Basal Ganglia

Question 1

What are the two components of the striatum?

Answer 1

Caudate and putamen

Question 2

What are the structures within the lenticular nucleus?

Answer 2

putamen

globus pallidus

Question 3

what are the efferent nuclei of the basal ganglia?

Answer 3

globus pallidus and pars reticulata of substantia nigra

Question 4

What are the three nuclei of the basal ganglia proper?

Answer 4

1. caudate
2. putamen
3. globus pallidus

Question 5

Do the putamen and GP have similar functions?

Answer 5

No

Question 6

the striatum recieves inputs from all areas of cortex except the (blank) pathways (2)

Answer 6

primary visual

primary auditory

Question 7

The caudate follows the path of what structure?

Answer 7

lateral ventricle

Question 8

The direct pathway (inc/dec) excitatory thalamic input to cortex?

Answer 8

INCREASES

Question 9

The direct pathway turns (up/down) motor activity

Answer 9

UP

Question 10

Under normal circumstances, list whether each neuron has excitatory or inhibitory actions in the direct pathway:

1. cortex to striatum
2. striatum to GPi
3. GPi to VA/VL of thalamus
4. VA/VL of thalamus to motor cortex
5. Motor cortex to lower motor neurons

Answer 10

1. e
2. i
3. i
4. e
5. e

Question 11

Under normal circumstances when the cortex is sending info through the direct pathway, is the VA/VL activated or inhibited?

Answer 11

Activated

Question 12

what neurotransmitter is used in inhibitory signaling?

Answer 12

GABA

Question 13

What neurotransmitter is used in excitatory signaling?

Answer 13

Glutamate

Question 14

Without pathway stimulation, is the VA/VL tonically active or inhibited?

Answer 14

Tonically inhibited; it requires the input from the cortex down the pathway to inhibit the inhibitor to allow signaling

Question 15

the indirect pathway (inc./dec.) excitatory thalamic input to cortex

Answer 15

DECREASES

Question 16

the indirect pathway turns (up/down) motor activity

Answer 16

turns down

Question 17

Under normal circumstances, list whether each neuron has excitatory or inhibitory actions in the indirect pathway:

1. cortex to striatum
2. striatum to GPe
3. GPe to subthalamic
4. Subthalamic to GPi
5. GPi to VA/VL
6. VA/VL to motor cortex
7. Motor cortex to LMN

Answer 17

1. e
2. i
3. i
4. e
5. i
6. e
7. e

Question 18

What are the two components of the substantia nigra?

Answer 18

pars reticulata

pars compacta

Question 19

what neurotransmitter does the substantia nigra release? what system is it involved in
/

Answer 19

dopamine

reward

Question 20

D1 receptors are found on the (direct/indirect) pathway

Answer 20

direct

Question 21

D2 receptors are found on the (direct/indirect) pathway

Answer 21

indirect

Question 22

Are D1 receptors excitatory or inhibitory? what is there effect on cAMP?

Answer 22

excitatory, stimulates cAMP

Question 23

are D2 receptors excitatory or inhibitory? What is there effect on cAMP?

Answer 23

inhibitory, inhibits cAMP

Question 24

what is the overall effect of dopamine release by the sub. nigra?

Answer 24

increase motor activity

Question 25

Does the sub. nigra turn up or down the direct pathway? the indirect pathway?

Answer 25

turns UP direct | turns DOWN indirect

Question 26

Does the sub. nigra inc or dec the drive to the VA/VL of the thalamus?

Answer 26

INCREASE

Question 27

Where are the small cholinergic cells located?

Answer 27

in the striatum

Question 28

Do the cholinergic neurons act on both the direct and inhibitory paths?

Answer 28

yes!

Question 29

Do the striatal neurons turn up or turn down motor activity

Answer 29

turn down

Question 30

What is the effect of the striatal interneurons (cholinergic) on the direct pathway? on the indirect? on the VA/VL drive to the cortex?

Answer 30

turns down the direct pathway turns up the indirect pathway decreases drive to the cortex

Question 31

What are the symptoms of Parkinson's disease?

Answer 31

``` hypokinetism rest tremor masked facies rigidity (cogwheel) retropulsion festinating gait shuffling gait loss of postural reflexes depression, anxiety, and dementia ```

Question 32

Parkinson's causes a loss of cells in what nucleus, leading to low levels of what neurotransmitter?

Answer 32

Substantia nigra, dopamine

Question 33

Does Parkinson's primarily affect the direct or indirect pathway?

Answer 33

direct

Question 34

Describe the effects of Parkinson's on the direct pathway

Answer 34

Decreased dopamine, less stimulation from sub. nigra to striatum, which leads to less "inhibiting the inhibitor", so the VA/VL remains tonically inactivated

Question 35

What is the effect of losing the D2 receptors in Parkinson's?

Answer 35

Less inhibition of the indirect pathway

Question 36

Hemiballismus results from a (contra/ipsi)lateral lesion of the subthalamic nucleus?

Answer 36

contralateral

Question 37

Destruction of the subthalamic nuclei breaks the indirect pathway, thus (inc./dec.) motor activity

Answer 37

increasing

Question 38

Specifically, destruction of the subthalamic nuclei breaks the indirect chain how?

Answer 38

There are no excitatory neurons heading towards the GPi to stimulate the direct inhibitor of the VA/VL

Question 39

What are the characteristics of Huntington's disease

Answer 39

Starts in 40s to 50s starts as movement disorder, progresses to dementia and death rapid jerky, dance-like motions

Question 40

Huntington's disease is caused by the loss of what basal ganglia?

Answer 40

the striatum, specifically the ACh neurons

Question 41

What are the overall effects of HD on the direct and indirect pathways?

Answer 41

Increase the direct | decrease the indirect

Question 42

What is the mechanism that causes the increase in direct pathway and decrease in the indirect path in HD?

Answer 42

Loss of ACh cells; no ACh in pathway 1 means Dopamine is unapposed, so more action. Loss of ACh in pathway 2 means there is no inhibition.

Question 43

In lower motor neuron syndrome, explain your muscle control, tone, reflexes, and the side of the spinal cord that caused the problem

Answer 43

1. paralysis 2. atrophy 3. areflexia 4. ipsi deficit in cord

Question 44

In Upper motor neuron syndrome, explain your muscle control, tone, reflexes, and the side of the spinal cord that caused the problem

Answer 44

1. paresis (weakness) 2. no atrophy 3. hyperreflexia, hypertonia and SPASTICITY 4. CONTRA deficit above decussation; IPSI below

Question 45

In lesions of the basal ganglia, explain your muscle control, tone, reflexes, and the side of the spinal cord that caused the problem

Answer 45

1. no paralysis 2. no atrophy 3. Parkinson's: rigidity, resting tremor, bradykinesia 3b. Hungtington's: chorea, hyperkinesia 4. Contralateral

Question 46

In upper motor neuron syndrome, loss of tonic inhibition to (blank) fibers causes the spindles to have stronger contractions leading to hyperreflexia

Answer 46

gamma

Question 47

Killing upper motor neurons leads to a loss of (phasic/graduated) activity of alpha motor neurons and loss of tonic (inhibition/activation) of gamma fibers

Answer 47

phasic, inhibition

Question 48

UMN paralysis or weakness is due to the (blank) nerve fiber

Answer 48

alpha

Question 49

UMN spasticity and hyperreflexia are due to (blank) nerve fibers

Answer 49

gamma

Question 50

T/F: Parkinson's patients have NORMAL deep tendon reflexes

Answer 50

yessiree bob!