"Robot Assisted Brain-Wide Recordings in Freely Behaving Mice
Neuroscientists studying brain activity during behaviors usually have to make a trade-off: They use miniaturized head-mounted neural sensors that are light enough to allow a subject animal to behave freely, but are lower resolution or can’t monitor the whole brain. Or they use more powerful tools, which are far too heavy for subject animals and require other solutions, like immobilization while letting animals move on a treadmill, or even using virtual reality experiences that nonetheless limit the behavior of a subject.
Dr. Kodandaramaiah is tackling the challenge with a robotic cranial exoskeleton that carries the weight of neural recording and monitoring hardware while still allowing the subject (in this case a mouse) to rotate its head in all three degrees: a full 360 degree turn in the yaw (horizontal rotation) axis, and about 50 degrees of motion in the pitch and roll axes, while moving around in an arena. The robot has three jointed arms arranged in a triangular configuration, suspended over the subject and meeting at the point of mounting on the head. Sensors in the mount will detect what motion the mouse is making and direct the robot to enable the motion with as little resistive force as possible, allowing the mouse to turn and move within an arena typically used for neuroscience experiments with all the necessary sensory equipment and wires from the implants supported by the robot.
Taking out the need for miniaturization allows researchers to use whatever state-of-the art hardware is available, meaning a robot can theoretically be upgraded to use the latest technology soon after its introduction. To get to that point, Dr. Kodandaramaiah’s team will go through several steps – engineering the exoskeleton; engineering the head-stage with its needed sensors plus high-density electrodes and cameras for external observation of eyes, whiskers and more; performing benchtop testing; tuning the robot to the inputs a mouse can deliver; determining how to introduce probes; and finally making live recording. With this mechanical underpinning, Dr. Kodandaramaiah hopes to help researchers get closer to the state where they can make detailed brain-wide neural recordings of freely behaving subjects over long timescales."