Even the smallest regions of the brain are made up of many different types of cells, each with a unique purpose. Furthermore, each cell in the brain makes electrophysical connections with thousands of other cells. These multiple signals make up pathways in the brain, which themselves communicate with each other. Thus, the astounding range of human intellectual prowess is a result of interactions between billions of neurons.

The complexity of the brain makes it a challenging subject for researchers to study. Recently, brain research was given a huge push forward with the discovery of a new field called optogenetics, which uses light to stimulate targeted neural pathways in the brain. Neurons can be genetically programmed to respond to light. By stimulating these neurons, it becomes possible to study the brain’s processes with a high degree of resolution, and even to control the behavior of flies or small mammals that were thus modified.

To solve a problem, all we need to do is shed a little bit of light. We know that light does not only illuminate, it is a physical force that, among many other things, drives plant growth, which all of us rely on for survival. Now we are beginning to understand the role of light in shaping brain processes as well.

The physical world is parallel to and dependent on the spiritual world for its existence. In spiritual terms, light is G-dly revelation, which supports all of existence. “Let there be light” was the first of 10 Divine utterances that brought the world into being. However, G-d saw that His light was too powerful for the world to withstand, and He took that initial light and concealed it until the time of Redemption.

Divine light is an expression of Divine love, of His desire to bestow His goodness upon His creation. But it is also an expression of Divine love to withhold part of that light – to give in a measured form, to the extent that we are able to accept and contain it.

It may sometimes feel as though G-d is hiding from us when He conceals His light. Actually, He is giving us an opportunity, an opening to discover Him ourselves, through our own efforts. We were created with sensitivity to the Divine deeply rooted in our mind and soul. However, it is up to us to nurture it, to use that light to guide our behavior, to nurture and to give life.