People under stress can have difficulty orienting themselves in space. Researchers from Bochum have discovered the reason.
The stress hormone cortisol disrupts the brain’s navigation system. This impairs the function of grid cells, which play an important role in orientation. This was verified in an imaging study involving 40 people, including researchers at Ruhr University Bochum in Germany. Participants completed a virtual navigation experiment while their brain activity was recorded in an MRI scanner. If the subjects had been given cortisol before the experiment, their performance was even worse, obscuring the exact activity patterns of the grid cells. The results were published in an online journal PLOS Biology March 12, 2026.
Although it is well known that stress affects human behavior and thinking, it was largely unknown how cortisol disrupts the brain circuits that control navigation. A team working with Dr. Osman Akan from the Department of Cognitive Psychology at Ruhr University Bochum, colleagues from the Department of Neuropsychology, and researchers from Hamburg-Eppendorf University Hospital set out to investigate this very question.
Virtual orientation test in MRI scanner
Forty healthy men each participated in the experiment on two different days. One day, the subjects were given 20 milligrams of cortisol. A placebo was administered on the second day. Each day, they underwent an orientation test while their brain activity was recorded in an MRI scanner.
In the test, subjects were placed in a vast virtual grassland landscape and had to move one after the other towards different trees that disappeared as they arrived. They then had to find a direct path back to their starting point without any indication of where that path was. For some of the tests, the environment had no permanent landmarks at all, and only trees were treated as temporary targets. In other parts, lighthouses served as permanent reference points.
Disorientation due to cortisol
Cortisol significantly worsened participants’ orientation. Compared to their results after taking a placebo, they made far greater errors in finding their destination, regardless of spatial landmarks or path complexity.
Neuronal coordinate systems fail under stress
The influence of cortisol was also evident in functional MRI recordings. A subset of neurons in the entorhinal cortex fire in a grid pattern during spatial tasks, unaffected by cortisol, and are therefore called “grid cells.” In other words, it constitutes the GPS system within the human body.
Under the influence of cortisol, grid cell activity patterns became less distinct. In particular, cells were virtually ineffective when navigating an environment without landmarks. “During stress, the brain loses its ability to effectively utilize its internal navigational maps,” Akan explains.
Researchers found that cortisol also led to increased activation in another region of the brain, the caudate nucleus.
This indicates that the brain attempts to compensate for the loss of the primary navigation system in the entorhinal cortex through alternative strategies. ”
Dr. Osman Akan, Department of Cognitive Psychology, Ruhr University Bochum
Significance for understanding Alzheimer’s disease
The entorhinal cortex is one of the first brain regions affected by Alzheimer’s disease. “Chronic stress is a risk factor for dementia, so our study uncovers an important mechanism for how stress hormones destabilize this sensitive region,” explains Professor Akan.
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Reference magazines:
Will, O. Others. (2026). Cortisol treatment impairs pathway integration and alters grating representation in male human entorhinal cortex. PLOS Biology. DOI: 10.1371/journal.pbio.3003661. https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3003661
