Nsp: Basal Ganglia

Front 1

What makes up the dorsal basal ganglia?

Back 1

caudate nucleus
putamen
globus pallidus

Front 2

What makes up the ventral basal ganglia?

Back 2

nucleus accumbens
olfactor tubercle

Front 3

What artery profuses the putamen, globus pallidus, and internal capsule?

Back 3

lenticulostriate branches of MI of MCA

Front 4

What supplies mainly the caudate?

Back 4

medial striate artery (ACA)

Front 5

What supplies the thalamic and mesencephalic regions of the basal ganglia?

Back 5

thalamoperforating arteries, posterior choroidal, and thalmogeniculate arteries

(branches of P1 segment of PCA and branches of the posterior communicating artery)

Front 6

Which parts of the cerebral cortex do not have projections to the basal ganglia?

Back 6

the primary visual cortex and the primary auditory cortex

Front 7

Describe the pathway of the sensorimotor region of the basal ganglia?

Back 7

Sensorimotor regions of cerebral cortex >
putamen >
posterior globus pallidus >
VA & VLa thalamic nuclei

Front 8

Describe the prefrontal pathway of the basal ganglia

Back 8

prefrontal region of the cerebral cortex>
anterior caudate>
lateral dorsalmedial globus pallidus >
DM and VA thalamic nuclei

Front 9

Describe the oculomotor pathway of the basal ganglia?

Back 9

frontal eye field >
body of caudate>
dorsomedial globus pallidus>
DM and VA thalamic nuclei

Front 10

Describe the limbic pathway of the basal ganglia?

Back 10

Limbic regions of cortex, the amygdala, and hippocampus >
ventral striatum>
ventral pallidum>
DM thalamic nucleus

Front 11

What are the major functions of the basal ganglia?

Back 11

1. Facilitation of desired movements and suppression of movements that interfere with the desired movements
2. Initiation and cessation of movements
3. Sequencing of movement
4. Scaling of movements
5. Adjusting motor set (posture)
6. Indirectly affects movement
7. Other systems (eye movements-oculomotor, thought processes-prefrontal, emotional responses-limbic)

Front 12

What are the projection neurons in the neostriatum called and what neurotransmitter do they contain?

Back 12

medium spiny neurons, GABA (95%)


the remaining neurons are larger, cholinergic, inhibitory, and tonically active

Front 13

What are the major projections of the neostriatum (caudate and putamen)? (2)

Back 13

1. both divisions of the globus pallidus (striatopallidal fibers)
2. substantia nigra (striatonigral fibers)

Front 14

What is the major source of input to the neostriatum?

Back 14

1. cerebral cortex (corticostriatal fibers)
2. substantia nigra pars compacta (nigrostriatal fibers)

Front 15

Where do the external (lateral) globus pallidus project to?

Back 15

subthalmic nucleus (pallidosubthalmic fibers)

Front 16

Where does the internal (medial) globus pallidus project to?

Back 16

VA
VLa thalamic nuclei

This provides the MAJOR output of basal ganglia circuit

Front 17

What are the major sources of input to the globus pallidus? (2)

Back 17

1. neostriatum (caudate & putamen)
2. subthalamic nucleus

Front 18

Where does the Substantia Nigra pars Reticulata project to?

Back 18

VA and VLa

It's major source of input is the neostriatum and subthalamic nucleus

Front 19

Where does the Substantia Nigra pars compacta project to?

Back 19

primarily the neostratium (nigrostriatal fibers)

This pathway is dopaminergic

Front 20

What are the major projections of the Subthalamic nucleus?

Back 20

internal globus pallidus and reticulated substantia nigra

Front 21

What is the major input to the Subthalamic nucleus

Back 21

external globus pallidus

Front 22

Although the Pedunculopontine Nucleus contains a high concentration of cholinergic neurons, this type of neuron are the primary ones that interconnect w/ the basal ganglia

Back 22

glutaminergic neurons

Front 23

What projections allow the PPn to participate in postural functions and control of walking that the basal ganglia mediates

Back 23

projections to the motor regions of the reticular formation and to the spinal cord

Front 24

Where does the superior colliculus recieve input from

Back 24

the reticulated substantia nigra

it also influences eye movements that the basal ganglia produce

Front 25

Fill in the blank:

The Globus Pallidus has tonic activity which produces ___________ in its target projections.

New activity in the neostriatum (putamen) ___________ globus pallidus, producing _______________ of target projections of the globus pallidus

Back 25

The Globus Pallidus has tonic activity which produces INHIBITION in its target projections.

New activity in the neostriatum INHIBITS globus pallidus, producing DISINHIBITION of target projections of the globus pallidus (thalamus)

Front 26

At rest, there is _______ activity in the putamen.

At rest, there is ______ activity in the globus pallidus and substantia nigra, pars reticulata (GABA) - this inhibits the thalamus

Back 26

At rest, there is LITTLE activity in the putamen.

At rest, there is A LOT OF activity in the globus pallidus and substantia nigra, pars reticulata (GABA) - this inhibits the thalamus at rest.

With a command to move, the cortex activates the putamen (via Glutamate). The putamen then inhibits the pallidothalamic and nigrothalmic neurons via GABA.

The end result is disinhibition of the thalamus

Front 27

What is the sequence/circuitry of the indirect pathway of the basal ganglia starting with the Putamen?

Back 27

Putamen* (GABA and enkephalin)-->
[Globus Pallidus (lateral) (GABA)--I
Subthalamic nucleus (glutamate)-->]
Globus pallidus (medial) & substantia nigra, pars reticulata (GABA) --I
Thalamus (glutamate)

Front 28

What is the end result of the direct pathway?

of the indirect pathway?

Back 28

the direct pathway disinhibits the thalamus, thereby increasing thalamocortical activity

the indirect pathway excites pallidothalamic neurons which inhibit the thalamus, thereby decreasing thalamocortical activity

Front 29

What is the difference of Dopamine from the substantia nigra on Striatopallidal neurons projecting to the medial vs. the lateral globus pallidus

Back 29

medial globus pallidus- Excitates (via D1) (direct)

lateral globus pallidus - inhibits (via D2) indirect pathway

Front 30

What disease is characterized by a kinesia and bradykinesia, resting tremor (3-6 Hz), and plastic, or lead pipe rigidity

Back 30

Parkinson Disease

What causes this?

Hint 30

loss of dopaminergic neurons in the nigrostriatal pathway

Front 31

What do you often give with L-DOPA to increase its availability to the brain?

Back 31

carbidopa (an inhibitor of dopa decarboxylase)

Front 32

L-DOPA is contraindicated in who?

Back 32

psychotic patients
closed-angle glaucoma

it should be given w/ carbidopa in pts w/ CV disease

Care should be taken when giving it to pts w/ peptic ulcers or history of melanoma

Front 33

A D2 receptor agonist which inhibits the activity of the indirect pathway

Back 33

bromocriptine

not commonly used anymore

Front 34

Excites D3 receptors

Excites D2 Receptors

both are used to decrease the dose needed of L-DOPA

Back 34

D3- Pramipexole

D2-Ropinirole

Who are they contraindicated in?

Hint 34

pts w/ psychosis
recent MI
peptic ulcers

Front 35

What is the difference between MAO-A and MAO-B?

Back 35

MAO-A metabolizes NE, DA, 5HT

MAO-B metabolizes only DA

Front 36

Which drugs block MAO-B to increase the level of dopamine?

Back 36

Selegiline and Rasagiline

What are the contraindications for these drugs?

Hint 36

Pts taking meperidine

Should not give w/ pts taking non-selective MAO inhibitors b/c of possibility of hypertensive crisis

Front 37

What is COMT?

Back 37

Catechol-O-methyltransferase- metabolizes monoamines & its activity increases w/ blockade of dopa decarboxylase w/ a resultant increase in L-DOPA metabolism

COMT Inhibitors reduce this response. What drugs do this?

Hint 37

Tolcapone and entacapone

Stalevo is a combo of LDOPA, carbidopa, and entacapone

**tolcapone may cause liver failure**

Front 38

Which drug is used for the temporary relief of the off phenomenon?

Back 38

Apomorphine

What is one major side effect and how can you treat it?

Hint 38

nausea

Trimethobenzamide (anti-emetic)

Front 39

What antiviral drug has been shown to help Parkinsonians for a few weeks?

Back 39

Amantadine

Which patients should this be used in caution in?

Hint 39

pts w/ seizures or heart failure

Front 40

What are antimuscarinic drugs most effective in treating w/ regards to Parkinson dz?

Back 40

tremor and rigidity>>>>>> bradykinesia

What are examples of these drugs?

Hint 40

Benztropine, Biperiden

(orphenadrine, procyclidine, trihexyphenidryl)

Front 41

What drugs worsen Parkinson disease?

Back 41

Dopamine antagonists and cholinergic agonists

Front 42

What is described as rapid, jerky, alternating movements of trunk, head, face and limbs superimposed on HYPOTONIC background of motor activity?

Back 42

chorea (dance-like movement)

Front 43

What is described as slow-writhing, ceaseless movements superimposed on HYPERTONIC motor background activity?

Back 43

Athetosis

What body part does this usually affect?

Hint 43

the hands
(less often the lips, tongue, neck, and foot)


Note: a pt can have athetosis and chorea

Front 44

What is described as violent flinging motions of the limbs?

Back 44

Ballism
Often described as extreme chorea

Front 45

What is described as rapid, stereotyped, coordinated, repetitve movements that may ease w/ voluntary movement and becomes worse w/ stress?

Back 45

Tics

What is an example of a Tic disorder characterized by complex vocal sounds including obscentities

Hint 45

Tourette's Syndrome

Front 46

In early stages of Huntington disease, there is a loss of what?

Back 46

GABA/enkephalin striatopallidal neurons projecting to the lateral globus pallidus.

This ultimately causes ENHANCED THALAMOCORTICAL ACTIVITY

Front 47

What drugs can you give to a Huntington pt to reduce abnormal movements?

Back 47

Dopamine (D2) receptor antagonist

(DA agonists enhance movements)

Hint 47

You can also give antipsychotic drugs that block DA receptors such as Haloperidol, perphenazine, and olanzapine

Front 48

What drugs deplete central DA by preventing storage and is used to treat Huntington dz?

Back 48

Reserpine and Tetrabenazine

The sympatholytic effects can be serious, and limit the utility of these drugs

Front 49

What causes Ballism?

Back 49

Damage to the subthalamic nuclei (reducing the excitatory drive to the medial globus pallidus)

This ultimately ENHANCES THALAMOCORTICAL ACTIVITY