Hi, I understand the flow of the Direct vs Indirect pathway. I am however, confused as to when exactly the Nigrostriatal Pathway would occur.
I understand that the Direct Pathway is for facilitating wanted moment and vice versa for the indirect pathway, and am able to describe the flow. Im just not understanding the theory as to when the additional pathways commence? Hopefully that makes sense.
Thanks for this question! The nigrostriatal pathway is active whenever the direct and indirect pathways are active. It is only added later in the slides for clarity and to demonstrate the effect of Parkinson’s disease on the direct and indirect pathways because the substantia nigra (and, therefore, dopamine) are introduced in the nigrostriatal pathway.