Exam #2: Basal Ganglia Flashcards
What are the two general functions of the basal ganglia?
1) Inhibition of involuntary movements at rest
2) Starting & stopping voluntary movements
Specifically, what movements does the basal ganglia inhibit?
- Tremors
- Chorea
- Tics
Specifically, what voluntary movements does the basal ganglia facilitate?
- Initiating movement
- Maintaining normal speed of movement
- Stopping movement
What are the five major nuceli that compose the basal ganglia?
1) Caudate nucleus
2) Putamen
3) Globus Pallidus
4) Subthalamic Nucleus
5) Substantia nigra
What are the two components of the “Lentiform Nucleus?”
- Putamen
- Globus Pallidus
*Note that Lentiform= “Lens-shaped” i.e. appearance on cross-section
What are the components of the “Corpus Striatum?’
- Caudate Nucleus
- Putamen
- Globus Pallidus (or pallidum)
What is the striatum?
- Putamen
- Caudate nucleus
**vs. Corpus Striatum that contains that Globus Pallidus as well
What is the Pallidum?
This is another name for the Globus Pallidus
What white matter tract runs between the lentiform & caudate?
Internal capsule
Where is the caudate in reference to the lateral ventricle?
Inferior and lateral
What is the striatum? What are the three major inputs to the striatum?
- Putamen & caudate nucleus
1) Cortex
2) Thalamus
3) Substantia nigra
What are the corticostriate fibers?
Input fibers from cortex to the striatum
What are the thalamostriate fibers?
Input fibers from the thalamus to the striatum
What are the nigrostriate fibers?
Input fibers from the SN to the striatum
What are the dopaminergic neurons from the SN primarily associated with behaviorly?
Movement
What does the loss of DA neurons in the SN result in, in PD?
Inability to INHIBIT unwanted movements
What is the two major outputs from the striatum?
Output from the Striatum is funneled to the:
1) GLOBUS PALLIDUS via striatopallidal fibers
2) SUBSTANTIA NIGRA via straitonigral fibers going to the SN
What are the two major inputs to the pallidum?
1) STRIATUM via the striatopallidal fibers
2) SUBTHALAMIC NUCLEUS via the subthalamaic fasiculus
What is the major output from the pallidum?
1) THALAMUS via pallidothalmic fibers
2) SUBTHALAMUS via pallidosubthalamic fibers i.e. the subthalamic fasiculus
What are the major divisions of the Pallidothalamic fibers? Where are they going?
1) LENTICULAR FASICULUS
2) ANSA LENTICULARIS
**BOTH are going to the THALAMUS
What nuclei are the Pallidothalamic fibers traveling to in the thalamus?
1) VENTRAL ANTERIOR nuclei of the THALAMUS
2) VENTRAL LATERAL nuclei of the THALAMUS
VA/VL–these are the motor nuclei of the thalamus
Draw the motor loop of the basal ganglia. What is the purpose of this loop?
Information relayed from basal ganglia to motor cortical areas
Cortex
- Supplementary motor cortex*
- Somatosensory cortex
- Primary motor cortex
- Premotor cortex
Striatum
Pallidum
Thalamus
Draw the association loop of the basal ganglia. What is the purpose of this loop?
Planning & direction of movement
Cortex
- Prefrontal cortex= decision making*
- Premotor cortex
- Posterior parietal cortex
Striatum
Pallidum
Thalamus
Draw the Oculomotor loop of the basal ganglia. What is the purpose of this loop?
Integration of eye movements & visual guidance
Cortex
- Frontal eye field*
- Prefrontal cortex
- Posterior parietal cortex
Striatum–>Superior colliculus
Pallidum
Thalamus
