Lab 11: Basal Ganglia System

Question 1

Overview of the Basal Ganglia

Answer 1

-as a group, these nuclei influence the selection and initiation of voluntary motor activity, primarily via influence on the frontal cortex.
their connections include:
A: motor areas of cortex—Striatum—-globus pallidus—-thalamus—-motor, premotor and supplementary motor cortex
B: globus pallidus—-subthalamic nucleus—–globus Pallidus, etc.
C: substantia nigra (pars compacta)—striatum

-They also function, through their influence on the frontal lobe, in some aspects of motivation, emotion and cognition

Question 2

Caudate Nucleus

Answer 2

Head: rostral expanded portion, lateral to the anterior horn of the lateral ventricle

Body: long part lateral to the body and atrium of the lateral ventricle

Tail: along the roof of the inferior horn of the lateral ventricle

Question 3

Caudate Nucleus Structure

Answer 3

A C-shaped structure with an expanded rostral extremity, the head which decreases in size to form a body and a tail. The head of the caudate nucleus bulges into the anterior horn of the lateral ventricle. The head and body have a close relationship to the lateral wall of the anterior horn and body of the lateral ventricle respectively, while the tail of the caudate nucleus is situated in the roof of the inferior horn of the lateral ventricle.

Question 4

Putamen Location

Answer 4

The putamen is lateral to the globus pallidus.
-the anterior limb of the internal capsule separates the lentiform nucleus (Putamen and globus pallidus) from the head of the caudate nucleus. Rostrally, the head of the caudate nucleus and the putamen are connected by cellular bridges and both become continuous rostroventrally

Question 5

Posterior Limb of the Internal Capsule Separates What 2 structure?

Answer 5

The thalamus and the lentiform nucleus

Question 6

Nucleus Accumbens

Answer 6

A component of the limbic part of the basal ganglia

Question 7

Anterior Limb of the Internal Capsule Separates what 2 structures?

Answer 7

The head of caudate and putamen

Question 8

Striatum

Answer 8

Consists of input nuclei (caudate and putamen) of the basal ganglia, receiving impulses from widespread areas of the cerebral cortex via corticostriate fibers

Question 9

Genu of the Internal Capsule

Answer 9

Area of internal capsule that is adjacent to the interventricular foramen

Question 10

Insular cortex

Answer 10

Covers lentiform nucleus at the level of the posterior limb of the internal capsule

Question 11

Globus Pallidus (external/lateral Segment)

Answer 11

An intrinsic nucleus that has output to the subthalamic nucleus

Question 12

Globus Pallidus (internal/medial segment)

Answer 12

An output nucleus,with important outflow to the thalamus

Question 13

Skeletomotor Loop

Answer 13

Cortex——putamen—–medial segment (GP)——VL of thalamus—–supplementary motor cortex

Question 14

Thalamus

Answer 14

Receives fibers from thalamic fasciculus

• VL nucleus belongs to the somatomotor system
• Dorsomedial nucleus is important for the relay of information to association and limbic areas of the frontal cortex

Question 15

Subthalamic Nucleus

Answer 15

Medial to the internal capsule

• is an intrinsic nucleus of the basal ganglia complex
• has input from the external (lateral) segment of globus pallidus and outflow to the internal (medial) segment of the Globus pallidus, with these connections traveling via the subthalamic fasciculus

Question 16

Substantia Nigra

Answer 16

Dorsal to the basis pedunculi in the midbrain

• is a nucleus of the basal ganglia complex
• includes an output Nucleus, the pars reticulata, that receives input from the striatum and that sends fibers to the thalamus as part of the oculomotor loop
• has an INTRINSIC nucleus, the pars compacta, that sends dopaminergic fibers to the striatum via the nigrostriatal pathway

Question 17

Tail of the Caudate

Answer 17

Dorsal to the temporal horn of the lateral ventricle

Question 18

Posterior Limb of the Internal capsule (in regards to basal ganglia circuitry)

Answer 18

-contains fibers from VA/VL to the cerebral cortex

Question 19

Supplementary Motor Cortex

Answer 19

Main target of the basal ganglia

Question 20

Prefrontal Cortex

Answer 20

Most of the frontal cortex that is rostral to the motor areas (premotor and primary motor cortex, supplementary motor cortex, frontal Eye field)

Question 21

Frontal Eye Field

Answer 21

-immediately rostral to the premotor cortex

Question 22

Tremor (fine oscillations)

Answer 22

Often at rest

Question 23

Athetosis

Answer 23

Slow, writhing movements of limbs, usually distal muscles

Question 24

Chorea

Answer 24

Rapid, flick-like movements of distal limbs and/or face

Question 25

Ballismus

Answer 25

Violent movements, mainly of proximal muscles

Question 26

Rigidity

Answer 26

Resistance to passive movement

Question 27

Bradykinesia

Answer 27

Slowness in movement