Under the heading of "Its a funny old game"....

At times I play bass pedals. If I hit a complete mental block when playing a tune from memory, to such an extent that i have to stop playing with my hands, I continue playing the correct bass with my feet even though I am not remembering the chord structure. Then my brain resets, I remember where i am in the tune and carry on at the right place.

My drummer colleague reckons it's something to do with muscle memory. He says he knows I'm going to go blank about 10 seconds beforehand because my playing sounds less relaxed than usual!