Optogenetics Advances in Monkeys

WIKIMEDIA, J.M. GARGScientists have used optogenetics to target a specific neural pathway in the brain of a macaque monkey and alter the animal’s behavior. As the authors reported in Nature Communications last month, such a feat had been accomplished only in rodents before.

Optogenetics relies on the insertion of a gene for a light-sensitive ion channel. When present in neurons, the channel can turn on or off the activity of a neuron, depending on the flavor of the channel. Previous attempts to use optogenetics in nonhuman primates affected brain regions more generally, rather than particular neural circuits. In this case, Masayuki Matsumoto of Kyoto University and colleagues delivered the channel’s gene specifically to one area of the monkey’s brain called the frontal eye field.

They found that not only did the neurons in this region respond to light shone on the brain, but the monkey’s behavior changed as well. The stimulation caused saccades—quick eye movements. “Our findings clearly demonstrate the causal relationship between the signals transmitted through the ...