High Speed Videographic Analysis of Limb Movements During Active Sleep In Infant Rats

Spontaneous motor activity, in the form of limb twitching, occurs during active sleep in infant rats. It has been suggested that these twitch movements contribute to sensory-motor development. However, no one has yet fully characterized the fine structure of these twitches or their development over time. Previous work in our laboratory has attempted to study twitching using standard video recording of rats at various ages. However, because these twitches occur rapidly and frequently, standard video is inadequate for capturing the smallest and most discrete movements. Therefore, we are currently using high-speed motion analysis to analyze individual twitches, frame-by-frame, at 250 frames per second. By investigating the pattern and frequency of these movements across early development, we hope to learn more about the development of twitching and, ultimately, the neural control of twitching. To analyze this data, we devised a coding system that allows us to categorize distal and proximal limb movements. Proximal movements include movements of the shoulder and elbow, whereas distal movements include movements of the radial-ulnar joint, wrist, and digits. After we have established methods for scoring and analyzing twitches in developing rats, we plan to perform brain lesions to determine the neural control of proximal and distal limb twitches.