Overview: Recent research conducted on mice at Ben-Gurion University of the Negev highlights the detrimental effects of chronic stress on the brain’s auditory processing capabilities. The study indicates that when subjected to prolonged stress, the brain requires louder sounds to elicit standard reactions. Scientists discovered that chronic stress compromises inhibitory neurons, which normally help modulate responses to softer sounds while retaining sensitivity to louder auditory stimuli. This alteration may stem from an overactive population of SST (somatostatin-expressing) cells that inhibit the activity of other neurons linked to sound processing.

The results imply that stress does more than alter emotional reactions; it also impacts how the brain interprets neutral sensory inputs. These findings could have implications for individuals with stress-related sensory issues, such as increased sensitivity to sounds or challenges in filtering out background noise. This research emphasizes the extensive effects of stress on brain functionality and paves the way for further investigations into sensory processing under chronic stress.

Key Insights

• Impaired Sound Sensitivity: Chronic stress leads to a reduced response to lower-volume sounds while keeping the sensitivity to louder sounds intact.
• Increased Neural Inhibition: Under stress, SST inhibitory cells become hyperactive, suppressing the function of neurons responsible for auditory perception.
• Wider Sensory Impacts: Stress may shape how the brain processes not only emotional stimuli but also everyday neutral sensory experiences.

Source: Ben-Gurion University of the Negev

New research from Ben-Gurion University reveals that chronic stress fundamentally alters how our brains process sound, indicating that louder noises are needed to provoke normal reactions during stressful times.

While the influence of chronic stress on cognitive functions like learning and decision-making is well-documented, its effects on auditory perception are less understood.

Dr. Jennifer Resnik from Ben-Gurion University’s Department of Life Sciences aimed to investigate whether chronic stress affects fundamental brain functions, particularly sound processing.

“Chronic stress is a known risk factor for various psychiatric and sensory disorders. However, there is limited research examining how neutral sounds are processed under stress,” she remarks.

Her study, recently published in PLOS Biology, does not delve into the effects of stress on the ear itself. Instead, it focuses on how chronic stress modifies auditory processing in the brain by using mice to explore alterations in sound interpretation.

The research revealed that with ongoing stress exposure, reactions to softer sounds diminished significantly, whereas reactions to louder sounds were maintained.

Additionally, the study identified that one specific type of inhibitory cell became increasingly active during repeated stress, suppressing the responses of other auditory cells. It was found that SST cells became much more active when a sound was presented, while the activity of pyramidal and PV cells fell, explaining the diminished response to softer sounds, according to Dr. Resnik.

“Our findings indicate that chronic stress influences not only our reactions to emotionally charged stimuli but may also alter how we respond to neutral sounds in daily life,” she concluded.

Contributing researchers included her students: Ghattas Bisharat, Ekaterina Kaganovski, Hila Sapir, Anita Temnogorod, and Tal Levy. Dr. Resnik is also affiliated with the Zelman Center for Brain Science Research.

Funding: The research received support from the Israel Science Foundation (Grant no. 725/21).

Further Insights on Stress and Auditory Neuroscience

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.
“Impact of Repeated Stress on Auditory Processing and Perception” by Jennifer Resnik et al. PLOS Biology

Abstract

Effects of Repeated Stress on Auditory Processing and Perception

Chronic stress is a prevalent aspect of modern life and poses a significant risk for various psychiatric and sensory disorders.

Despite the common presence of perceptual disturbances within these conditions, understanding of how chronic stress affects sensory processing and perception remains scarce.

In this study, we utilized repeated stress in mice, continuous measurement of cortical activity, and auditory-guided behaviors to evaluate if the processing and perception of neutral sounds are influenced by sustained stress.

The results indicated that repeated stress alters sound processing, leading to an increase in spontaneous cortical activity while reducing sound-evoked responses in pyramidal and PV cells, alongside heightened responses in SST cells.

These changes in auditory processing resulted in perceptual shifts, notably a decrease in loudness perception.

Furthermore, our findings illustrate that the effects of stress on perception evolve gradually as the stressor persists, showcasing the dynamic nature of this mechanism.

Our research offers insights into potential mechanisms through which chronic stress modifies sensory processing and behavior, challenging the notion that stress primarily influences emotionally charged stimuli.