export_basal ganglia

Question 1

What are the components of the basal ganglia

Answer 1

1. Corpus striatum - neostriatum and paleostriatum
2. Amygdala
3. Subthalamic nucleus
4. Substantia nigra

Question 2

Neostriatum =

Answer 2

Caudate and putamen

Question 3

Paleostriatum =

Answer 3

Globus Pallidus

Question 4

Corpus Striatum =

Answer 4

Neo and paleostriatum

= Caudate, putamen and basal ganglia.

Question 5

Achristriatum =

Answer 5

Amygdala

Question 6

Lentiform nuclei =

Answer 6

Putamen and globus pallidus

Question 7

Diencephalic nucleus =

Answer 7

Paleostriatum and subthalamic nucleus

Question 8

Telencephalic nucleus =

Answer 8

Neostriatum and archistriatum

Question 9

What are the components of the caudate nucleus

Answer 9

1. Head - contiguous with the APF
2. Body - separated from the thalamus by the stria terminalis and the terminal vein
3. Tail - In the roof of the temporal horn near the amygdala
4. Nucleus Accumbens - located where the caudate and putamen meet anteriorly

Question 10

Which fibers/tracts send input to the striatum

Answer 10

1. Corticostriate
2. Amygdalostriate
3. Thalamostriate
4. Nigrostriatal
5. Raphe nucleus

Question 11

Corticostriatal input

Answer 11

1. Area 4 to the bilateral putamen
2. Premotor cortex to the ipsilateral caudate and putamen
3. Prefrontal cortex to the caudate

Question 12

Amygdalostriatal input

Answer 12

Amygdala to the caudate and putamen.

Question 13

Thalamostriatal input.

Answer 13

1. Intralaminar CM nucleus to the putamen

2. Parafascicular nucleus to the caudate

Question 14

Nigrostriatal input

Answer 14

Substantia nigra to the caudate and the putamen. Transmits inhibitory dopaminergic signals.

Question 15

Raphe nucleus input to the striatum

Answer 15

Transmits inhibitory serotonergic signals to the striatum.

Question 16

What are the three major striatal output fibers?

Answer 16

1. Striatonigral
2. Striatopallidal
3. Nigrothalamic

Question 17

Striatonigral fibers ouput:

Answer 17

Head of the caudate to the substantia nigra pars reticulata.

Question 18

Striatopallidal fibers output:

Answer 18

Inhibitory/GABA output from the caudate/putamen to the globus pallidus interna.

Question 19

Nigrothalamic fibers output:

Answer 19

Terminate in the VA, VL, MD fibers. Use GABA as neurotransmitters.

Question 20

What are the three medullary lamina

Answer 20

1. Lateral medullary lamina lies between the putamen and the globus pallidus
2. Medial medullary lamina - divides the medial and lateral GP
3. Accessory medullary lamina - divides the MGP into the inner and outer segments.

Question 21

Input to the globus pallidus

Answer 21

Striatum to the LGP - GABA/enkephalin
Striatum to the MGP - Substance P

Lateral part of the subthalamus reciprocal glutamergic input to the LGP.

Medial part of the subthalamus reciprocal glutamergic input to the MGP

Question 22

Which neurotransmitters are decreased in Huntington’s disease and to which regions.

Answer 22

Substance P and enkephalin.

Globus Pallidus and substantia nigra.

Question 23

What are the four output bundles/tracts from the globus pallidus.

Answer 23

1. Ansa lenticularis
2. Lenticular fasciculus
3. Thalamic fasciculus
4. Pallidosubthalamic fibers.

Question 24

Features of the ansa lenticularis

Answer 24

Major output tract of the globus pallidus

From the MGP around the IC to Forel’s field H1 - FFH1 - and the prerubral field.

Question 25

Features of the lenticular fasciculus 

Answer 25

Also known as FFH2 fibers. They pass from the MGP through the IC to join the ansa lenticularis in Forel's field and then enters the thalamic fasciculus.

Question 26

Features of the thalamic fasciculus

Answer 26

Also known as the FFH1 fibers. This bundle is composed of the joined ansa lenticularis, lenticular fasciculus, and cerebellothalamic tract which all project to the thalamic VA and VL.

Question 27

Features of the pallidosubthalamic fibers

Answer 27

1. LGP to the subthalamus 2. MGP to the stria medularis and lateral habenulum 3. GP to the VA, VL and CM.

Question 28

Where is the subthalamus located?

Answer 28

Posterolateral to the hypothalamus, ventral to the thalamus and medial to the internal capsule - lesions here cause contralateral hemiballismus

Question 29

What are some key components of the subthalamic nucleus

Answer 29

1. Subthalamic nuclei of Luys - located over the rostra SN 2. Zona incerta - grey matter between the thalamic and lenticular fasciculi. Motor input 3. Sensory fasciculi - medial lemniscus, spinothalamic, and trigeminothalamic tracts --> VP thalamus 4. Cerebellar and globus pallidus fibers which run to the thalamus.

Question 30

What are the three major bundles within the subthalamic fasciculus 

Answer 30

1. Dentothalamic fibers --> FFH1 via the red nucleus to enter the VL 2. Ansa lenticularis 3. Lenticular fascicularis --> FFH2

Question 31

Input to subthalamic nucleus

Answer 31

Prefrontal, premotor, and motor cortex LGP CM and PF thalamic nuclei Pedunculopontine nuclei

Question 32

Output of the subthalamic nucleus

Answer 32

1. LGP - MAJOR 2. MGP 3. SN

Question 33

What is the major neurotransmitter of the subthalamic nucleus

Answer 33

Glutamate

Question 34

Input and output of the Claustrum

Answer 34

Input: Lateral hypothalamus, thalamic CM nucleus, and locus ceruleus. Output: Reciprocal connections with area 6.

Question 35

Input and output of the substantia nigra

Answer 35

The striatum to the SN pars reticulata. The SN does not have any output to the GP. The SNpc sends its output to the striatum. The SNpr sends its output to the thalamus and the pedunculopontine nucleus.

Question 36

What is the role of the corpus striatum

Answer 36

It sends inhibitory output to the MGP and the SNpr which inhibits the thalamic output to the premotor and SMA but not area 4. 

Question 37

What is the putamen BG circuit.

Answer 37

It is involved in discrete motor movements. Fibers from the motor and somatosensory cortex --> putamen --> GP --> thalamus ---> supplementary motor cortex. 

Question 38

What is the caudate BG circuit

Answer 38

It is involved with cognitive function. Fibers from cortical association areas --> caudate --> GP --> thalamus --> supplementary motor cortex. 

Question 39

Summary of the BG pathways

Answer 39

1. Striatum has reciprocal connections with the SN 2. GP has reciprocal connection with the ST 3. LGP--> ST 4. MGP --> VL, VA and CM of the thalamus 5. There are no afferent fibers from the cortex or thalamus to the GP. 6. SNpc inhibits the putamen which inhibits the GP which inhibits the thalamus.