High-resolution in vivo kinematic tracking with customized injectable fluorescent nanoparticles

Area of Science:

• Neuroscience
• Biomedical Engineering
• Animal Behavior Analysis

Background:

• Markerless keypoint tracking in neuroscience enables movement quantification without surface markers.
• Current markerless methods lack the precision of human motion capture and require benchmarking in model organisms.
• Reliability of markerless systems for tracking movement kinematics is not fully established.

Purpose of the Study:

• To develop a precise and noninvasive method for tracking animal movement using injectable markers.
• To create a ground-truth dataset for training next-generation markerless tracking systems.
• To improve the understanding of how the brain controls skeletal movements.

Main Methods:

• Utilized near-infrared quantum dots as injectable markers for tracking.
• Demonstrated injection beneath skin or into joints for imaging in freely moving mice.
• Employed standard cameras for noninvasive, long-term imaging (months).

Main Results:

• Successfully tracked movement kinematics in mice using injectable quantum dots.
• Achieved noninvasive, long-term imaging of tagged animals.
• Developed a large ground-truth dataset for markerless system training.

Conclusions:

• Injectable quantum dots offer a precise alternative to markerless tracking for neuroscience.
• This method bridges the gap towards understanding brain-motor control of skeletal movements.
• The created dataset will facilitate advancements in markerless animal movement analysis.