MC-22 schematic question

Hi folks,

I have a question about this schematic and I'm sure one of you could answer it. I placed a yellow arrow pointing at what appears to be some sort of shielded connection? To the left there is a center tapped potentiometer. On the wiper connection that goes to the grid of V4-A, there is a circle around the wire that actually connects to the cathode. What is that? Maybe some sort of shielded wire connecting wiper to grid and the "ground" of the cable goes to the cathode?

Thanks for your help,

Tim
p.s. I hope I actually attached the schematic photo. If not I will try to fix...
 

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