Turns out we were wrong about brain cells 'stretching' their electrical signals to stay alive when they aren't being used.
March 25, 2026
Original Paper
Unreliable homeostatic action potential broadening in cultured dissociated neurons
bioRxiv · 2025.05.09.653135
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The Takeaway
It was recently believed that neurons compensate for long periods of 'silence' by broadening their electrical spikes to allow more calcium in and maintain stability. This study found that this supposed universal backup mechanism does not actually occur in the brain's cortex, proving that our current understanding of how neurons self-regulate is fundamentally flawed.
From the abstract
Homeostatic plasticity preserves neuronal activity against perturbations. Recently, somatic action potential broadening was proposed as a key homeostatic adaptation to chronic inactivity in neocortical neurons. Since action potential shape critically controls calcium entry and neuronal function, broadening provides an attractive homeostatic feedback mechanism to regulate activity. Here, we report that chronic inactivity induced by sodium channel block does not broaden action potentials in neocor