Stress seems like the fate of modern man, as we juggle careers, parenting, a jungle of red tape and an inundation of Whatsapp messages. Given the omnipresence of stressors in our lives, it’s surprising that modern medicine has not found an objective, physiological way to measure how badly the phenomenon affects us personally. Doctors have had to rely on subjective descriptions by their patients and devise therapy for them by trial and error. Now, however, a new multidisciplinary study at Tel Aviv University could revolutionize medical attention to stress, linking it directly with certain physiological functions.
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While establishing the scientific correlation between mental stress and physiology, the research also moves in the direction of potential development of a blood test to measure how people rebound from stressful situations, and their vulnerability to them.
Our ability to cope with stress and recover from it differs. It also depends on how traumatic the situations are. People how have difficulty recovering from extreme or protracted tension in their lives may develop post-traumatic stress syndrome, depression, or even somatic (physical) conditions, including chronic pain.
The TAU study, recently published in Plos One, focused on more routine stressful situations, and combine scans of subjects' brains using fMRI (functional magnetic resonance imaging) technology and blood tests to check physiological parameters.
The researchers, led by Prof. Talma Hendler, who also heads the Functional Brain Center at Tel Aviv Sourasky Medical Center, and her university colleague Dr. Noam Shomron, distinguished between the participants’ ability to recover from stress and the speed at which their physiological parameters stabilized after exposure to it, as described in the scientists' paper “Targeting the mind/body connection in stress.” The research itself was conducted by doctoral students Dr. Sharon Vaisvaser and Dr. Shira Modai.
“The study is a step toward deciphering the material triangle of brain-body-soul which is the basis of our existence as human beings,” says Hendler. “It offers an objective test to determine our individual mental and physical vulnerability to stressful situations, and could be the basis to develop a diagnostic tool.”
The study exposed 49 healthy men to an experience of social stress. The testees were asked to carry out various cognitive missions, and encountered negative reactions such as “Wrong, start again,” “Others did it better,” “Faster” and so on.
“Man is a social creature, so we all react especially strongly to social rejection, or to unfair treatment,” Hendler explains. “We are familiar with situations like these in day to day life. Most of us experience stress for a moment, but recover quickly and resume our routines. Our study focused on finding how people differ in recovery.”
The reactions of the subjects were checked several times during the stressful situation and half an hour afterward, in terms of various parameters: via their subjective experience, their brain activity and samples of their blood.
The scientists managed to locate a specific change in micro-RNA inside white blood cells in response to stress, Shomron says: “We also discovered that the change in molecular activity in the blood happens in parallel with a specific change in brain activity during stress.”
Special emphasis was placed on the recovery process, looking at how long each participant took to return to his physiological starting point. The scientists assumed that the those whose parameters indicated faster recovery would also prove more resilient to stressful situations. So it was. People who recover more slowly from stress show a more significant molecular reaction in their micro-RNA miR-29c to the stress.
This change also was seen to corresponde with modified connectivity of a major stress-regulation center in the brain, called vento-medial prefrontal cortex, or, vmPFC. This vmPFC helps moderate our reaction to stress, explains Hendler.
In short, the study showed the biological mechanism that mediates between the brain, body and mind when we feel stress.
“A person’s ability to rebound from stressful situations depends on a combination of his genetics with the environment and his experiences during life,” says Shomron. “Every person is born with a certain genetic potential coded in his DNA, but today we know that genes are operated by molecules called micro-RNA, which react and change depending on the state of the body or the mind.”