Super-Network Brain Physiology
Every scientific endeavor begins with observation. However, observation alone can only lead to a realization of correlation. Experimentation is required to understand the observed causal relationships. The brain is a complex multicellular organ. The human "mind" is likely created by communication between brain cells. This notion is derived from studies of correlation between cell activity and animal behavior. Recently, tools were developed that give scientists specific control of cell activity. For example, light-sensitive proteins found in microorganisms, such as channelrhodopsin-2 (ChR2), can now be genetically expressed in mammalian brain cells, which allows experimenters to optically control cell activity at will. We succeeded in generating a cohort of transgenic mice with consistent expression of a highly light-sensitive ChR2 protein.
In addition, manipulation of the activity of "non-excitable" glial cells in vivo has also become possible. Our experiments show that selective optogenetic stimulation of glia can lead to release of glutamate as a glio-transmitter, which induces synaptic plasticity and can accelerate cerebellar-modulated motor learning. This finding suggests that glia also participate in information processing in the brain, a function once thought to be solely mediated by neuronal activity. We are actively using these optogenetic tools to explore the causal relationship between brain activity and the functioning of the mind.