ST. HELENA, Calif. — The scientists exchanged one last look and held their breath.

Everything was ready. The electrode was in place, threaded between the two hemispheres of a living cat’s brain; the instruments were tuned to pick up the chatter passing from one half to the other. The only thing left was to listen for that electronic whisper, the brain’s own internal code.

The amplifier hissed — the three scientists expectantly leaning closer — and out it came, loud and clear.

“We all live in a yellow submarine, yellow submarine, yellow submarine ....”

“The Beatles’ song! We somehow picked up the frequency of a radio station,” recalled Michael S. Gazzaniga, chuckling at the 45-year-old memory. “The brain’s secret code. Yeah, right!”

Dr. Gazzaniga, 71, now a professor of psychology at the University of California, Santa Barbara, is best known for a dazzling series of studies that revealed the brain’s split personality, the division of labor between its left and right hemispheres. But he is perhaps next best known for telling stories, many of them about blown experiments, dumb questions and other blunders during his nearly half-century career at the top of his field.