This project addresses a central challenge in neuroscience: understanding how distributed brain regions integrate sensory input, prior expectations, and motor planning to drive behavior. To overcome the limitations of fragmented experimental approaches, the IBL coordinated a large-scale, standardized effort across 12 laboratories, recording from 139 mice performing a unified decision-making task. Using 699 Neuropixels probe insertions, neural activity was captured across 241 brain areas spanning the forebrain, midbrain, hindbrain, and cerebellum.

This unprecedented dataset enables a comprehensive appraisal of brain-wide activity during decision making, revealing broad and overlapping representations of stimuli, movement, and reward throughout the brain. The dataset also captures more selective encoding of prior expectations in specific regions. By making this data openly available, along with standardized preprocessing pipelines and metadata, the project provides an essential technical resource for the field, allowing researchers to explore distributed neural computations with consistency and reproducibility. This effort sets a new standard for collaborative, scalable neuroscience.