Mice are always in motion. Even if there’s no external motivation for their actions—like a cat lurking a few feet away—mice are constantly sweeping their whiskers back and forth, sniffing around their environment and grooming themselves.

These spontaneous actions light up neurons across many different regions of the brain, providing a neural representation of what the animal is doing moment-by-moment across the brain. But how the brain uses these persistent, widespread signals remains a mystery.

Now, Janelia scientists have developed a tool that could bring researchers one step closer to understanding these enigmatic brain-wide signals. The tool, known as Facemap, uses deep neural networks to relate information about a mouse’s eye, whisker, nose, and mouth movements to neural activity in the brain.

Here, a video of a mouse face has been edited to label 13 key points that correspond to different facial movements associated with individual spontaneous behaviors, like whisking, grooming and licking.

The team first developed a neural network-based model that could identify these key points on in videos of mouse faces collected in the lab under various experimental setups. They then developed another deep neural network-based model to correlate this key facial point data representing mouse movement to neural activity, allowing them to see how a mouse’s spontaneous behaviors drive neural activity in a particular brain region.

Credit: Syeda et al. DOI: 10.1038/s41593-023-01490-6.

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