How Global Teams Charted the First Brain-Wide Map of Decision-Making in Mice

If we could observe an entire brain as it navigates rapid-fire choices, what would insights would it reveal? Thanks to an unprecedented international collaboration we are getting closer to an answer. 

Scientists have now mapped decision-making across the entire mouse brain at single-cell resolution, offering fresh insights and challenging long-standing views about how our brains function.

Uniting Minds: The Power of Collaboration

Traditional neuroscience often focused on small brain regions, missing the bigger picture. To address this, 22 labs from Europe and the U.S., under the International Brain Laboratory (IBL), banded together. Their mission: capture and analyze brain activity across nearly the whole mouse brain during decision-making tasks.

The Princeton teams of Ilana Witten, Tatiana Engel, and Jonathan Pillow played a central role. They standardized experiments and integrated massive data streams, resulting in a dataset that includes recordings from more than 620,000 neurons in 139 mice spanning 279 distinct brain regions.

Cutting-Edge Experimental Design

Mice were trained to use miniature steering wheels, moving visual targets on a screen to earn sweet rewards. Some tasks were straightforward, but others required memory and anticipation, providing a unique window into how experience informs choices.

• High-density electrodes enabled simultaneous tracking of hundreds of neurons across multiple brain regions.
  
  
• Each lab contributed by focusing on specific brain areas for a truly comprehensive map.
  
  
• Standardized methods allowed seamless pooling and analysis of data on a scale never before seen.

Findings: A Distributed Network for Decisions

The resulting map upended old beliefs. Decision-making signals were found not just in classic cognitive centers but also in motor regions, suggesting the whole brain participates in choice. This distributed activity highlights the intricate web of connections that underlie even simple decisions.

Importantly, the entire dataset is now open to the scientific community, with hopes of spurring new discoveries and innovative models of how brains make decisions.

Collaboration as a Blueprint for Science

This project isn’t just about the data it’s a proof of concept for large-scale, coordinated science. Uniting 22 labs took rigorous planning and shared standards, paving the way for future global efforts in neuroscience and beyond. As Tatiana Engel put it, this is “a beginning, not the grand finale.”

Takeaway: A New Standard for Brain Research

The first brain-wide, single-cell map of decision-making in mice is a game-changer. It reveals the brain’s deep interconnectedness and sets a new bar for collaborative science. With open data and global teamwork, the stage is set for breakthroughs in understanding the brain—and behavior for years to come.

Source:

Princeton Neuroscience Institute Blog, “First brain-wide map of decision-making charted in mice,” September 3, 2025. Original Source