Afferent and efferent pathways: types of nerve fibers

It is natural to associate the notions of “neuron” and “brain”. After all, neurons are the type of cell that is normally given the ability to think, reason and, in general, to perform tasks related to the intellect.

However, neurons are also an essential part of the nerves that run through our entire body (alongside glial cells). This is not strange, considering what the function of these nerve fibers is: make certain types of information travel through our organs and cellular tissues. However, while all of these data transmission routes basically do the same thing, there are certain nuances and differences between them that allow us to categorize them according to their function. This is why we are talking about the difference between the afferent path and the efferent path.

Aferencia and eferencia: a letter changes everything

To understand the concepts of afferent and efferent, it is very useful to imagine the functioning of the nervous system as cognitive psychologists do, which they use the computer metaphor as a descriptive model of neural networks. According to this metaphor, the brain and the entire nervous system work like a computer; it has part of its structure dedicated to contact with the environment that surrounds it and another dedicated to working with the data it has stored and processed to obtain new information.

Thus, the neurons of the brain and the spinal cord would be this “internal” part of the computer, while the nerves which spring from the spine and reach the farthest corners of the body are the part in contact with the outside. .

This last part of the nervous system, called the peripheral nervous system, is where the afferent and efferent pathways are located, which are the entry and exit channels of the central nervous system, respectively.

The routes through which sensory information travels

Thus, all information that enters through sensory neurons travels through afferent pathways, i.e. those who transform the information the senses collect and turn it into nerve impulses. Instead, the efferent pathways are responsible for the propagation of electrical impulses intended to activate (or deactivate) certain glands and muscle groups.

So, if we wanted to stick to a simple explanatory diagram of what afference and efference is, we would say that the former informs the central nervous system of what is happening to the rest of the body and environmental data that ‘he receives. , while the efferent neurons are concerned with the “transmission of orders” and the initiation of action.

Likewise, the word afferent is used to refer to the information that travels through these pathways of the peripheral nervous system, while the term efferent is used to refer to the output of data from the system. substances and hormones.

Help to remember better

The distinction between afferent and efferent is very useful in understanding how we perceive and act on the environment, but this can also be quite problematic as it is easy to confuse the two terms and use them to denote the opposite of what it means.

Fortunately, using simple mnemonic tricks, it is very easy to remember what each thing is, and the fact that these words are only differentiated by a letter causes that while remembering one, the one also remembers the other. For example, you can associate the “a” of “afferent” with the arrival a (“arrival” and English), and the “i” of “efferent” with the first letter of “dispatch”.

Neurons on pawn?

Afferent and efferent pathways suggest a hierarchical functioning of the nervous system: while neural groups report what is happening to the rest of the body and transmit commands to implement action plans, strategies and protocolsOthers make decisions and give orders that others will obey. However, the functioning of our nervous system is not as simple as it can be intuitive in this schematic view of the journey that produces nervous information about the length and width of our body, for two basic reasons.

The first is that afferent and efferent neurons don’t just passively transmit information: they also cause it to be transformed. What reaches the spinal cord, glands, and muscles is an explosion of data whose shape largely depends on how he found each of the neurons he traveled through.

The second reason is that while it is true that decision-making depends more on the brain than on the neural networks of the peripheral nervous system, we don’t know who rules whom, because they all occupy a place in a data cycle.

After all, afferent neurons send information to the brain without which action plans cannot be initiated, and how the efferent pathways transmit information will impact the body and the environment which then affects the brain. Afferent neurons and therefore in the brain. Consider, for example, keeping a box of cookies so as not to fall into the temptation to snack between hours: a change of environment then makes us think and feel differently than we would with the box of cookies in view.

Ultimately, afferent and efferent neurons may have a simpler and easier task to study than that of brain nerve cells, but they continue to play a vital role in our daily lives.

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