Professor Yagi applies objective approaches to explore the subjective world of the mind. How are our brains composed, and how do we become conscious beings? Professor Yagi hopes to use biology to make sense of these puzzles.
The complexity of nerve cell connections
Composed of anything from one hundred billion to several hundred billion neurons, brain process almost infinite volumes of information. We understand that these cells form groups, and that at times, the activities of these groups generate memories and information. It is also known that the same cells are often used by different groups. The numerous combinations yielded by these different groupings are thought to enable information processing on a virtually infinite scale.
Why do neuronal cells each have distinct individual qualities, and how can they form part of so many different groups? The probability that adjacent cells will form a circuit is one in five, meaning that even cells in close proximity may not necessarily be connected. Recent analysis has revealed that the cells have both the capacity to connect in accordance with set rules, and the capacity to connect accidentally. Neural circuits are imbued with this kind of complexity.
We do not yet understand how these properties of regularity and fortuity co-exist to form networks, but I believe that the genetic research we are currently pursuing will help us to unravel the mysteries of circuit formation.
The 50 genes that determine neural cell affinity
We have discovered that there are around 50 types of genes that, when they produce proteins, determine affinity between different neural cells. These 50 types manifest randomly in numerous combinations. Cells with the same affinity generated under these conditions connect with each other in a regular manner. In other words, neural circuits are formed through a combination of regularity and randomness. We are now seeking to prove that it is this kind of network complexity that provides the basis for what we know as the human “mind”.
Interdisciplinary research is not a goal, but an approach that brings us closer to essential truths
We are not the only ones seeking to understand the mind and consciousness through genetics and generation programs. There are researchers exploring the same theme from the standpoints of engineering and physiology. I think that if researchers with the same essential goal each think seriously about their own work, interdisciplinary connections will be made naturally. In this sense, interdisciplinary research should not be treated a starting point; instead, it is something that emerges as essential in order to generate the outputs anticipated.
Personally, I hope to make sense of problems of the mind through genetic information, but as my research progresses, more connections emerge with physiology, mathematics, and engineering. This is a chance to have our ideas understood by experts in other fields, and to work together with them. The closer we get to the root of the problem, the more essential interdisciplinary research becomes.
A message to students interested in interdisciplinary research
I want students to apply themselves fully to topics that interest them and that they think are essential. Pursuing such challenges is never a waste of time: on the contrary, it will help you find connections between things that you believed to be unrelated or irrelevant. It can also yield opportunities to create something truly novel.