A study published in the journal Nature Neuroscience revealed that, seeing a person with signs of disease, such as cough or rash, the Human brain can anticipate a risk of infection and activate defense mechanisms of the immune system.
The experiment was led by Andrea Serinoneuroscientist at the University Hospital of Lausanne, Switzerland.
In an interview with Nature herself, he said: “The results illustrate the power of the brain to predict what is happening and select the right response to deal with the problem.”
To simulate an infectious threat without exposing participants to real risks, the researchers used virtual reality glasses (Oculus rift).
Volunteers were exposed to human virtual avatars with flu symptoms such as cough or skin lesions. They approached the participants’ visual field, but never touched them.
A second control group received only one real vaccine against A, without interaction with avatars.
Meanwhile, scientists monitored participants’ brain and immunological reactions through examinations such as electroencephalogram (EEG), functional magnetic resonance imaging (FMRI) and blood analysis.
When participants saw the sick avatars approaching, areas of the brain linked to the “peripersal space”, the immediate region around the body were activated. This reaction is part of a neural system that serves to detect nearby threats, acting as an early alarm.
This process activated the so -called protrusion network, a set of brain areas that identifies important stimuli such as dangers. This led to the release of brain signs to the hypothalamus, which in turn activated the hypothalamus – hypothalum – magnet (HPA) axis, responsible for regulating stress -related hormones and immune response.
This brain activation chain culminated in an increase in innate lymphoid cells (ILCs), rapid response immunological cells, which represent the body’s first defense line.
Volunteers exposed to sick virtual avatars had greater activation of these cells than those who took the vaccine.
In addition, the immune response was only observed in the face of specific infection stimuli. Avatars with expressions of fear (but without signs of illness) did not cause the same brain or immunological effects.
The authors point out that this “early brain alert” represents an important link between the central nervous system and the immune system, hitherto little explored in the absence of real contact with pathogens.
“We show that potential contact with infectious avatars that approach in the peripersonal space, in virtual reality, is anticipated by sensorimotor areas and activates the protrusion network […]. This proactive neural anticipation triggers changes in frequency and activation of innate lymphoid cells, mirroring answers seen in real infections, “they said.
Research also reinforces the concept of “behavioral immune system”, which is the evolutionary tendency to avoid sick people to reduce the risk of infection, something intensely observed during the pandemic.
Despite the findings, the authors point out that the study is exploratory and has limitations: theThe immunological effects were tested only with a vaccine (FLUARIXETETRA 2018–2019). The sample consisted of young healthy adults (average 26 years), which limits the application to other age groups.
It is not yet known whether static images of sick people would have the same effect as the moving avatars. Emotional issues, such as the feeling of disgust, can influence brain reactions and need further research.
The team points out that brain sensitivity to signs of infection, even simulated, is part of a highly adaptive “early detection” mechanism, comparable to the functioning of a smoke detector: it is better to sound the alarm by mistake than failing to a real danger.