The other brain by R. Douglas Fields

The brain is a world consisting of a number of unexplored continents and great stretches of unknown territory - Santiago Ramon y Cajal

This amazingly easy to read and understand book, written by Douglas Fields give us a new and fascinating perspective of how the brain functions. Allowing to understand, not only to neuroscientists, the most recent discoveries about the brain. As its name indicates this book is focused in the study of glial cells which are located in the brain and make up to approximately 85% of the cells in it.

In the past neuroscientists dedicated themselves to study only neuron cells to understand the human behavior trough the brain functioning. But two decades ago they realized that glial cells also played an important role in how the mind works. The evolution of brain knowledge is similar to the history of DNA knowledge: scientists first thought that genes caused beings to express certain traits and the rest was junk DNA; but later on they discovered that the so-called "non-coding" parts of the DNA also had an important role in the organism.

According to J. Kwasniak there are (at least) two types of junctions between neurons: chemical synapses and electrical synapses. In chemical synapses there is a tiny space between the membranes of the two neurons, molecules of neurotransmitter are bled into this space by one neuron and taken in by the other. In this way a signal is sent from the pre-synaptic neuron to the post-synaptic one. The signaling occurs when the pre-synaptic cell is firing and the post-synaptic cell is influenced to fire more easily, or less easily in inhibitory synapses. But there is a slightly simpler junction found both in the brain and in other tissues. It is a cluster of tiny channels in one cell membrane that lines up with a similar set of channels through another cell’s membrane so that small chemicals or electrical currents can pass directly between the two cells. The tiny channels can be opened and closed. We think of the brain as using only chemical synapses when actually the gap junctions exist in many areas of the brain, especially between glial cells. They are noted to pass electrical currents in the form of charged ions but may also signal using calcium ions and other chemicals. A group of cells connected by gap junctions have, in effect, a continuous cytoplasm as far as small molecules and electrical charge are concerned. The activity of cells using gap junctions is another whole level of activity in the brain.

Fields explains what is known about how this cells function trough a mix of scientific history, descriptions of the latest neurobiological techniques and chronicles of scientific experiments.He describes the role and importance of glial cells by detailing how they participate in different types of illnesses such as brain cancer, spinal chord injury, “mad cow” infection, HIV and degenerative brain diseases. These new insights of the glia offer hope for breakthroughs in healing these illnesses.

Fields also suggests trough additional evidence that glia play a key role in maintaining mental health, addictions, regulating pain, processing memories, wiring up the baby’s brain and many other functions.

This book envisions that “we are glimpsing a far greater universe of brain function than we had ever imagined.”

Read the Scientific American articles from the author