[biggieshellz]

Part of it was from listening to his own recordings, part of it was from discovering it inside his brain again. As Pat's aneurysm grew over time, it's likely that his brain had already somewhat remodeled to accommodate it. IIRC, in a TV show about it, they talked with one of his friends/students whom he would play guitar duos with. His friend was playing for Pat after the aneurysm (Pat wasn't back to playing yet) and the guy hit a wrong chord and Pat suddenly said "No, D minor 9th" and grabbed the guitar and played the right chord.

Pat also tells a similar story about meeting Joe Pesci backstage and knowing him only from movies until Joe tells him, "I can tell you what you used to drink at Smalls' Paradise in the '60s". Video here: https://www.youtube.com/watch?v=niUwDegpYyo