May 12, 2021 07:00:00

Succeeded in making friends with other individuals with a wireless device embedded in the mouse brain

A research team consisting of engineers and neurobiologists at Northwestern University in the United States will use a 'wireless device embedded in the brain' to stimulate the mouse brain and increase social interaction with other individuals. Succeeded.

Wireless multilateral devices for optogenetic studies of individual and social behaviors | Nature Neuroscience
https://www.nature.com/articles/s41593-021-00849-x

Implanted wireless device triggers mice to form instant bond --Northwestern Now
https://news.northwestern.edu/stories/2021/05/implanted-wireless-device-triggers-mice-to-form-instant-bond/

Scientists remotely controlled the social behavior of mice with light | Science News
https://www.sciencenews.org/article/optogenetics-social-behavior-brains-mice-light

The human brain is a complex system consisting of more than 100 billion neurons (nerve cells) , and it is extremely difficult to select and investigate only specific nerve cells or regions from the outside. A technique called optogenetics, which has been introduced into animals since around 2005, is used to investigate such neural circuit functions in the brain.

Optogenetics is a research field that combines optics and genetic engineering. Researchers first use genetic engineering techniques to express light-activated proteins in specific nerve cells. Next, by shining light on nerve cells that express light-activated proteins, it is possible to control and monitor brain activity.

'This sounds like science fiction, but it's an incredibly useful technique,' said Yevgenia Kozorovitskiy, an associate professor of neurobiologist at Northwestern University. Since it uses genetic engineering techniques, it is not approved to apply optogenetics to humans at the time of writing the article, but it seems that it may be used for the treatment of blindness and paralysis in the future.

Optogenetics is very useful in studying brain activity, but it has limitations due to the fact that it needs to shed light on nerve cells in the brain. Generally, an optical fiber that connects to the brain of a mouse or the like and shines light is connected to an external light source through a wire. In this state, one mouse can be examined, but in an environment where multiple mice interact, each wire is pulled by the movement of the mouse, and it gets entangled or pulled out.

Professor John A. Rogers , a bioelectronics researcher at Northwestern University, said, 'When the mice moved around, the wires were pulled in various ways,' he said. Also pointed out that it will have an effect. If the wire connected to the mouse changes its movement, the mouse movement observed in the experiment may not be realistic.

That's why a research team led by Rogers, a leader in wireless wearable technology, has developed a thin wireless device that can be placed behind the skin and above the skull. The device is only 0.5 mm thick and has a soft thread-like part with an LED light at the tip. It is said that this thread-like part extends into the brain through a small hole made in the skull and irradiates the target nerve cell with light with the LED light at the tip. Wireless devices communicate using the Near Field Communication (NFC) protocol used for electronic payments on smartphones, allowing researchers to control the lighting of LED lights in real time and to supply power wirelessly from surrounding antennas. It seems that he was able to eliminate the heavy and bulky battery.

To see the usefulness of the wireless device we developed, Kozorovitskiy designed an experiment to control social interactions in multiple mice with optogenetics. In fact, when the research team put two mice with devices in a sealed box and synchronized the activation of brain regions related to higher executive function, the frequency and time of social interaction increased. thing. On the other hand, when the activation of the brain region was asynchronous, the social interaction seemed to decrease immediately.

By applying this experiment, it is possible to make more specific pairs interact frequently with more mice gathered in the same place. 'We didn't really think this would work,' commented Kozorovitskiy, who conducted the experiment, and this study is the first direct on the hypothesis that neural synchronization affects social behavior. It was said that it was a typical experimental result.

Rogers, who developed the wireless device, pointed out that this research is the first to realize a battery-free embedded device used for optogenetics and digitally control multiple devices at the same time in a specific environment. 'Although the brain activity of isolated animals is also interesting, studying populations of complex and social interactions across individuals is one of the most important and exciting frontiers in neuroscience. We are now. We have the technology to investigate how bonds between individuals within a population are formed and broken, and how interactions result in a social hierarchy. '