We hear a lot about the role of dopamine in mood and behaviour and that's true.

It does play an important role there, but we don't often hear about the role of dopamine in movement.

So, if you need to consciously move or consciously tell a muscle to contract, the motor cortex of your brain needs to ask a deeper area of your brain for permission. This area is called

the basal nuclei. Used to be called the basal ganglia. Now when it asks for permission to move,

the basal nuclei has two responses. It has actually two pathways. One pathway, which is called the

direct pathway, says yes, you can move. But the other pathway called the direct pathway, says, yes, you can move.

But the other pathway called the indirect pathway says, no, you cannot.

Now, this is strange.

You're asking to move a particular muscle, and you're asking for permission, and the basal nuclei

has two simultaneous pathways that says, yes, you can, no, you can't.

That doesn't help us. So we need a way

to figure out how we can move. And this is where dopamine comes into place. So there are dopamine

producing neurons called dopaminergic neurons. They project to this basal nuclei and flood that

area with dopamine when you want to move. What dopamine does is it goes to the direct pathway

and stimulates it, amplifies it, allows the direct pathway to work. So remember the direct

pathway was yes you can move, dopamine facilitates that and says yes you can move. Dopamine

also goes to the indirect pathway which says no no you can't, and inhibits it.

So all you have going at the moment is that direct pathway saying, yeah, you can move.

So the role of dopamine in movement is that allows you to initiate movement, but also by inhibiting or favoring the direct pathway as opposed to the indirect, you don't have

this stop-start, stop-start signal.

So it smooths movement out.

Now think about people with Parkinson's disease.

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