Research on Brain States and Transitions
Human brain is one of nature’s most complex systems, and studying the brain leads to new insights and methods applicable beyond neuroscience. Our research focuses on the dynamics and state transitions of the human brain, motivated by the idea that understanding information flow and processing in the brain is key to identifying, monitoring, and ultimately controlling brain state transitions. Our research combines analytical modeling and simulations with multi-modal recordings of neural dynamics (EEG, ECoG, fMRI) during real-world cognitive functions.
Conscious vs. Unconscious States
For example, possibly two states which are most different from each other is conscious and unconscious states. When we are conscious we can hear, understand and have thoughts; when we’re unconscious, we cannot; now, the underlying brain anatomy is the same across those two states, but the dynamics are very different. So, there must be some foam of a functional state change happening, and understanding such changes in state is the key motivation of our research. We want to know how these changes arise, how they are controlled in the brain, and how we can influence them.
Our experiments and models have shown that there exists a robust yet very dynamic information flow pattern during the conscious state, whereas the pattern becomes very random during the unconscious state. Now, what do these patterns mean and what does the difference of the patterns between states mean?
Internal vs. External Modes
Our brain states reflect distinct patterns of information flow from moment to moment. Our models (e.g., coupled oscillator systems) and simulations predict mixtures of externally biased mode where we are more focused on external world (dominant bottom-up flow: information flowing from sensory to higher order areas), and internally biased mode where we are internalizing the information from the world (dominant top-down flow: information flowing from higher order to sensory areas). The predictions match the pattern changes observed in the experimental data.
In addition to extending our previous research, we ask: i) By switching between internal and external modes, how does the brain facilitate to perceive, memorize and learn the information from the world? ii) With experiments involving various stimuli, how can we stimulate and control brain mode transitions? Ultimately, we aim to provide general principles of the information flow dynamics and state transitions of the brain.