Perceptual channels: types, characteristics and functioning.

A classification of the channels of perception of the human body.

Perception is a process performed by all human beings. By definition, it is a brain mechanism where, through a series of associations of different stimuli, the brain interprets an internal reality of what is happening in the environment. Basically, perception could be defined as the physiological event of sensation.

Every living being is related to the environment, since one of the indispensable conditions that life itself must fulfill is the capacity of the organism to communicate with the external, as well as nutrition and reproduction. Not all living beings relate to the environment in the same way, but there must be a certain degree of perception of the external for life to be considered as such.

For example, some bacteria possess structures known as magnetosomes, which, based on their alignment, allow microorganisms to orient themselves magnetically in a water column. Fascinating phenomena such as these raise many questions: Do evolutionarily simple organisms have "senses"? What are the channels of perception that characterize human beings? Do we really have 5 senses? If you're still wondering, don't worry, because today we address all of these issues and more.

What are the channels of perception?

The channels of human perception or senses are the physiological mechanism of sensation, that is, the reception of stimuli (external and internal) by means of the sensory organs.. The process of perception occurs on the basis of 3 pillars, which can be summarized in the following list:

• Biological factors: external stimuli captured by the 5 senses, which will be explored in the following lines.
• Psychological factors: refers to the set of neural processes carried out by the brain, i.e. the image created from the stimuli, associating with previous experiences in order to recognize or learn them.
• Experience: based on the exposure to a certain stimulus, human beings react and understand differently what surrounds us.

It should be noted that, although experience is an intrinsically subjective factor, the rest of them can also be differentiated, although they follow the same process in all human beings.. For example, studies have shown time and again that completely blind people try to "compensate" for their condition by developing hearing mechanisms of exceptional finesse. Although the Biological process is the same, its development varies based on individual needs.

Types of perception channels in humans

We are going to tell you, briefly, what the 5 senses consist of. However, we will not take too long, as we find it of special interest to record other channels of reception that are not usually explored in humans. Let's get down to it.

Sight

At the biological level, the sense of sight is considered one of the most important senses in humans.. The organ in charge of receiving external stimuli and sending them to the brain is, this time, the eyes. When light passes through the cornea and the lens of the eyeball (through the pupil), an inverted and real image is formed on the retina.

This stimulus in the form of an image is carried by the optic nerve to the cerebral cortex, where the message is interpreted at a psychic-chemical level. The eyes have approximately 125 million rods that help us to see shapes and 7 million cones that differentiate colors, but we are not much less the living beings with the most developed sense of sight.

2. Ear

The sense of hearing allows us to capture the sounds that occur in the environment, a fundamental ability to locate us in the three-dimensional environment and act based on what surrounds us. The ear picks up events in the environment through vibrations of the medium, which range from 20 to 20,000 Hertz..

In addition to hearing, the auditory apparatus plays many more essential roles in maintaining human physiological integrity. For example, the vestibular system located in the inner ear is responsible for coordinating balance. Vertigo, dizziness and accident proneness are clinical signs that characterize people with a damaged vestibular system.

3. Taste

Taste allows us to identify the flavors of the food we are going to eat. The main organ involved in this channel of perception is the tongue, which is covered with taste buds that contain the sensory receptors necessary to taste. which contain the sensory receptors necessary to form the concept of "taste" (the taste buds).

As a curiosity, it is worth noting that the widely cited "map of the tongue" reports very little information at the physiological and anatomical level. In fact, although there are certain differences in the concentrations of taste receptors in different parts of this organ, the variations have been conceived as insignificant. The process of tasting is much more complex than was once thought.

4. Touch

It is the perception of pressure, usually the skin. The sense of touch is essential for survival, as it allows us to interpret when we are in danger in the environment. It allows us to interpret when we are in danger based on a series of receptors specialized in the perception of various environmental characteristics.. We will delve a little deeper into this concept in the following lines.

5. Smell

Olfaction is the sense sense in charge of processing and detecting odors, based on suspended particles present in the environment (it is chemical in nature, like taste). (it is chemical in nature, just like taste). Through inspired air, these molecules come into contact with the olfactory epithelium of the nasal cavity which, after a series of connections, sends messages to the olfactory bulbs. These are responsible for processing, encoding and directing information to other areas of the brain.

It is interesting to know that the human being can detect about 10,000 different odors and that, at a culinary level, the sense of smell is considered as an accessory to taste. Have you ever wondered why food does not taste like anything when we have a cold? During this clinical condition, the olfactory receptors are isolated by nasal mucus and, therefore, we lose a very high percentage of information when it comes to interpreting what we are eating at a cerebral level.

Other "senses" in humans

There are still more senses to be discovered, although they are not directly related to the 5 main blocks we have shown you. Some of them are associated with touch, while others report internal information that is not directly linked to any of the previously mentioned. In this list, we present some of them:

• Thermoreception: encompasses the perception of heat and its absence. The thermoreceptors of the skin are completely different from those that identify the thermal balance of our internal organism.
• Nociception: perception of pain. Not all pain receptors are found in the skin, as they are also found in joints, bones and viscera.
• Proprioception: the perception of our own body parts and their location in three-dimensional space.
• Equilibrioception: perception and maintenance of balance.

One might think that thermoreception and nociception are events completely linked to the sense of touch, but this is not always the case. Intrinsically, "touch" encompasses everything we can feel through the skin, but it turns out that heat, cold and pain can also be perceived in other internalized areas of the body that have little to do with the dermis and epidermis.

An example of this are the visceral nociceptorsvisceral nociceptors: most of them are high-threshold or nonspecific amyelinic fibers, but they register perceived damage to the organs of our body. In this case, information is received from the internal and, therefore, it is far-fetched to link such an event to touch.

Something similar happens with equilibrioception. Yes, the balance system is in the ear, but it is not explicitly and directly linked to hearing itself. A deaf person can have a good sense of balance, although it is more difficult to maintain posture and avoid falls when such a large amount of information as that gathered by the ear is missing.

Summary

As you have seen, the typical classification of perceptual channels is flawed on many fronts, however useful it may be for educational and informational purposes. For example, the map of the tongue has been refuted on multiple occasions, since dividing this organ into circumscribed and clearly delimited taste sections is, to a large extent, untrue.

On the other hand, human beings "feel" much more than what can be encompassed by sight, hearing, taste, touch and smell. The perception of our own body, the balance of our locomotor system, internalized pain and the perception of internal heat are physiological events that cannot be fully explained by the classical senses. These dilemmas make it clear that the more we know about our body, the more we have yet to know about it.

Bibliographical references:

• The sense of sight, oftalvist. Retrieved March 6 from https://www.oftalvist.es/blog/sentido-de-la-vista/.
• The sense of taste, EDUMEDIA. Retrieved March 6 from https://www.edumedia-sciences.com/es/media/478-el-sentido-del-gusto#:~:text=El%20gusto%20es%20el%20sentido,del%20sabor%20es%20la%20lengua.&text=Tambi%C3%A9n%20se%20ilustra%20la%20transmisi%C3%B3n,trav%C3%A9s%20de%20las%20fibras%20nerviosas%20nerviosas.
• Functioning of the ear, RDR. Retrieved March 6, from https://www.rdr.com.mx/funcionamiento-del-oido/#:~:text=The%20sense%20of%20the%20or%20of%20the%20addled%20us,move%2C%20not%20lose%20the%20balance.
• Perception as a means of individual development. (Fundamental factors.), UP. University of Palermo. Retrieved March 6 from https://fido.palermo.edu/servicios_dyc/proyectograduacion/detalle_proyecto.php?id_proyecto=1126#:~:text=Perception%20is%20a%20process%20that%20occurs%20in%20your%20environment.&text=The%20human%20being%20is%20distinguished%20by%20his%20capacity%20to%20reason.