The motivation, control, and selection of actions comprising naturalistic behaviors remains a tantalizing but difficult field of study. Detailed and unbiased quantification is critical. Interpreting the positions of animals and their limbs can be useful in studying behavior, and significant recent advances have made this step straightforward (1, 2). However, body position alone does not provide a grasp of the dynamic range of naturalistic behaviors. Behavioral Segmentation of Open-field In DeepLabCut, or B-SOiD ("B-side"), is an unsupervised learning algorithm that serves to discover and classify behaviors that are not pre-defined by users. Our algorithm segregates statistically different, sub-second rodent behaviors with a single bottom-up perspective video camera. Upon DeepLabCut estimating the positions of 6 body parts (snout, the 4 paws, and the base of the tail), our software performs novel expectation maximization fitting of Gaussian mixture models on t-Distributed Stochastic Neighbor Embedding (t-SNE). The original features taken from dimensionally-reduced classes are then used build a multi-class support vector machine classifier that can decode millions of actions within seconds. We demonstrate that the highly reproducible, independently-classified behaviors can be used to extract kinematic parameters of individual actions as well as broader action sequences. This open-source platform enables the efficient study of the neural mechanisms of spontaneous behavior as well as the performance of disease-related behaviors that have been difficult to quantify, such as grooming and stride-length in Obsessive-Compulsive Disorder (OCD) and stroke research.
Behavioral Analysis | Open-field | DeepLabCut | Unsupervised LearningCorrespondence: eyttri@andrew.cmu.edu