27 - Basal Ganglia

Question 1

What do the Basal Ganglia Modulate?

Answer 1

Descending Cortical and Brainstem Pathways

Question 2

Cerebellum

Answer 2

Coordination

Question 3

Basal Ganglion

Answer 3

Selection & Initiation

Question 4

Basal Ganglion projects to

Answer 4

Cortical Motor Areas (Premotor & Motor)

Brainstem

Question 5

Basal Ganglia Input Nuclei

Answer 5

Caudate Nucleus
Putamen
Nucleus Accumbens (NA)

Question 6

Basal Ganglia Output Nuclei (to Thalamus)

Answer 6

Internal Segment of Globus Pallidus (GPi)
Substantia Nigra Pars Reticulata (SNpr; GABA)
Ventral Pallidum (VP)

Question 7

Basal Ganglia Intrinsic Nuclei

Answer 7

External Segment of Globus Pallidus (GPe)
Substantia Nigra Pars Compacta (SNpc; dopamine)
Ventral Tegmental Area (VTA; dopamine)
Subthalamic Nucleus (STN)

Question 8

A lesion in where causes Parkinson’s?

Answer 8

Substantia Nigra Pars Compacta

Somewhere else in the Direct Pathway

Question 9

Basic Flow of Information

Answer 9

Cortex
Basal Ganglia
Thalamus (VA/VL, MD)
Cortex

Question 10

Cerebellum sends primary projections where?

Answer 10

VL

Question 11

Basal Ganglia sends primary projections where?

Answer 11

VA

Question 12

Limb Movement - Direct Pathway

Answer 12

Facilitates Movement
Excitatory
Enhances Motor Activity

Question 13

Limb Movement - Indirect Pathway

Answer 13

Anti-Facilitates Movement

Reduces input to the Thalamus

Question 14

Limb Movement Pathways

Answer 14

Excitatory inputs from the Cortex converge on the Striatum and activate the direct and indirect pathways, which result in different outputs to the thalamus

Question 15

Striatum

Answer 15

Caudate
Putamen
Nucleus Accumbens (NA)

This is the same thing as the Input Nuclei of the Basal Ganglia.

Question 16

Lesions of the Direct Pathway lead to

Answer 16

Parkinson’s (Hypokinetic)

Question 17

Lesions of the Indirect Pathway lead to

Answer 17

Huntington’s (Hyperkinetic)

Question 18

Lesions of the Subthalamic Nucleus lead to

Answer 18

Hemiballism

Uncontrolled ipsilateral flailing of the shoulder and upper arm

Question 19

Cortex-Basal Ganglia-Thalamus Loops

Answer 19

Skeletomotor
Oculomotor
Cognitive
Emotional (Limbic)

Question 20

Principal Input Nucleus of the Skeletomotor Loop

Answer 20

Putamen

Question 21

Skeletomotor Loop

Answer 21

Putamen
GPi/SNpr
VA
SMA/PMC/MC
Putamen

Question 22

Oculomotor Loop

Answer 22

Caudate (Body)
SNpr/GPi
VA/MD
FEF
Caudate (Body)

Question 23

Cognitive Loop

Answer 23

Caudate (Head)
SNpr/GPi
VA/MD
FAC
Caudate (Head)

Question 24

Emotional (Limbic)

Answer 24

Nucleus Accumbens
VP/GPi/SNpr
MD
LAC/ACG
Nucleus Accumbens

Question 25

FEF

Answer 25

Frontal Eye Field

Question 26

Lenticular Nucleus

Answer 26

Putamen | Globus Pallidus

Question 27

Huntington's Signs on Imaging

Answer 27

``` Cortical Atrophy Caudate Atrophy Putamen Atrophy Enlarged Ventricles Lateral Edge Flattened ```

Question 28

If you only see one division of the Globus Pallidus, which one is it?

Answer 28

External!!!

Question 29

Two types of output from the GPi to the Thalamus

Answer 29

Ansa Lenticularis | Lenticular Fasciculus

Question 30

Ansa Lenticularis

Answer 30

Originates - Ventral aspect of GPi Courses ventrally toward midline Hooks around Internal Capsule (posterior limb) Courses towards the thalamus

Question 31

Lenticular Fasciculus

Answer 31

Arises - Dorsal aspect of GPi Small fascicles of fibers pierce directly through Internal Capsule rostral to STN Collect to form a well-defined bundle

Question 32

What is the difference between the information in the Ansa Lenticularis and the Lenticular Fasciculus?

Answer 32

Nothing! They carry the same information!

Question 33

Where do the Ansa Lenticularis and Lenticular Fasciculus enter the Thalamus?

Answer 33

Thalamic Fasciculus They join fibers from the cerebellar nuclei They terminate in VA/VL

Question 34

Where do the Ansa Lenticularis and Lenticular Fasciculus rejoin to form the Thalamic Fasciculus??

Answer 34

Medial to the Zona Incerta

Question 35

The most peripheral nucleus of the Thalamus

Answer 35

Zona Incerta