Basal Ganglia

Question 1

Which two parts of the corpus striatum are functionally similar ?

Answer 1

Caudate nucleus & Putamen

Question 2

What constitutes the Lentiform nucleus?

Answer 2

Putamen & Globus Pallidus

Question 3

What are the Caudate nucleus & Putamen altogether known as?

Answer 3

Neostriatum/striatum

Question 4

What is the basal ganglia made up of?

Answer 4

Corpus striatum & Amygdala

Question 5

What are the Caudate nucleus, Globus Pallidus & Putamen called altogether?

Answer 5

Corpus striatum

Question 6

What constitutes the Paleostriatum?

Answer 6

Globus Pallidus

Question 7

What is the most ventral part of the striatum called?

Answer 7

Nucleus Accumbens

Question 8

Which integrative ‘system’ is Nucleus Accumbens a part of?

Answer 8

Limbic

Question 9

What is the claustrum & where is it found?

Answer 9

It is a ‘sliver’ of gray matter found sandwiched within the white matter lateral to the putamen.

Question 10

What is the structure that separates the head of the Caudate Nucleus from the Putamen?

Answer 10

Anterior Limb of the Internal Capsule

Question 11

Where is the Substantia Innominata?

Answer 11

Basal part of rostral (towards the head) forebrain BENEATH the Corpus Striatum

Question 12

Name an important group of neurones in the Substantia Innominata

Answer 12

Nucleus Basalis (project widely to cerebral cortex and use ACh as neurotransmitter - main neurones to undergo degen. in Alzheimer’s disease)

Question 13

What is the ‘input’ portion of the Corpus Striatum?

Answer 13

Caudate Nucleus & Putamen

Question 14

What are the three MAIN striatal afferents?

Answer 14

Corticostriatal (frontal lobes & parietal lobes)
Thalamostriatal (intralaminar nuclei of thalamus)
Nigrostriatal (pars compacta of substantia nigra)

Question 15

Name the neurotransmitter released by the corticostriatal fibres

Answer 15

Glutamic acid

Question 16

Name the neurotransmitter released by the thalamostriatal fibres

Answer 16

Glutamic acid

Question 17

Name the neurotransmitter released by the nigrostriatal fibres

Answer 17

Dopamine

Question 18

Is glutamic acid excitatory or inhibitory?

Answer 18

Excitatory

Question 19

Is dopamine excitatory or inhibitory?

Answer 19

Both - depending on which receptor it binds to [D1 or D2].

Question 20

Name two (not as important) striatal afferents?

Answer 20

Mesolimbic/mesostriatal fibres (From VTA to Nucleus Accumbens)
Fibres from Raphe Nuclei (Found all along the brainstem)

Question 21

Name the neurotransmitter released by mesolimbic/mesostriatal fibres

Answer 21

Dopamine

Question 22

Name the neurotransmitter released by the Raphe nuclei

Answer 22

Serotonin

Question 23

Is serotonin excitatory or inhibitory?

Answer 23

Excitatory

Question 24

What is the special name of the type of neurones that are striatal efferents?

Answer 24

Medium spiny neurones

Question 25

What are the three regions striatal efferents project to?

Answer 25

Internal Globus Pallidus, External Globus Pallidus, Pars Reticularis of Substantia Nigra

Question 26

Which neurotransmitter do striatopallidal and striatonigral fibres use?

Answer 26

GABA

Question 27

IS GABA excitatory or inhibitory?

Answer 27

Inhibitory

Question 28

Which neuropeptide(s) do neurones projecting to the Internal Globus Pallidus & Pars Reticulata contain?

Answer 28

Dynorphin & Substance P

Question 29

Which neuropeptide(s) do neurones projecting to the External Globus Pallidus contain?

Answer 29

Met-enkephalin

Question 30

Which structure is the Internal Globus Pallidus and Pars Reticulata of the Substantia Nigra separated by?

Answer 30

Posterior limb of the internal capsule

Question 31

What is regarded as the 'output' region of the basal ganglia?

Answer 31

Internal/Medial Globus Pallidus & Pars Reticulata of the Substantia Nigra

Question 32

What are the two pallidal afferents?

Answer 32

Striatopallidal & subthalamopallidal fibres

Question 33

Which part of the brain is the subthalamic nucleus found? | Eg. Forebrain, midbrain, hindbrain

Answer 33

Forebrain ---> Caudal diencephalon

Question 34

Where is the subthalamic nucleus located in relation to the thalamus and internal capsule?

Answer 34

Beneath the thalamus. | Lies against the medial surface of the internal capsule.

Question 35

Describe the pathway of the subthalamopallidal fibres

Answer 35

- Starts in the subthalamic nucleus. - Pass LATERALLY through the internal capsule. - As they pass through the internal capsule, they contribute to the fibre system: subthalamic fasciculus. - They terminate in both internal and external globus pallidus but there is more dense termination in the internal globus pallidus.

Question 36

Which neurotransmitter(s) do subthalamopallidal neurones use?

Answer 36

Glutamic acid

Question 37

Where else does the subthalamic nucleus send afferents?

Answer 37

Pars reticulata of the substantia nigra

Question 38

Where do the efferent fibres from the external/lateral globus pallidus project to?

Answer 38

Subthalamic nucleus

Question 39

Describe the path taken by the pallidosubthalamic fibres

Answer 39

- Start in the lateral/external globus pallidus | - Pass MEDIALLY through the internal capsule in the subthalamic fasciculus.

Question 40

What neurotransmitter(s) do the pallidosubthalamic fibres use?

Answer 40

GABA

Question 41

What is the overall 'output' of the 'output region' when excited? - Excitatory or Inhibitory?

Answer 41

Inhibitory

Question 42

What is the main efferent projection and the 'accessory' efferent projection of the internal globus pallidus & pars reticulata?

Answer 42

Primarily: THALAMUS | Some fibres: Brain Stem Tegmentum

Question 43

What is the brain stem tegmentum?

Answer 43

An 'area' of the brain stem which is mainly the posterior section of it when looking at it head on.

Question 44

What neurotransmitter(s) do the palllidothalamic and nigrothalamic fibres use?

Answer 44

GABA

Question 45

Which nuclei in the thalamus do the pallidothalamic and nigrothalamic fibres mainly project to?

Answer 45

- ventral lateral - ventral anterior - centromedian

Question 46

What are the two main routes taken by pallidothalamic fibres?

Answer 46

- As part of the ansa lenticularis | - As part of the lenticular fasciculus

Question 47

Describe the route when pallidothalamic fibres run as the ansa lenticularis

Answer 47

- Start in the internal globus pallidus - Pass around the anterior margin of the internal capsule as ANSA LENTICULARIS - Fibres course medially. - Then, loop dorsally and laterally as the THALAMIC FASCICULUS. - Enter the thalamus from its VENTRAL aspect.

Question 48

Describe the route when pallidothalamic fibres run as the lenticular fasciculus

Answer 48

- Start in the internal globus pallidus - Pass through the internal capsule as the LENTICULAR FASCICULUS. - Fibres course medially. - Then, loop dorsally and laterally as the THALAMIC FASCICULUS. - Enter the thalamus from its VENTRAL aspect.

Question 49

Which cellular region do pallidothalamic fibres circumnavigate when making their way to their destination?

Answer 49

Zona Incerta of the subthalamus - lies between the thalamus and subthalamic nucleus.

Question 50

Where do the thalamus' target nuclei in the output of the basal ganglia project to in the brain? Excitatory or inhibitory?

Answer 50

- Motor regions of the frontal lobe - primary motor and supplementary motor cortices. - Excitatory

Question 51

Efferent pallidal and efferent nigral fibres run to the brain stem tegmentum. Where in that area do the fibres terminate?

Answer 51

The fibres pass caudally to.. | Nucleus tegmenti peduncolopontinus --> Pedunculopontine nucleus.

Question 52

Where exactly is the peduncolopontine nucleus situated?

Answer 52

Boundary between midbrain and pons - surrounding superior cerebellar peduncle

Question 53

Projections to the pars reticulata and internal globus pallidus are somatotopically organised. -Which movements are pallidal efferent neurones associated with?

Answer 53

Limb movements.

Question 54

-Which movements are nigral efferent neurones associated with?

Answer 54

Axial musculature - including extraocular muscles.

Question 55

Like palidal efferents, nigral efferents go to the ventral lateral thalamus, brain stem reticular formation (including pedunculopontine nucleus) and which other destination?

Answer 55

Superior colliculus