Optogenetics, which expresses a substance called channelrhodopsin that is activated by light in specific cell groups and neural pathways and controls nerve activity by light irradiation, greatly contributes to the elucidation of brain function and is active in research in mice and the like. It is used in.However, there were few successful studies in primates, and only limited studies such as eye movements were reported.

　In order to utilize optogenetics in primates, the researchers first investigated a gene transfer method for efficiently expressing channelrhodopsin in the brain of monkeys.Then, we searched for an adeno-associated virus vector suitable for monkeys, and when the virus vector was administered to the region of the cerebral cortical motor area involved in hand movement, we succeeded in expressing channelrhodopsin in the surrounding neurons.

　In the motor cortex of the cerebral cortex, when a stimulus is applied, a clear movement occurs in a part of the body depending on the location of the stimulus.The researchers irradiated nerve cells expressing channelrhodopsin with light and observed the movement of monkeys caused by light stimulation.As a result, light irradiation efficiently excited nerve cells in the motor cortex and succeeded in causing visually recognizable hand movements.It was also found that this movement was as strong as the movement caused by electrical stimulation.That is, it was confirmed that light stimulation is an effective stimulation method comparable to electrical stimulation that has been used for activating nerve cells for a long time.

　Optogenetics has the advantage that only specific nerve cells can be activated against electrical stimulation that activates all surrounding cells.This achievement opens the door to the utilization of optogenetics in brain research using primates, and is expected to be applied to the treatment of human diseases.

Paper information:[Nature Communications] Forelimb movements evoked by optogenetic stimulation of the macaque motor cortex