Everybody makes mistakes--the key to success is figuring out how to recover from them. A rare opportunity not only to record from single human brain cells, but also to study the effects of their loss suggests that a certain brain area may be important for our ability to form effective strategies, according to a study in the December issue of Nature Neuroscience.
For some patients suffering from severe depression or obsessive compulsive disorder that cannot be eased by other therapies, surgical removal of a brain area called the dorsal anterior cingulate can be a last resort. To find the area they need to target, surgeons routinely insert probes to record electrical signals from brain cells. Five patients who underwent this surgery at Harvard gave informed consent for researchers to record these electrical signals from their brains before the operation.
Emad Eskandar and colleagues recorded output from dorsal anterior cingulate cells in these patients as they played a simple computer game, while on the operating table. The patients were asked to perform a simple movement task for a small reward under shifting reward conditions. The patients saw a series of symbols on the computer screen, and received a small sum of virtual money for moving a joystick in the right direction in response to each symbol. Usually they would have to repeat the action, but occasionally they were asked to switch the direction of the joystick, and in some cases received a smaller amount of money for doing so. The patients' brain cells were most active during this turn of events, as if to signal that the outcome would be worse than expected. Because the therapeutic surgery removed the brain area containing these cells, the authors were able to confirm their importance for strategic behavior. The patients played the game again immediately after the surgery, and made more mistakes when they had to switch behavior for a lower reward. This study provides a rare window onto the link between brain function and a human behavior, showing the contribution that a single brain area can make to something as complex as strategy formation.
'Conducted with appropriate care and precaution, studies like this one will be critical in supplementing the more widely available non-invasive tools of cognitive neuroscience' say William Gehring and Stephan Taylor in an accompanying News and Views article.
Emad Eskandar (Harvard Medical School, Boston, MA, USA)
Tel: +1 617432 2805, E-mail: firstname.lastname@example.org
Additional contact for comment on paper:
William Gehring (University of Michigan, Ann Arbor, MI, USA)
Tel: +1 734 763 4381, E-mail: email@example.com
Also available online.
(C) Nature Neuroscience press release.
Message posted by: Trevor M. D'Souza