Delay dispersion in nerve fibers determines neuron detection type and predicts brain column diameter.

Brain cells fire very few electrical pulses, called spikes, often fewer than one spike per sensory window. Because of this, the exact timing of spikes carries crucial information. However, scientists did not know what decides whether a neuron spots a single combined event or two events arriving in a specific order. The researchers studied this using simulations of an integrator-neuron model. In their framework, signals travel along nerve fibers called axons with different physical delays. These delays act like a key. When the delays exactly balance the timing gaps between incoming spikes, the signals land on a cell branch at the exact same moment. This triggers an all-or-none output via calcium plateau thresholds. The researchers found that the spread, or dispersion, of these delays decides what the neuron detects. A narrow spread detects single events, while a wider spread creates sequence detectors that track the order of events.

Why it matters

This explains how individual neurons decide what to respond to in sensory input, which is key for understanding brain function. It could inform treatments for neurological conditions where timing is disrupted.

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