Know the Brain, Use the Brain.

Junichi Ushiba (Full-time Lecturer, Department of Biosciences and Informatics)

In our daily lives, we casually move our legs to walk down a path and extend our hands to grasp a cup. This is made possible by the brain, a mass of 14 billion nerve cells, exchanging signals with each other and commanding the muscles in our limbs to contract in the correct sequence and with the right amount of force. By understanding the mechanisms behind motor expression, we can delve into how brain diseases like stroke and Parkinson's disease cause limb impairment, which will allow us to advance research toward establishing new treatments. To understand and utilize the brain, we analyze brain activity during movement with ourselves as subjects (fig. 1) and virtually construct neural networks within computers and electronic circuits to verify their behavior (fig. 2).

Specifically, for example, we are developing methods to mathematically analyze activity signals from the brain and muscles to accurately identify fine limb tremors that the person may not even be aware of (fig. 3). Results from a large-scale survey of over 100 people have suggested that limb dexterity may depend on an element of "innate brain dexterity." We believe that the analysis methods we have developed and our neuroscientific discoveries can be applied to medicine and sports science, and demonstration experiments are underway at research institutions both inside and outside of Keio.

While we engage in this research to "know the brain," we have also recently begun research to "use the brain"—reading brain states in real time and operating external devices such as computers in response to changes in those states. This technology, which will help people with limb impairments and enrich their lives, is called a Brain-Machine Interface (BMI) and is being actively researched worldwide. The day when you can move a computer mouse cursor just by thinking, or have a robotic hand grasp a cup in place of your own—events that seem like they're straight out of a science fiction novel or movie—is actually just around the corner. Our research team has developed a technology to move a character in the 3D virtual reality world "Second Life" based on the user's motor imagery of their feet or hands (fig. 4). We plan to release an updated version within this year that will allow users to enjoy conversations with other characters and buy clothes they like at shopping malls within the virtual world. This technology, which merges the real and virtual worlds as depicted in the movie "The Matrix," is attracting significant attention both domestically and internationally as a way to support the daily lives of patients with quadriplegia for whom treatment is difficult.

While this technology of reading brain activity to control machines is a blessing for patients with quadriplegia who cannot move their own limbs, it is also true that it challenges our conventional sense of ethics. To what extent is it permissible to know the human brain? To what extent is it permissible to merge the brain with machines? With the rapid advancement of science and technology, we must once again re-examine the question, "What does it mean to be human?"

Advances in life sciences are combining with device engineering, creating a new world while also involving our values and ethics. We are now in an era where advanced neuroscience requires not only high-level specialized skills but also broad, comprehensive abilities. Why not take on the challenge of this new trend, where traditional academic fields such as science, engineering, medical sciences, and ethics are merging in a multilayered fashion?

The Tomita-Ushiba Laboratory has established a collaborative system with the Keio University Tsukigase Rehabilitation Center, the School of Medicine's Department of Rehabilitation Medicine, and its Department of Rehabilitation to promote practice-oriented, collaborative medical-engineering education and research.