Arzy’s experience focused on demonstrating what very few dared to do: for many years, all phenomena of altered perception, such as seeing shadows or feeling a presence, had been relegated to the paranormal.
Thanks to advances in brain exploration techniques, these phenomena can now be better studied from a scientific point of view.
- Feeling the presence of a person who isn’t really around.
- Feeling in someone’s company or seeing a face on a wallpaper are phenomena that we all already feel.
At least once we have doubted what our senses perceive and that is not why we have lost them, the brain is an organizer of the senses so complex that any change can lead to perception errors.
Shahar Arzy is a professor at the Laboratory of Cognitive Neuroscience at the Ecole Polytechnique in Lausanne, Switzerland.
In his research work, he has experimentally demonstrated the physiological correspondence between hallucinatory states and areas of multisensory integration.
The feeling that there is someone when in reality no one has been described in both psychiatric patients and healthy individuals.
Arzy’s experiment managed to induce the patient to feel a strange shadow, through focal electrical stimulation.
The experiment was conducted on an individual with no psychiatric history, who was stimulated in the left temporoparial junction (TPJ), each time this region was stimulated, the individual began to feel the sensation of having a shadow behind it.
The experience was repeated with the individual in different positions, and in each of them the shadow acquired a position identical to that of the individual, which corroborates that this shadow was most likely a projection of his own body.
This phenomenon is due to multisensory or sensoriomotor disintegration, caused by stimulation in the TPJ zone, previously related to self-training and the distinction between self and non-I.
The temporoparietal junction, as the name suggests, is the area of the cerebral cortex where the parietal and temporal lobe are located. The parietal lobe is closely related to somatosensory mapping and body motor.
In turn, the temporal lobe is responsible for language processing and connections to subcortical areas of emotional processing.
But temporoparietal bonding, in addition to being a center of multisensory integration, is also linked to cognitive processing processes.
Arzy’s experience is based on the intense activation of this region of the brain when dealing with elements such as:
In the experiment, when temporoparietal union was stimulated, the individual did not recognize the shadow generated as his own projection, but as something else. This phenomenon is based on the role of the temporal lobe in the linguistic sense of the self.
The first question that arises from reading Arzy’s experience is: how can we not be aware of such dissociation processes?
Experience shows that these phenomena seem alien to individuals. The main reason is the fragility of the “sense of self” on the part of the brain.
Any structural, electrical or functional change can trigger perception errors, so the sense of self, understood as the ability to differentiate my own body’s perception from other objects, is not as stable as we think.
The amygdala is another subcortical brain structure that is part of the limbic system, this nerve structure is fundamental to the emotional processing of experiences.
In principle, changes caused by TPJ stimulation are alien to our brains, so we react with fear.
We are not used to recognizing our own body as someone else’s, so the amygdala gives a negative emotional response, which in many cases aggravates hallucinations.
Experiments can be as varied as they are strange and, from a clinical point of view, the so-called extracorporeal experiences stand out, the most common being:
As Arzy’s experience shows, these dissociative phenomena can occur in normal individuals without a psychiatric history.
There are also a number of pathologies in which individuals are highly exposed to the brain changes that cause this change, including:
On the other hand, desynchronization in sensory integration can also occur in non-pathological circumstances:
Arzy’s experience is one of those studies that surprises even the most skeptical reader. The ability to recognize our own body is much more complex and fragile than we think.
Moreover, the revolution of these experiments is the fact that many phenomena formerly considered paranormal are now in the hands of science.
Seeing a shadow when walking or taking a mannequin for a person are small hallucinations, small non-pathological perception errors, understanding your nature can always help us better understand ourselves as human beings.