Japanese researchers have discovered a neural circuit driving physical responses to emotional stress. This is located in the deep areas of the brain, called the dorsal peduncle cortex and dorsal tecta tenor (DP / DTT), which send stress signals to the hypothalamus, a small region of the brain that controls the vital functions of the body.
Understanding the neural mechanism underlying physical reactions to stress
The stress emotional activates the sympathetic nervous system, which causes physical reactions, such as increased blood pressure and body temperature, and a faster heart rate. These reactions are thought to be coping mechanisms in humans and many other mammals, which improve physical performance in combat or flight situations.
But today, while most people are rarely faced with such situations, these reactions could have a detrimental effect on their health. Excessive stress can for example cause symptoms such as psychogenic fever which, as the name suggests, results in an abnormal increase in body temperature.
To develop strategies for treating stress-induced symptoms, it was first necessary to understand the neural mechanism that underlies physical reactions to stress. To this end, a research team led by the professor Kazuhiro Nakamura and the designated assistant professor Naoya Kataoka, from the Graduate School of MedicineNagoya University, conducted a study in which tracers were injected into the brains of several rats, which were subjected to a stressful event (intimidation by a dominant rat).
Tracers have shown that brain areas DP / DTT were particularly active when exposed to stress. To examine in more detail the role of these brain areas in the stress response, the researchers altered the connections of these areas withhypothalamus and again exposed the rats to the same stress. And it turns out that the rats showed no physical response induced by stress, no increase in blood pressure or body temperature, no acceleration of heart rate.
Published in the journal Science, this new work demonstrates that the areas DP / DTT together are responsible for sending stress signals to the hypothalamus, and therefore blocking the circuit DP / DTT to the hypothalamus can lead to a drastic reduction in stress symptoms in rats.
” DP / DTT are parts of the brain that are involved in the treatment of emotions and stress “, Summarizes the professor Nakamura. ” The DP / DTT-hypothalamus circuit we discovered therefore represents a brain mechanism for a ‘body-mind connection’, which can be a potential target for the treatment of stress-related disorders such as panic disorder, stress disorder trauma (PTSD) and psychogenic fever “Concludes the researcher.