Perceptual learning: characteristics and brain areas involved
Sep 14, 2023
There are many ways to learn, and many are well known to everyone. But There are others that are not so popular, such as perceptual learning, which occurs in us constantly..
The mechanism underlying this peculiar way of acquiring knowledge is fascinating. We invite you to discover it through the following paragraphs.
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What is perceptual learning?
Perceptual or perceptual learning is a mechanism by which, through our senses (especially sight, since it is what provides the vast majority of information from our environment), we perceive stimuli in a certain way and not another, in a stable way that, however, can be modified through certain procedures.
A classic definition is the one made by Gibson in 1963, referring to perceptual learning as any change that occurs within the framework of the perception system, as long as it presents a certain stability, and comes from the subject's experience in relation to a certain stimulus (or stimuli).
Due to this phenomenon, if we show the same photograph to a varied population sample and ask them to discover what they see and what draws their attention in particular, we will obtain very varied responses, since some will pay attention to the emotional expression of the people represented, others in the clothing, others in the landscape and the weather, others in the location where they are located, etc
The most curious thing is that even the same person's response can change over time, depending on their own learning, your experience with similar stimuli, your own thoughts and concerns at the time of doing the study, and many other factors. Therefore, we would be verifying that the response given depends on the receptor and the internal processing it carries out, and not on the stimulus itself.
Neurophysiology of perceptual learning
But what are the psychophysiological bases that explain perceptual learning? In one of the experiments carried out to find out (Hamamé, 2011), an exercise was proposed to the volunteers in which they had to visually finding certain elements within an image that included both that pattern and other different ones that acted as distractors.
After several days of repeating this task, it was found that there was an evident improvement, and therefore a learning in their way of perceiving through sight (they were increasingly more skillful and needed less time to find the objective they were looking for), at least for those specific stimuli and in those conditions.
In this study, the electroencephalogram was measured during the repetition of the task, and the conclusion was reached that there were, not one, but three changes at the neurological level that would explain the improvement in learning perceptual. These changes were observed in the frontal lobe, which cognitively regulates the visual sensory information processed by the occipital lobe..
Let's now look at each of these three changes in detail.
1. N2PC Wave
On the one hand, it was found that the N2PC wave was increasingly larger the more the subject repeated the activity (and therefore, the more I learned). And this wave has a direct relationship with the level of attention in processing.
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2. P3 wave
On the other hand, it was also determined that a second wave, in this case P3, was present in the same grade the entire time the task lasted, regardless of the stimulus they had to look for in that moment.
The P3 wave signals the search for significant changes in the environment, and if it remained with the same intensity all the time it means that it was associated with the search task in general, and not with the specific pattern that they had to find each time.
3. Brain oscillation
The third characteristic regarding perceptual learning that was verified in the EEG measurement was that throughout the process a brain oscillation could be observed, a neurological mechanism that occurs when action potentials are reorganized to prepare the creation of neural networks, and therefore to forge learning in our brain.
In fact, brain oscillations were observed at two levels: in high frequency (>40Hz), or gamma, and in low frequency (8 to 10 Hz), or alpha. The important thing here is to know that alphas occur during the desynchrony of neurons and therefore in the destruction of neuronal networks, while gamma are observed during the opposite process: when new networks are established and therefore the neurons are synchronizing.
The curious thing about the experiment is that, in the first phases, an increasing gamma frequency was observed, while it decreased as the tests progressed. On the contrary, the alpha frequency did exactly the opposite: it started weakly and gradually intensified the more the exercises were practiced, which made the authors think that the perceptual learning process was occurring in two different times.
First of all the brain would facilitate the search for the desired visual pattern by creating neuronal assemblies for this purpose. But as the subject trains and acquires skill in this task, these neural networks disintegrate, to leaving only certain brain cells (the most efficient for that exercise) in charge of this process. It is a way to optimize the procedure, allocating the minimum resources but obtaining the best result.
What is concluded in this study is that the entire perceptual process in the subject is active, and occurs through the exposed mechanisms and phases.
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Brain areas involved
We have already seen the neurological procedure of perceptual learning and the changes at the neuronal level that occur during this process, but now we are going to see which are the brain regions that are involved in one way or another in all this mechanism.
The first place where changes can be found at the synaptic level is the sensory association cortex.. Through the functional neuroimaging technique, it has been proven that when a person evokes elements stored in memory of it, whether visual, auditory or other types, there is significant activity in this area of the cortex.
This region is also activated when we use short-term memory, during the perception process. In fact, it is proven that the use of the transcranial magnetic stimulation technique in the sensory association cortex Its secondary effect is a disturbance in the process of remembering the stimuli perceived with the active or primary memory.
Another brain area that is involved in perceptual learning is the prefrontal cortex, since it is also responsible for the tasks involved in the functioning of short-term memory. It would be in this part of the brain where the data about the elements that we have to remember would be integrated.
When perception processes occur through the eye (that is, in most cases), the primary visual cortex would be activated. This collects data from the lateral geniculate nucleus, another brain structure, in this case located in the thalamus., and responsible for a first processing of the data obtained, before sending it to the extrastriate cortex.
Additionally, the primary visual cortex can use two different pathways, depending on the task it is performing. When it comes to recognizing a certain element, the ventral route is taken, which goes through the cortex of the inferior temporal lobe. Therefore, if this area were affected by some type of injury or disease, it is possible that the subject would lose the ability to recognize certain objects.
On the other hand, there would be the dorsal pathway, a route that passes through the cortex of the posterior parietal lobe, and whose function would be related to the location of a specific element in space.
The visual association cortex is a key area during perceptual learning, since it is in this place and through the establishment of successive neuronal connections or synapses that the process of visual recognition of a given stimulus is generated.
Finally, it should be noted that such an everyday and standardized procedure, but in reality enormously complex, such as recognizing a face, is possible thanks to the synapses that are generated within the aforementioned associative visual cortex, but in a very specific area known as fusiform area of faces, so this would be another part of the brain active during some of the learning procedures perceptual.
- Gibson, E.J. (1963). Perceptual learning. Annual review of psychology.
- Price, M.S.M. Henao, J. (2011). Influence of visual perception on learning. Science and Technology for visual and ocular health. Dialnet.
- Hamamé, C.M. (2011). Active vision and perceptual learning: How experience changes our visual world. Lyon Neuroscience Research Center, Brain Dynamics and Cognition.
- Hamamé, C.M., Cosmelli, D., Henriquez, R., Aboitiz, F. (2011). Neural mechanisms of human perceptual learning: electrophysiological evidence for a two-stage process. PLoS One.