Wondered How Your Brain Makes Decisions? Scientists Map 600,000 Neurons Firing In Sync

Last Updated:September 10, 2025, 16:39 IST

Scientists mapped brain activity, recording 600,000 neurons across 279 regions, revealing decision-making process.

The work challenges older models that suggested decision-making was confined to small clusters of neurons. (Image Credit: International Brain Laboratory)

Neuroscientists from 22 laboratories created the first comprehensive map of brain activity during decision-making, recording signals from more than 600,000 neurons across nearly the entire mouse brain. The data, gathered from 139 mice over seven years, covers 279 brain regions- representing about 95% of the mouse brain. The findings, published in Nature, provide an unprecedented picture of how decisions take shape in the brain, from sensory perception to action and reward.

Dr. Paul Glimcher, chair of neuroscience and physiology at New York University, said, “This is going to go down in history as a major even. They have created the largest dataset anyone has ever imagined at this scale.”

From One Neuron To Hundreds Of Thousands: How Brain Works?

Traditionally, brain studies tracked single neurons which was a slow process yielding small datasets. The new work relied on Neuropixels probes that are advanced electrodes which record thousands of neurons simultaneously. In the experiments, mice manipulated a steering wheel to respond to visual cues on a screen, earning sugar water as a reward. As they made choices, the probes recorded neural activity.

The map showed electrical activity spreading across much of the brain, starting in visual-processing regions, extending through motor areas as the mice acted and surging again during the reward. Researchers also tested memory-based decisions by making visual cues faint, revealing how prior knowledge shaped outcomes.

Is This A New Model For Neuroscience?

Yes, the project, led by the International Brain Laboratory, marks a rare large-scale collaboration in biology with standardized methods and data-sharing across labs worldwide.

Alexandre Pouget of the University of Geneva said, “This is our ‘Sloan Digital Sky Survey for the brain’. We’re really hoping this will inspire other groups to adopt this kind of approach.”

The work challenges older models that suggested decision-making was confined to small clusters of neurons, instead showing activity sweeping across the brain in a coordinated network.

Researchers said that the map will guide more focused studies of complex behavior and could reshape understanding of how memory, expectation and perception combine in decision-making.

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