Diencephalon and Basal Ganglia

Question 1

What does subcortical mean?

Answer 1

beneath the cerebral cortex

Question 2

What are the major subcortical structures of the brain?

Answer 2

• diencephalon
• basal ganglia

Question 3

What color brain matter is the diencephalon?

Answer 3

nuclei gray matter

Question 4

What are the 4 parts of the diencephalon?

Answer 4

• epithalamus
• thalamus
• subthalamus
• hypothalamus

Question 5

What are the 5 parts of the basal ganglia?

Answer 5

• caudate
• putamen
• globus pallidus
• subthalamic nucleus
• substantia nigra

Question 6

What is the epithalamus and what is its role?

Answer 6

• single midline structure also called the pineal gland
• secretes melatonin (sleep-wake cycle)
• has no neural output

Question 7

What is the thalamus and what is its role?

Answer 7

large bilateral structure that serves as a relay and association center

Question 8

What is the role of the hypothalamus?

Answer 8

mediate complex functions

Question 9

What are the implications of a stroke in the thalamus?

Answer 9

a small stroke in the thalamus can have big effects due to high specificity

Question 10

What is the role of the ventral anterior and ventral lateral nuclei of the thalamus?

Answer 10

• motor nuclei (LCST and ACST)

Question 11

What is the role of the ventral posterolateral nucleus of the thalamus?

Answer 11

sensory relay nucleus for body

Question 12

What is the role of the ventral posteromedial nucleus of the thalamus?

Answer 12

sensory relay nucleus for the face

Question 13

What is the role of medial geniculate body nucleus of the thalamus?

Answer 13

relay center for auditory stimuli from CN VIII

Question 14

What is the role of the lateral geniculate body nucleus of the thalamus?

Answer 14

thalamic relay for CN II

Question 15

What is the significance of the projections to the thalamus?

Answer 15

specific input goes to the specific area of the cerebral cortex

Question 16

What vessel provides blood supply to the thalamus?

Answer 16

posterior cerebral artery

Question 17

What is thalamic pain syndrome or thalamic syndrome?

Answer 17

occlusions of PCA causing contralateral to lesion symptoms of hemianesthesia, ataxia, excruciating neurogenic pain

Question 18

What is the role of the hypothalamus and what is the significance of damage to this structure?

Answer 18

• regulates endocrine function
• chief effector of limbic system, so if damaged major effects to emotion, memory, and drive related behavior

Question 19

What vessels supply blood to the hypothalamus?

Answer 19

ACA, Ant comm, PCA, Post comm

Question 20

What are the endocrine functions of the hypothalamus?

Answer 20

• body temp regulation
• sleep wake cycle
• emotional and behavioral function

Question 21

What is the effect of diabetes on the hypothalamus?

Answer 21

causes damage to hypothalamus, affecting thirst, hunger, body temp, sleep-wake cycle

Question 22

What is the sub thalamus?

Answer 22

wedge shaped transition between thalamus and midbrain

Question 23

What is significant about the subthalamic nucleus?

Answer 23

nucleus of the subthalamus and basal ganglia

Question 24

What vessel supplies blood to the sub thalamus?

Answer 24

PCA

Question 25

What happens if the subthalamus does not get blood supply?

Answer 25

hemiballismus: involuntary movement of half of the body

Question 26

What basal ganglia nuclei make up the striatum?

Answer 26

caudate and putamen (divided by internal capsule)

Question 27

What basal ganglia nuclei make up the lentiform?

Answer 27

- putamen and globus pallidus

Question 28

How does disinhibition work?

Answer 28

VA and VL nuclei of the thalamus are excitatory, they are tonically inhibited by globus pallidus, in order for the thalamus (VA/VL) to excite the cortex the other basal ganglia must inhibit GP to disinhibit VA and VL in order for movement, must be disinhibition

Question 29

What are the basic concepts of the direct pathway of the basal ganglia?

Answer 29

facilitates movement by disinhibiting VA/VL

Question 30

What is the basic concept of the indirect pathway of the basal ganglia?

Answer 30

decreases movement initiation (involuntary) by inhibiting VA/VL pathway

Question 31

Do the direct and indirect pathway work against each other or in tandem?

Answer 31

truly work together to control movement

Question 32

What is the pathway of the direct pathway?

Answer 32

cerebral cortex > excites striatum > striatum inhibits globus pallidus > thalamus disinhibits > activity facilitated

Question 33

What is the pathway of the indirect pathway?

Answer 33

cerebral cortex > excites striatum > striatum inhibits globus pallidus externus (stops inhibition of subthalamic nucleus) > thalamus inhibited > activity suppressed

Question 34

What is the role of the globus pallidus and subthalamic nucleus in the direct and indirect pathway?

Answer 34

globus pallidus: bouncer, stops thalamus from activating motion subthalamic nucleus: enhances GP ability to inhibit thalamus

Question 35

What is the role of dopamine in movement?

Answer 35

net effect of dopamine is movement effect of loss of dopamine is decreased movement

Question 36

What are the parallel channels?

Answer 36

motor, oculomotor, prefrontal, limbic

Question 37

What is the significance of Parkinson's disease and why does it happen?

Answer 37

- degenerative disease that causes neuron death that causes the loss of dopaminergic projections - loss in dopamine, loss of movement

Question 38

What basal ganglia produces dopamine?

Answer 38

substantia nigra: pigment cells PD patients have no pigment cells

Question 39

What are the cardinal signs of Parkinson's disease?

Answer 39

- Bradykinesia: slow movement initiation - difficulties with balance - rigidity - resting tremor (direct and indirect pathways) - decreased dopamine, limited movement

Question 40

What are the nonmotor impairments of Parkinson's disease?

Answer 40

cognitive decline, autonomic changes, pain, fatigue

Question 41

What is L-DOPA and why is it significant to PT practice?

Answer 41

- dopamine replacement that can cross blood brain barrier - on/off phenomena makes it important that we treat while patient is on an "on" cycle - long term dyskinesia: long term use decreases effectiveness

Question 42

What are some surgical interventions that can be used on patients with PD?

Answer 42

- deep brain stimulation - pallidotomy (removal of GP) - ventrolateral thalamotomy

Question 43

What is Huntington's Disease and its significance?

Answer 43

- inherited neurodegenerative disease - gross atrophy of striatum (caudate and putamen) - loss of GABAergic neurons which decreases inhibition of basal ganglia which causes involuntary movements

Question 44

How is Huntington's Disease characterized?

Answer 44

- motor changes: increase in involuntary movement - cognitive decline leading to dementia - psychiatric disorders

Question 45

What is the medical and physical management of HD?

Answer 45

dopmine antagonists: decrease dopamine, decrease involuntary movement deep brain stimulation removal of globus pallidus internus

Question 46

How would you conduct and exam and intervention for HD?

Answer 46

- united Huntington's disease rating scale - assessment of activities - tests of strength, tone, gait

Question 47

What is hemiballismus and its significance?

Answer 47

- severe form of dyskinesia - wild un-patterned movement of entire extremity - results in under activity of indirect pathway

Question 48

What are the likely causes of OCD and Tourettes?

Answer 48

- problems in both basal ganglia synaptic connectivity and neurotransmission