The research groups of the Quantum Science and Technology Research and Development Organization, the Primate Research Institute of Kyoto University, and the National Institute of Mental Health have established the world's first technology for imaging artificial receptors expressed in the monkey brain in the living body. We succeeded in changing the value-judging behavior by systemically administering a drug that acts on the artificial receptor to monkeys that confirmed that the artificial receptor was expressed in the target brain region.
The brain has many parts called "nuclei", which consist of a group of nerve cells responsible for a specific function.The collaboration of these parts produces higher brain functions such as judgment and decision making.When this mechanism breaks down, it indicates pathological conditions such as psychiatric and neurological disorders, so it was necessary to identify functions that change by manipulating the neural activity of specific brain regions.
This time, the research group infected a neural cell population in a specific brain region of monkeys with a viral vector incorporating an artificial receptor gene.The expressed artificial receptor was imaged by PET (positron emission tomography), and the timing, position, range, and intensity of expression were successfully evaluated alive.Furthermore, we decided to express artificial receptors in a group of nerve cells in a part of the structure called the striatum, and systemically administer drugs that act on the receptors to "switch off" nerve activity.Until then, monkeys had been trained in behavior based on "value judgment" (= motivation) based on the amount of reward received, but disorders were observed after administration of this drug.From this, it was confirmed that this striatal area is responsible for the value judgment.
The results of this research are expected to make dramatic progress in higher brain function research using monkeys.In addition, it is expected to develop an epoch-making treatment method such as introducing an artificial receptor gene into a group of nerve cells that cause mental and neurological diseases and suppressing it with a drug only when symptoms appear.
