Summary: New research in mice shows that chronic stress weakens the brain’s ability to register quieter sounds, requiring louder stimuli to evoke normal responses. The study identifies changes in inhibitory neurons—particularly somatostatin-expressing (SST) cells—that suppress responses to lower-decibel sounds while leaving sensitivity to louder sounds relatively intact. These neural changes suggest stress can alter basic sensory processing as well as emotional responses.
The results indicate that chronic stress reshapes how the brain processes neutral auditory information, which may contribute to stress-related sensory symptoms such as difficulty filtering background noise or altered loudness perception. The study highlights broad, evolving effects of prolonged stress on cortical function and points to cellular mechanisms that could be explored in future research on sensory processing disorders.
Key Facts
- Diminished sound processing: Prolonged stress reduces cortical responses to quieter sounds while responses to louder sounds remain comparatively preserved.
- Increased neural inhibition: Under chronic stress, SST inhibitory cells become more active and suppress the activity of pyramidal and parvalbumin (PV) cells involved in auditory perception.
- Broader sensory impact: Stress appears to alter processing of neutral sensory signals as well as emotional cues, with potential implications for sensory and psychiatric disorders.
Source: Ben-Gurion University of the Negev
Chronic stress alters the brain’s auditory processing, new mouse experiments at Ben-Gurion University of the Negev show. Over time, sounds must be louder to produce the same cortical responses.
Chronic stress is well known to impair learning and decision-making, but its effects on basic sensory processing are less clear. Could repeated stress change how the brain interprets everyday, neutral sounds?
Dr. Jennifer Resnik and her team in the Department of Life Sciences asked whether repeated stress changes cortical sound processing. Rather than studying the ear itself, they recorded how the auditory cortex of mice responded to sounds over a prolonged stress exposure and linked those neural changes to behavior.
Their study, published in PLOS Biology, tracked cortical activity and auditory-guided behaviors across time. The researchers observed a consistent trend: as stress continued, spontaneous cortical activity rose while sound-evoked responses to lower-intensity tones weakened. Responses to louder sounds, however, remained relatively robust.
The team explored the cellular basis for this effect and found a shift in the balance of inhibition and excitation. Sound-evoked firing increased markedly in SST inhibitory cells, while firing in excitatory pyramidal neurons and in PV interneurons decreased. This selective increase in SST activity likely dampened cortical responsiveness to quieter stimuli, producing a perceptual shift in loudness detection.
“Our results suggest repeated stress does more than alter reactions to emotionally salient events,” says Dr. Resnik. “It can gradually change how the brain registers ordinary, neutral sensory input, potentially affecting perception and everyday function.”
These observations culminated in measurable changes in perception: stressed mice showed reduced loudness perception relative to non-stressed controls. Importantly, the effects developed gradually as the stressor persisted, indicating a dynamic process rather than an immediate, static impairment.
Co-authors on the project included students Ghattas Bisharat, Ekaterina Kaganovski, Hila Sapir, Anita Temnogorod, and Tal Levy. Dr. Resnik is affiliated with the Zelman Center for Brain Science Research at Ben-Gurion University.
Funding: This 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: Image 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. Though perceptual abnormalities are often reported in these conditions, the effects of prolonged stress on sensory processing remain poorly understood.
This study combined a mouse model of repetitive stress with longitudinal cortical recordings and auditory-guided behavioral tests to evaluate whether neutral sound processing and perception are altered by prolonged stress exposure in adulthood.
The researchers found that repeated stress increased spontaneous cortical activity, reduced sound-evoked responses in pyramidal and PV cells, and enhanced sound-evoked responses in SST cells. These neural shifts were associated with a measurable decline in loudness perception and developed gradually as stress continued.
These findings offer a potential mechanism by which repeated stress reshapes sensory processing and behavior, suggesting that stress-related changes extend beyond emotional reactivity to include basic perceptual functions.