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Old 10-12-2015
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Default basal ganglia pathways

Hi can anyone explain the basal ganglia excitation and inhibitory pathways (d1 and d2) i havent come across it in uw. Thanks!
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also in pathoma he says d1 stimulates motion and d2 inhibits the inhibition of motion so both increase motion. However in fa it says d1 increases but d2 decreases motion?
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can u send me ur email? il try sending u some of my notes....lazy to explain them all :P
they r frm najeeb
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IN a nutshell...
normally direct pathway upregulates the motor activity,,indirect pathway downregulates the motor activity..

there are dopamine D1 receptors on direct pathway...so dopamine nigrostrital pathway excites it,, D2 receptors on indircet pathway .....dopamine keeps it inhibites.....
so net effect of dopamine is increased motor activity

In addition there are cholinergic interneurons in corpus striatum that inhibit direct and exite indirect pathway ,,,,opposite to dopamine effect .... so decrease motor activity


in Parkinsons disease dopamine in nigrostriatal pathway is depleted ..so less dopamine decreased motor activity ...thats all my firend
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D1 stimulates the Direct pathway (which normally leads to more movement)

D2 INHIBITS the Indirect pathway (which normally STOPS movement)
- So if you inhibit an inhibitor of movement then you are in effect INCREASING movement

So in Parkinsons, there is no Dopamine so no D1 or D2, therefore less movement overall
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basal ganglia pathways-basal-ganglia-updated.pdf  
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Hey thanks that was very helpful! So do you think we should know all the nuclei (gpe and gpi) to the thalamus, that whole process for the pathways? Its not in uw but i remember i had a question in rx about the exact pathway.
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Quote:
Originally Posted by crunch_time View Post
Hey thanks that was very helpful! So do you think we should know all the nuclei (gpe and gpi) to the thalamus, that whole process for the pathways? Its not in uw but i remember i had a question in rx about the exact pathway.
I tried to break it down to the must know, so i would say at least know what's in that picture

I find sometimes when I dont want to memorize information i just tell myself "ok let me just remember a few facts from this picture today and a few facts tomorrow, until all the picture comes together"

Dont just memorize the picture, talk it out just like i did and try to reason thru it yourself.

I would say that Parkinson pharm is huge, take a look at FA 2014/2015 - they really break down the drugs and why you want to use them

For example:
L-Dopa crosses the BBB easier so the more you stop it from converting into another form of dopamine the more dopamine you will have available to cross the BBB

Good luck!
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This is how i like to think about the nuclei

GPi is an INHIBITOR of movement (bc it inhibits the Thalamus which stimulates movement) and the direct pathway INHIBITS the inhibitor of movement
- So D1 and the Motor cortex (via glutamate) both serve to INHIBIT the inhibitor of movement aka increasing movement

GPexterna normally inhibits the Subthalamic Nucleus, then ask yourself what does the SN do? Well the Subthalamic Nucleus STIMULATES the inhibitor of movement aka the Gpi. That is the indirect pathway

Therefore, D2 will INHIBIT GPexterna. So talk it out. What exactly does that do. D2 will INHIBIT the indirect pathway. The indirect pathway normally INHIBITS movement. So if you inhibit the inhibition of movement, you are in effect INCREASING movement.

Or if you are pissed off and dont feel like memorizing anything just remember that D1 AND D2 BOTH stimulate movement via inhibition of GPi DIRECTLY via D1 or inhibition of GPexterna via D2.

Easy way to memorize it:

Direct pathway - Stimulates movement normally, so all D1 is doing is just stimulating movement

Indirect pathway - INHIBITS movement normally, so all D2 is doing is STOPPING this inhibition, thereby increasing movement. I think of D2 as an INHIBITION of the indirect. SO if you STOP the pathway that is normally used to STOP movement, you are in effect increasing movement.

I know this may seem very confusing, trust me it still confuses me but just try to reason thru the picture. Hope this helped
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FarxFirstAid that was awesome!! Yea i think i gotta just review it over and over till it sticks. I remember that basic part you said but in details gonna take some time to memorize. But thanks again and good luck to you too
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Thumbs Up Basal Ganglia

When I was studying this I watched this youtube video and it helped.
I hope it helps you too.


https://www.youtube.com/watch?v=82oIHBGDoiI
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You are capable of more than you know. Choose a goal that seems right for you and strive to be the best, however hard the path. Persist! the world needs all you can give.
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