Origin of Consciousness -- Neural Networks in Brain

Why are we conscious? This is another BIG question. Perhaps the most challenging one among all scientific questions. At least we know that consciousness is somehow resulted from neural activities deep in our brain. Can we eventually understand the true origin of consciousness by physics laws? Or not?


The two pictures above show the large scale structure of the Universe (by computer simulation) on one side, and the actual image of a rat’s brain (by Ca imaging) on the other side. Which is which? They are remarkably alike; the universe consists of ~100 billion galaxies while the human brain consists of ~100 billion neurons. So we have the total universe in our brain. To be exact, our brain is far more complex than the universe because each neuron has ~100 connections to its nearby neurons, making 10 trillion connections as a whole. Not only that, they are dynamically communicating to each other every mili second. (By the way, the left is a rat's brain, the right is the universe.)


Our brain has emerged as a result of fierce survival games on the earth over the last 4 billion years of life's evolutional process. Whoever had better predictive power than others, by a superior brain, he or she won in the game. Thanks to this process of
survival of the fittest, we are here today. The above pictures illustrate the evolution of the brains from a paramecium (no brain) to a rat (100 million neurons, i.e. 0.1% of neurons in our brain). How could it eventually evolve into a human brain? Can we find physics laws beyond the Darwinism?

Some Examples of Symmetry Breaking

Having 100 billion neurons and 10 trillion connections are not enough to be a human. At the earliest stage of infant's brain, neurons are going to establish their specific connections, following genetic information based on epigenetics as shown the figure below. At the same time (and more importantly a later time), neural networks become more complex and sophisticated, taking various sensory inputs and experiences. This process is arguably the most complex breaking of symmetry in nature.


At Arisaka Lab, we are trying to investigate the mechanism of symmetry breaking of neural networks too, taking an advantage of the advanced photon detectors and high-speed optical microscopes such as two photon excitation.

Researches at Arisaka Lab

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