Researchers found that stressed mice needed louder sounds to trigger normal brain responses. This shift seems to be linked to certain brain cells becoming overly active while others are suppressed, altering how sounds are processed.
Their findings suggest that long-term stress doesn’t just heighten our emotional responses but may also dampen our ability to perceive neutral sounds, which could have implications for sensory processing disorders and mental health.
Chronic stress alters how we hear sounds
Chronic stress can change the way the brain processes sound, according to new research on mice at Ben-Gurion University of the Negev. The study found that under prolonged stress, the brain requires louder sounds to produce the same response as before.
While chronic stress is known to affect learning and decision-making, its impact on hearing has been less explored. Dr. Jennifer Resnik from Ben-Gurion University’s Department of Life Sciences set out to investigate whether stress alters basic brain functions, including how we process sounds.
“We know that chronic stress is a risk factor for several psychiatric and sensory disorders. However, there is little research on how our brains process neutral sounds under chronic stress,” she explains.
Her findings were published on February 11 in PLOS Biology.
Investigating the brain, not the ear
Dr. Resnik’s research didn’t focus on how stress affects the ear itself. Instead, her team examined how chronic stress changes auditory processing in the brain, using mice to uncover how stress might alter the way sounds are interpreted.
They discovered a clear effect of chronic stress on sound responses over time. Sounds at lower decibel levels triggered significantly weaker reactions as the stress persisted, while the mice maintained strong responses to higher decibel sounds.
A cellular shift under stress
They also discovered that this effect may be driven by one type of inhibitory cell becoming vastly more active under conditions of repeated stress and suppressing other cells. They found that SST cells in the brain began to fire much more strongly when a sound was played whereas the activities of pyramidal and PV cells dropped. That may explain the dampening of sounds, according to Dr. Resnik.
Stress may alter everyday sound perception
“Our research suggests that repeated stress doesn’t just impact our reactions to emotionally charged stimuli—it may also alter how we respond to everyday neutral stimuli,” she concluded.
Source:Sci tech daily
Bd-pratidin English/ Afia
