Gray matter of the brain: structure and functions

Almost all of us have heard about the gray matter that one or another person has. In Spain it is a concept that is popularly has been associated with intelligence, but in reality his role is much more important than that.

Gray matter can be found in the brain, yeah, and also its existence has to do with the way in which mental processes related, among other things, with cognition and intelligence develop. But having more or less amount of gray matter does not imply being more or less intelligent. This is so because its function is more general and essential, and has to do with the basic functioning of the nervous system.

What is gray matter?

Gray matter, also called gray matter, comprises the areas of the central nervous system in which neuron somas predominate (that is, the part of the neuron in which its nucleus is located and its "body" from which the branches start).

The gray color of these areas contrasts with the white of the rest of the nervous system, which looks like this because in they predominate the axons of the neurons, that is, the processes that arise from the bodies and that are covered for

myelin, White color.

In qualitative terms, there are no relevant differences between the composition of white matter and that of gray matter: in both there are neuronal bodies, dendrites and axons with myelin. However yeah there are significant differences in the quantities and proportions in which these elements are present in each of them.

So technically gray matter is not a part of the brain, but the material with which some parts of the brain are built.

The distribution of gray matter

The areas of the brain and spinal cord that are made up of gray matter do not form a homogeneous group, but are distributed and in some cases there is white matter between them. However, in most cases these areas are large enough that they can be easily seen with the naked eye.

In the medulla, the gray matter is found in the central and lateral part (in any of its sections, regardless of the height at which it is), but in the brain it is more distributed.

The cerebral cortex, for example, is made up of gray matter, but the same goes for basal ganglia, which are located below, with the deepest and most superficial part of the cerebellum and with many other scattered areas, such as the thalamus and the hypothalamus.

The role of these areas

Unlike what white matter does, in which myelin causes nerve impulses to transmitted rapidly through the axons, the gray matter cannot make the information that flows through it go so fast. The main function of these zones is not to make electricity pass quickly through them, but has to do with the processing of information, whatever the type.

As the content of the information processed by the areas of gray matter is very diverse, the effects of a decrease or an increase of this substance are also varied. That is why injuries in these areas depend on the type of structure they affect. However, no part of gray matter can work without the help of white matter, as they need to be connected to each other to function properly.

Regarding the gray matter of the spinal cord, this is in charge of acting as an information directory, that is, it is where it is decided what information enters and leaves the nerves of the peripheral nervous system and what information must travel up or down the spinal cord. In addition, there are some theories about memory according to which memories are chemically stored within neuronal bodies, much more abundant in this type of brain tissue.

Concluding

The presence of gray matter indicates that the part of the brain in which it is found receives information from many areas of white matter and that, in some way, function as information processing clusters and in which the nerve impulses that travel through the axons meet with a relay that directs them to another destination.

This implies, among other things, that gray matter and white matter are needed to work as they should; not in vain are two types of brain tissue differentiated by the concentration of the part of neurons that predominate more in them (axons or somas), and these small nerve cells form an organic unit that cannot be separated without destroy it.