells of indirect pathway- decreases motor activity

28
Q

What occurs as result of damage to basal ganglia?

A

Hyperkinesia (increased movement) or hypokinesia (decreased movement)

29
Q

What are Lewy bodies?

A

Accumulation of protein in degenerating nigral dopaminergic cells

30
Q

Name one hyperkenesic and one hypokinesic disorder.

A

Parkinson’s (hypo) and Huntingtons (Hyper)