Stress Alters How the Brain Processes Sound – Neuroscience News

Summary: Chronic stress weakens the brain’s ability to process sounds, requiring louder stimuli to trigger normal responses, according to new research in mice. Scientists found that stress affects inhibitory brain cells, which suppress responses to lower-decibel sounds while maintaining sensitivity to louder noises. This shift may be caused by an overactive population of SST cells, which dampen the activity of other neurons involved in auditory processing.

The findings suggest that stress doesn’t just alter emotional responses but also influences how the brain perceives neutral sensory information. These changes could have implications for stress-related sensory disorders, such as hypersensitivity or difficulty filtering background noise. The research highlights the broad effects of stress on brain function and opens the door for future studies on sensory processing under chronic stress conditions.

Key Facts

• Diminished Sound Processing: Chronic stress reduces the brain’s response to quieter sounds while maintaining sensitivity to louder ones.
• Neural Inhibition Increases: SST inhibitory cells become hyperactive under stress, suppressing other neurons involved in auditory perception.
• Broader Sensory Effects: Stress may alter how the brain processes not just emotional stimuli, but also everyday neutral sensory input.

Source: Ben-Gurion University of the Negev

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.

Chronic stress is known to impact learning and decision-making, but could it also affect how we hear?

Dr. Jennifer Resnik 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,” she explains.

Her findings were just published in PLOS Biology.

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.

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.

“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.

Additional researchers included her students: Ghattas Bisharat, Ekaterina Kaganovski, Hila Sapir, Anita Temnogorod, and Tal Levy.

Dr. Resnik is also a member of the Zelman Center for Brain Science Research.

Funding: The research was supported by the Israel Science Foundation (Grant no. 725/21).

About this stress and auditory neuroscience research news

Author: Ehud Zion Waldoks
Source: Ben-Gurion University of the Negev
Contact: Ehud Zion Waldoks – Ben-Gurion University of the Negev
Image: The image is credited to Neuroscience News

Original Research: Open access.
“Repeated stress gradually impairs auditory processing and perception” by Jennifer Resnik et al. PLOS Biology

Abstract

Repeated stress gradually impairs auditory processing and perception

Repetitive stress, a common feature of modern life, is a major risk factor for psychiatric and sensory disorders.

Despite the prevalence of perceptual abnormalities in these disorders, little is known about how repetitive stress affects sensory processing and perception.

Here, we combine repetitive stress in mice, longitudinal measurement of cortical activity, and auditory-guided behaviors to test if sound processing and perception of neutral sounds in adults are modulated by repetitive stress.

We found that repetitive stress alters sound processing, increasing spontaneous cortical activity while dampening sound-evoked responses in pyramidal and PV cells and heightening sound-evoked responses in SST cells.

These alterations in auditory processing culminated in perceptual shifts, particularly a reduction in loudness perception.

Additionally, our work reveals that the impact of stress on perception evolves gradually as the stressor persists over time, emphasizing the dynamic and evolving nature of this mechanism.

Our findings provide insight into a possible mechanism by which repetitive stress alters sensory processing and behavior, challenging the idea that stress primarily modulates emotionally charged stimuli.