The stress hormone cortisol can interfere with the brain system that helps people navigate and stay oriented. Researchers from Ruhr University Bochum in Germany found that cortisol weakens the activity of grid cells, specialized nerve cells that are essential for spatial navigation.
The finding comes from an imaging study involving 40 participants who completed a virtual navigation task while researchers monitored their brain activity with MRI. When participants were given cortisol before the experiment, they had more difficulty finding their way, and the normally precise activity patterns produced by grid cells became much less distinct. The findings were published in PLOS Biology.
Stress is already known to influence thinking and behavior, but researchers have had a limited understanding of how cortisol affects the specific brain circuits involved in navigation. Dr. Osman Akan from the Ruhr University Bochum, Department of Cognitive Psychology, worked with colleagues from the Department of Neuropsychology and researchers from University Hospital Hamburg-Eppendorf to examine this process more closely.
Testing Navigation Inside an MRI Scanner
The experiment included 40 healthy men who participated on two separate days. On one day, each participant received 20 milligrams of cortisol. On the other day, they received a placebo. During both sessions, they performed a spatial orientation task while their brain activity was recorded in an MRI scanner.
