Chronic Stress Alters How the Brain Processes Sound

What is it about?

Repetitive stress is a common experience and a significant risk factor for both psychiatric and sensory disorders. Despite the frequent reports of perceptual changes in stress-related conditions, the effects of chronic stress on sensory processing remain poorly understood. In this study, we investigated how repetitive stress influences auditory processing and perception in adult mice. Using a combination of long-term neural recordings and behavioral tests, we found that stress alters cortical activity patterns. Specifically, stress increases spontaneous neural activity while reducing sound-evoked responses in pyramidal and PV cells and enhancing responses in SST cells. These changes in neural activity corresponded with a measurable shift in perception, leading to a reduction in perceived loudness. Importantly, our findings indicate that the impact of stress on sensory perception develops gradually over time, rather than occurring immediately. This suggests that stress-induced sensory changes are dynamic and evolve as exposure to stress persists. These results provide insight into a potential mechanism by which repetitive stress affects sensory processing and behavior. They also challenge the conventional view that stress primarily influences responses to emotionally salient stimuli, highlighting its broader impact on perception.

Featured Image

Photo by Christian Erfurt on Unsplash

Photo by Christian Erfurt on Unsplash

Why is it important?

Changes in perception, such as shifts in loudness perception during stress, may have evolved to help prioritize important sensory information for survival. However, these changes can also become maladaptive, potentially contributing to sensory and mental health disorders. Since accurate sensory processing is crucial for cognitive functions like attention, memory, and decision-making, gradual alterations in auditory processing could have wide-reaching effects. In modern environments, chronic or repetitive stress can trigger physiological and psychological responses that are not always beneficial. Our findings highlight a potential mechanism through which stress influences behavior and emphasize the need to consider its impact on sensory processing, particularly in relation to learning and stress-related disorders.

Perspectives

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The implications of this work could reshape our understanding of how stress affects us: “We often think of chronic stress as primarily influencing complex cognitive functions like decision-making and learning. However, our findings show that it also affects much more fundamental processes, such as the perception of sound. This raises an intriguing question: How much of our daily experience is shaped by chronic stress in ways we don’t even realize?”

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