The Basal Nuclei

Question 1

The dorsal basal nuclei:

Answer 1

• caudate and putamen (neostriatum)

- globus pallidus (paleostriatum)

Question 2

List the nuclei functionally associated with the dorsal basal nuclei.

Answer 2

• substantia nigra
• subthalamic nucleus
• parabrachial pontine reticular formation (containing pedunculopontine tegmental nucleus)

Question 3

The ventral basal nuclei:

Answer 3

• nucleus accumbens
• substantia innominata
• nucleus basalis of Meynert
• olfactory tubercle

Question 4

Where is the ventral region located?

Answer 4

Inferior to the anterior commissure

Question 5

The telencephalic regions of basal nuclei (caudate, putamen, globus pallidus) are supplied by:

Answer 5

• Medial striate a.
• Lenticulostriate aa. (branches of M1)
• Anterior choroidal a.

Question 6

The diencephalic and mesencephalic regions are supplied by:

Answer 6

• Posteromedial branches of P1

- Posterior communicating a.

Question 7

The striatal complex is composed of:

Answer 7

• Neostriatum (caudate nucleus and putamen)

- Ventral striatum (nucleus accumbens and portions of olfactory tubercle)

Question 8

What are patches (striosomes)?

Answer 8

Defining characteristic of striatal complex; acetylcholinesterase-poor regions and surrounded by matrix (lots of acetylcholine)

Question 9

Most neurons in the neostriatum are _______

Answer 9

Medium spiny neurons

Question 10

Medium spiny neurons use:

Answer 10

GABA (also substance P and enkephalin)

Require afferents mostly for activation

Question 11

Axons of the medium spiny fibers are…

Answer 11

The striatopallidal fibers (efferents of neostratum)

Question 12

Huntington disease is characterized by:

Answer 12

Loss of medium spiny fibers and acetylcholine-containing neurons in striatal complex

Question 13

The pallidal complex is composed of:

Answer 13

• Globus pallidus
• Ventral pallidum (mostly substantia innominata)

GABAergic and largely spontaneous

Question 14

What is an important cell group in the substantia innominata?

Answer 14

Basal nucleus of Meynert

Acetylcholine-containing neurons that are lost in Alzheimer’s Disease (also lost from other places)

Question 15

The globus pallidus has medial and lateral segments. Medium spiny neurons from the striatum that project to the medial segment and substantia nigra use______; those that project to the lateral segment use ______

Answer 15

GABA and substance P

GABA and enkephalin

Question 16

Subthalamic neuron use the neurotransmitter ________

Answer 16

glutamate

Cells are usually inhibited by external pallidal segment.

Question 17

The nigral complex is composed of:

Answer 17

• Substantia nigra

- Ventral tegmental area

Question 18

The substantia nigra can be divided into:

Answer 18

• Pars compacta

- Pars reticulata

Question 19

Pars compacta secretes ______ which travels via _______ to inhibit or excite striatal neurons

Answer 19

dopamine; nigrostriatal fibers

Question 20

Pars reticulata neurons are ______

Answer 20

GABAergic (inhibitory)

Question 21

Pars reticulata and pars compacta regulate one another via…

Answer 21

dopamine and GABA

Question 22

Neurons in the _____ inhibit the pars compacta

Neurons in the _____ inhibits the pars reticulata

Answer 22

patches

matrix

Question 23

What are the major functional pathways of the basal nuclei?

Answer 23

• Motor loop
• Executive loop
• Motivational loop
• Visuomotor loop

Question 24

Motor loop originates and terminates in…

Answer 24

Supplementary motor, primary motor, and premotor cortices

Question 25

Executive loop originates and terminates in…

Answer 25

Dorsolateral prefrontal and posterior parietal cortices

Question 26

Motivational loop originates and terminates in…

Answer 26

Lateral orbitofrontal cortex, anterior cingulate cortex, medial prefrontal cortex, amygdala, and hippocampus

Question 27

Visuomotor loop originates and terminates in…

Answer 27

Visual portions of the temporal cortex and the frontal eye fields