A new computational study reveals that chronic stress reshapes brain networks in a way that makes them resilient but rigid, sacrificing flexibility for stability. Researchers from the University of [Affiliation] trained recurrent neural networks on a working memory task and simulated chronic stress by strengthening inhibitory-to-excitatory synapses—the only mechanism among eight tested that matched three key signatures of prefrontal dysfunction: inhibitory dominance, excitatory hypofunction, and impaired task performance.
How They Modelled Stress
The team, led by Mauricio A. Diaz and colleagues, trained networks to hold an item in memory over a delay. They then applied eight different synaptic or activity modulations to mimic stress. Only boosting the strength of inhibitory neurons onto excitatory neurons (stronger I→E synapses) simultaneously caused all three dysfunction signatures. This fits cellular data showing that chronic stress shifts excitatory-inhibitory (E/I) balance toward inhibition in the prefrontal cortex.
The Resilience-Flexibility Trade-Off
Comparing naive networks with those resiliently trained under the stress mechanism, the researchers discovered that resilient networks maintained task performance even under high stress by staying in the same dynamical subspace and energy regime. However, when tested on longer memory delays than trained, resilient networks performed worse than naive networks. This trade-off persisted across different stress magnitudes and network sizes, mirroring the shift toward rigid, habit-like behavior seen in chronically stressed animals.
Why It Matters for Your Brain
This study offers a computational explanation for why chronic stress can make you more efficient at routine tasks but less able to adapt to novel situations. The neural system "specializes" to cope with stress, but at the cost of cognitive flexibility—a key component of fluid intelligence and problem-solving.
What You Can Do
- Practice flexible thinking: Deliberately engage in novel activities that challenge your routine, such as learning a new language or solving puzzles.
- Manage chronic stress: Techniques like mindfulness, exercise, and adequate sleep help restore E/I balance in prefrontal circuits.
- Test your cognitive flexibility with brain training exercises that vary difficulty and context.
Source: arXiv q-bio.NC
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