New York Times: A brain implant that fine-tunes communication among neurons has been successfully tested in primates for the first time. In a paper published yesterday in the Journal of Neural Engineering, Theodore Berger of the University of Southern California and colleagues describe their experiment involving five rhesus monkeys. The researchers trained the monkeys to play a picture-matching game. Then they implanted a probe with two sensors in the monkeys’ cerebral cortex and studied the firing of neurons as the animals made their choices. After having determined the correct signal for a particular choice, the researchers were able to relay that signal into the monkeys’ brains while they were in the process of choosing and thus improve the chances the monkeys would make the right decision. Although the current study is limited to just one circuit in the brain—decision making actually involves multiple neural circuits—the technology could one day lead to an implantable chip that could help people who have suffered brain damage.