Chronic stress changes the way our brain processes sounds, according to new research conducted on mice at Ben-Gurion University of the Negev. For instance, sounds need to be louder during chronic stress to trigger similar responses.
Red Alert incoming rocket and drone alarm sirens are especially loud throughout Israel — a lifesaving measure to ensure Israelis get to a safe space in time to avoid an attack.
Chronic stress is known to impact learning and decision-making, but but until this study was carried out, it was not known whether or how that stress might affect one’s hearing.
Dr. Jennifer Resnick from Ben-Gurion University’s Department of Life Sciences set out to find whether stress influences basic brain functions, like processing 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,” Resnick says.
The findings of the study were published in PLOS Biology.
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.
The researchers discovered that chronic stress has a clear effect 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.
The scientists 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, Resnick says.
“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 concludes.
Additional researchers included students Ghattas Bisharat, Ekaterina Kaganovski, Hila Sapir, Anita Temnogorod, and Tal Levy. Resnik is a member of the Zelman Center for Brain Science Research.
The research was supported by the Israel Science Foundation (Grant no. 725/21).
