PERCEPTION CHANNELS: WHAT ARE THEY AND THEIR CHARACTERISTICS - ANATOMY AND PHYSIOLOGY - 2025

The perception channels or sensory systems are the different components by which external stimuli are transformed into perceptions. These systems differ from the sensory organs in that the latter refer only to the receptive component.

In human beings there are different types of perception channels, divided according to the origin of the stimuli that are perceived and the type of receptors. The most prominent types of reception channels are interoceptive, proprioceptive and external.

Smell is one of the channels of perception

Despite being different systems, all are characterized by having different components through which they process information and the sensation and perception process occurs. The first component is the sensory receptors, where stimuli initially impact and become nerve impulses.

This first process is called transduction. The second component is the afferent transmission pathways, which consist of the neural pathways through which the information received goes from the organ to the brain; that is, where it is transmitted to be processed.

Finally, the third component corresponds to the cortical areas, where the information is processed and integrated. In addition to all these components, there are also different types of areas that interact with each other.

What are the channels of perception?

There are different types of perceptual channels that have been identified from neurophysiological and psychological (psychophysical) studies.

To be considered channels of perception they must have sensory receptors that respond specifically to a type of energy, and those sensory receptors must be connected to a specific neural structure.

However, that is not all, since it is necessary for sensory information to be finally processed in the brain and result in perception.

Exteroceptive channels

These are the perceptual channels that are related to the so-called five senses.

-The auditory canal (or sense of hearing) has its receptors in the inner ear.

-The visual channel (or sense of sight) has its receptors in the retina of the eye.

-The haptic channel (or sense of touch) has its receptors in the skin.

-The gustatory canal (or sense of taste) has its receptors on the tongue and other areas near the mouth.

-The olfactory channel (or sense of smell) has its receptors in the nose.

Interoceptive channels

In this type of channel the information comes from within the body and the receptors are also located internally. In fact, the receptors are located in vital organs such as the viscera.

This type of channel processes information about the state of these organs, especially related to visceral pain, which allows them to be a kind of alert to negative or unexpected changes.

Proprioceptive channels

In this type of channel the information also comes from within the body, as do the receptors. However, the receptors are not found in organs and viscera. Here the kinesthetic and vestibular canals are located.

-The kinesthetic has receptors in joints and the information it obtains is about the body (its location and movements, among others). This channel of perception is necessary for sensory-motor coordination.

-The vestibular canal has its receptors in the vestibules of the inner ear. This channel is related to head and eye movements, and balance.

characteristics

Each channel of perception has its own characteristics in terms of its sensory organs, its neural pathways and representation in the cerebral cortex. The main characteristics of the exteroceptive channels are shown below.

Visual channel

The sensory organ of the visual channel is located in the retina of the eye. Within the retina there are two types of photoreceptor cells that convert electromagnetic energy; that is, light in nerve impulses.

Photoreceptor cells are rods and cones, which serve different functions. The rods work on vision during the day and the cones respond to night vision.

The optic nerve leaves the retina, which is the afferent pathway that passes through the thalamus and then reaches the visual area in the occipital lobe.

Ear canal

The sensory organ is the ear, where the acoustic waves arrive and are transported by the outer and middle ear, towards the inner ear.

In the inner ear, the cochlea contains hair cells that convert waves into action potentials.

The afferent pathway consists of the VIII nerve or vestibulocochlear nerve that connects to the cochlear nucleus in the brain stem. From there the nerve impulse passes through the thalamus and reaches the auditory cortex.

Haptic channel

The haptic channel has its receptors under the epidermis and is responsible for transforming energy into nerve signals.

These different receptors are the Meissner corpuscles, the Paccini corpuscles, the Merkel disks, and the Ruffini endings. They are not located uniformly throughout the body, but in the most sensitive areas there are more.

These receptors carry their information to the spinal cord and from there to the somatosensory cortex. The haptic channel can identify pressure, cold, heat and pain caused by the stimulus.

Taste channel

The taste canal is a chemical system whose sensory receptors are the taste buds and corpuscles on the tongue, palate and cheeks. Depending on their shape they can be fungiform, goblet or filiform.

The afferent pathway leads to the VII and IX cranial nerve ganglia, which carry information to the medulla oblongata and from there to the thalamus.

Finally, they reach the parietal cortex and the insular and opercular cortex for processing.

Through the gustatory canal it can be determined if the food is salty, sweet, bitter, acidic or umami.

Olfactory channel

The olfactory canal is a chemical sense whose receptors are found in the olfactory epithelium (in the nose), where the hair cells pick up the olfactory stimuli.

In this olfactory epithelium begins the afferent pathway that goes to the medulla oblongata, passing through the lateral olfactory tract that joins the primary olfactory cortex.

The olfactory channel is known to be closely related to memory, through smells that are associated with past experiences; for example, perfumes that quickly remind you of the person with whom you associate.

References

1. Csillag, A. (2005). Atlas of the Sensory New Jersey: Humana Press.
2. Garrido Hernández, GB (2005). Tactile perception: anatomical considerations, psycho-physiology and related disorders. Journal of Medical-Surgical Specialties, 10 (1), pp. 8-15.
3. Grondin, S. (2016). Psychology of perception. Switzerland: Springer International Publishing
4. Jaume Rosselló, EM and Sánchez Cabaco, A. (2014). Attention and perception. Larousse diffuser, Alianza Editorial.
5. Mendoza, JE and Foundas, AL (2008). The Somatosensory Systems. In Clinical Neuroanatomy: A Neurobehavioral Approach. New York: Springer.