Using a technique that makes it possible to control the activity of specific engineered neurons with light, neuroscientists have modified behaviour in primates.

Optogenetics can help researchers to figure out the role of individual neurons, but it has previously been used to control behaviour only in rodents and invertebrates. Wim Vanduffel at Harvard Medical School in Boston, Massachusetts, and his colleagues genetically modified neurons in the premotor and prefrontal cortex brain regions of two rhesus monkeys, so that the neurons fired when blue light was delivered into the brain by an optical cable. Stimulating these neurons as the monkeys performed an eye-movement task changed the latencies of eye movements in both animals. Functional magnetic resonance imaging revealed that the stimulation induced distinct patterns of brain activity during the task.

Curr. Biol. http://dx.doi.org/10.1016/j.cub.2012.07.023 (2012)