The timing of brain

There are approximately 100 billion neurons within the brain. Most of the time they are firing and communicate information with each other. Just imagine the scene of a crowded restaurant, where people are talking to each other. How noisy would it be? You wouldn’t get any information from these people but noise. However, our mind is very good at separating and groupping information from different sources according to different purposes to generate the lucid mental image.

To achieve this goal, establishing large-scale connection might be a solution. Local communication between neurons may be facilitated by wiring, but there are only a few of connections between brain areas in global scale. The fast flow of information couldn’t be achieved by these connections. Then how could brain regulate the information flow?

The answer is timing. There are several temporal scale in brain, ranging from seconds to tens of milliseconds. The temporal scale is regulated by brain rhythm, such as theta oscillation and gamma oscillation. The neural oscillations are among the earliest discoveries in neuroscience. Until now, their functions start to become known to us, but only a little.

Back to our question, how does brain control information flow?    It turns out that time is the key. When several neurons fire within a specific temporal window, they bind with each other. The information they represent group together. if neuron fires ten milliseconds late and miss that temporal window, then the information of this neuron won't be grouped into the former group. We call firing simultaneously synchrony. Just a few connections   with inhibition output can achieve synchrony. It is very efficient.

Neurons fire synchrony in local scale to process information, and then bind with neurons of distant areas through global synchrony. Information is grouped with high temporal precision.
Patient who have mental disorder usually show abnormal neural oscillations. For example, schizophrenia patients show unusual gamma oscillation. The medicine which alleviates the symptoms decreases abnormal gamma oscillation.

If we view brain as an information-processing  system, then its heart or pacemaker is the neural oscillation. The timing is the key to successful information processing