Study: Stress Hormone Levels Affect Brain's Ability to Determine Location and Direction - Sarmad
A recent scientific study conducted by researchers at Ruhr University Bochum in Germany has shown that elevated levels of cortisol, a hormone released by the body in response to stress, can impair the brain’s ability to determine location and direction, weakening the activity of specialized nerve cells that play a fundamental role in spatial navigation.
According to the study, published in the journal PLOS Biology and reported by the Science Daily website, high cortisol levels led to a decline in participants’ ability to navigate within a virtual environment, accompanied by disrupted regular activity in so-called “grid cells,” which are nerve cells that help the brain determine location and build an internal map of the surrounding environment.
The study involved 40 healthy men, each of whom underwent the experiment on two separate days: one day receiving a dose of cortisol, and the other day receiving a placebo. Participants then performed a spatial navigation test within a virtual environment while undergoing magnetic resonance imaging (MRI).
Participants were asked to navigate through a virtual space resembling a large meadow and reach a group of trees, then identify the shortest route back to the starting point after the trees, which had been used as temporary destinations, were removed.
The tests were conducted in two conditions: the first without fixed landmarks for reference, and the second with a fixed lighthouse that participants used as a navigational reference point.
The results showed that participants made more errors in determining directions and reaching their destinations after taking cortisol compared to the placebo test, regardless of the presence of spatial landmarks or the complexity of the path.
MRI scans revealed that cortisol also affected the activity of grid cells located in the entorhinal cortex, a brain region that plays a key role in location determination and spatial navigation.
Researchers explained that grid cells typically activate in a regular, repeating pattern resembling a grid during navigation, helping the brain form an internal map of the place. However, this activity became less distinct among participants after exposure to cortisol, with the disruption being more pronounced in the absence of fixed landmarks.
These findings may contribute to understanding the relationship between stress and certain neurological disorders, particularly Alzheimer’s disease, since the entorhinal cortex is one of the brain regions affected in the early stages of the disease. The researchers emphasized, however, that the current results do not prove a direct therapeutic or clinical relationship.
