Head-mounted robot allows mice to be tracked while moving

The new development could forever change how we study the animals.
Loukia Papadopoulos
The mice were tracked in a maze.jpg
The mice were tracked in a maze.


A new robotic headgear allows mice to move freely while being attached to heavy and cumbersome brain-recording machinery, allowing scientists to track their brain activity in motion, according to a new report by Spectrum published on Thursday. The development could have major implications in neuropathy and other sciences of the brain.

Under normal circumstances, researchers analyze brain activity in an awake mouse by fixing the animal’s head in a stiff unmovable position beneath a microscope. This however severely limits the mouse’s range of motion and therefore does not produce accurate results.

As Ted Abel, chair of neuroscience and pharmacology at the University of Iowa in Iowa City, who was not involved in the study, explained to Spectrum, this approach is not conducive to usable outcomes.

 “The vestibular system and interoception are important for navigation, and these sensations don’t show up if the head is fixed,” Abel explained.

Cranial exoskeleton

The new robotic headgear is referred to as a “cranial exoskeleton” and consists of a three-armed robot that senses the animal’s movement and moves with it, allowing researchers to investigate brain activity in detail as a mouse moves freely and interacts with its natural environment.

“This strikes me as a real advance,” Abel told Spectrum. It’s “getting closer to naturalistic behaviors, enabling us to understand how the brain responds to the environment and how animals learn to navigate the environment.”

In tests conducted and reported in a preprint paper, the researchers made use of a 3D-printed implant that went directly into a mouse’s brain, connecting the organ to the robotic headgear.

The robot was programmed to move at the same speed as the rodent and to report the data it collects from this movement. The researchers reported that the mice followed in the experiment were able to steer the exoskeleton around corners in a maze and undertake decision-making tasks. They did this as efficiently as unrestricted animals indicating the robotic headgear had no impact on a mouse’s natural ability to move.

Piloting the robot

Once the researchers were reassured that the mice could pilot the robot, they proceeded to attach to the headgear a custom-built microscope designed to image large swathes of the brain. They modified the mouse’s neurons to fluoresce when triggered by calcium signals and inserted a glass window into the skull of each mouse to better image their brain activity. This resulted in a map of the firing patterns of thousands of neurons across the mouse’s cortex. 

Spectrum specified that the work was led by Suhasa Kodandaramaiah at the University of Minnesota in Minneapolis, who declined to comment because the work is unpublished.