Overview

• Two companion Nature papers published on September 3 map brain activity during a visual choice task and detail brain-wide representations of prior information.
• The dataset spans 621,733 neurons recorded with 699 Neuropixels probes across 279 regions in 139 mice, covering about 95% of the mouse brain.
• Analyses show decision-related signals are distributed across tens of areas rather than localized, with activity building before movement and reflecting upcoming choices.
• Prior expectations influenced neural activity throughout the brain, including early sensory relays such as the thalamus, with subjective priors encoded across 20–30% of regions.
• All data, tools, and protocols are publicly accessible, and IBL presents this release as a starting point for broader research and potential insights into disorders such as schizophrenia and autism.