Brain keeps eye on performance.

Comedic-movie spy Austin Powers blurts out, "Oh, behave," to evil wrongdoers and, "Yeah, baby," when justice and Beatles-era fashions prevail. A brain area known to control shifts in eye gaze similarly registers an "Oh, behave" response after errors in a visual task and a "Yeah, baby" reaction after successes--at least in monkeys--a new study finds.

This frontal-brain region, called the supplementary eye field, lies within a larger neural system devoted to regulating one's behavior, proposes a team led by psychologist Jeffrey D. Schall of Vanderbilt University in Nashville.

Schall and his colleagues trained two monkeys to stare at a spot in the center of a computer screen and then shift their gaze to a spot that appeared elsewhere when the central spot vanished. On some trials, the central spot reappeared quickly, signaling the monkeys to cancel the shift in gaze.

Electrodes implanted in the animals' supplementary eye fields identified a group of cells that became more active only after monkeys failed to stop the gaze shift and another that reacted solely to successful cancellations, the scientists report in the Dec. 14 NATURE. A third set of neurons boosted its activity when the monkeys received juice as a reward for correct responses. Now, that's shagadelic.