Tuesday, 4-26-Basal Ganglia (Karius)

Question 1

The __ receives the inputs to the basal ganglia

Answer 1

Striatum

Question 2

What is the path of the nigrostriatal dopaminergic system?

Answer 2

From: Substantia nigra pars compacta
To: nuclei of striatum

Effects: D1 receptors (+) ; D2 receptors (-)

Question 3

What are the effects of the intrastriatal cholinergic system?

Answer 3

Excitatory

Question 4

This is the “Direct pathway” that leads to initiation of movement:

Answer 4

Striatonigral GABA-ergic pathway

From striatum to the SNPR and GPi

Question 5

What are the components of the substantia nigra?

Answer 5

Pars compacta and reticulata

Question 6

Where are the cell bodies of dopaminergic neurons located? Where do their axons travel?

Answer 6

Cell bodies: SNPC
Axons travel to the striatum

D1 and D2 receptors on different neurons in the striatum

Question 7

Where are cholinergic cell bodies found? Where do their axons synapse? What is its role?

Answer 7

Cell bodies: neurons of striatum
Axons: synapse on other neurons in striatum
Excitation

Question 8

Where are GABA-ergic cell bodies located? Where do their axons travel? What is its role?

Answer 8

Cell bodies: Striatum
Axons travel to GP internal segment and SNPR
Inhibition

Question 9

What are the major inputs to the striatum?

What are the major outputs of the striatum?

Answer 9

Substantia nigra pars compacts receives inputs and relays them to the striatum

GP (internal segment) and SNPR send axons to thalamus. When activated, they release GABA at synapses in the thalamus and cause inhibition

Question 10

The pars compact of substantia nigra releases this NT on the striatum:

The primary motor cortex, SMC, and premotor cortex release this NT on the striatum:

Answer 10

Dopamine

EAA

Question 11

The effect of dopamine released in the striatum indicates that there are 2 distinct pathways within the basal ganglia that control motion:

Describe the direct pathway: ___

Describe the indirect pathway: ___

Answer 11

Direct: D1 receptors, excited by dopamine, allows motion

Indirect: D2 receptors, inhibited by dopamine, excited by EAA/Ach, inhibits motion

Question 12

In the “direct pathway”, SNPC dopaminergic inputs excite the striatal cells. The striatal cells then release __ in the SNPR and GPi. By inhibiting the SNPR and GPi, __ is released in the thalamus. The thalamus is then free to excite the cortex, allowing the initiation of movement

Answer 12

MORE GABA

LESS GABA

Question 13

When the indirect pathway is active, what is the result?

Answer 13

Inhibit motion

Question 14

In parkinson’s disease, the ___ input is abolished

Answer 14

SNPC

Question 15

In parkinsons disease, the SNPC is abolished and has these 2 affects:

Answer 15

1) Direct pathway becomes difficult to activate
2) Indirect pathway becomes overactive (due to loss of inhibition)

We see an inability to initiate motion

Question 16

The function of __ is planning of complex motor actions and carrying out of “thought” processes

Answer 16

Association cortex

Question 17

The __ planns complex motor actions and interacts with the PTO association area and all levels of motor cortex

Answer 17

Prefrontal cx

Question 18

Planning of a complex motor act requires these areas:

Answer 18

Frontal association area
Supplementary motor cx
Premotor cx
Cerebrocerebellum

Question 19

Once motion is planned, sequenced, and “approved”, the appropriate columns in the __ are activated. AP’s then travel down the axons of the pyramidal (Betz) cells and activate the ___ that innervate the muscles needed to complete the motion. Once the motion has started, the ___ is called upon to make sure the motion is correct

Answer 19

Primary motor cx

Alpha-motor neurons

Spinocerebellum

Question 20

What are the components of the Striatum?

Answer 20

Putamen and caudate nucleus