title: Model-independent phenotyping of C. elegans locomotion using scale-invariant feature transform.
abstract: To uncover the genetic basis of behavioral traits in the model organism C. elegans, a common strategy is to study locomotion defects in mutants. Despite efforts to introduce (semi-)automated phenotyping strategies, current methods overwhelmingly depend on worm-specific features that must be hand-crafted and as such are not generalizable for phenotyping motility in other animal models. Hence, there is an ongoing need for robust algorithms that can automatically analyze and classify motility phenotypes quantitatively. To this end, we have developed a fully-automated approach to characterize C. elegans' phenotypes that does not require the definition of nematode-specific features. Rather, we make use of the popular computer vision Scale-Invariant Feature Transform (SIFT) from which we construct histograms of commonly-observed SIFT features to represent nematode motility. We first evaluated our method on a synthetic dataset simulating a range of nematode crawling gaits. Next, we evaluated our algorithm on two distinct datasets of crawling C. elegans with mutants affecting neuromuscular structure and function. Not only is our algorithm able to detect differences between strains, results capture similarities in locomotory phenotypes that lead to clustering that is consistent with expectations based on genetic relationships. Our proposed approach generalizes directly and should be applicable to other animal models. Such applicability holds promise for computational ethology as more groups collect high-resolution image data of animal behavior.
authors: Department of Biomedical Engineering, Technion-Israel Institute of Technology, Israel.
authors: Yelena
authors: Y
authors: Koren
authors: Ophthalmic Technology Group, ARTORG Center, University of Bern, Switzerland.
authors: Raphael
authors: R
authors: Sznitman
authors: Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia PA, USA.
authors: Paulo E
authors: PE
authors: Arratia
authors: Department of Biomedical Sciences, West Virginia School of Osteopathic Medicine, Lewisburg WV, USA.
authors: Christopher
authors: C
authors: Carls
authors: Department of Biomedical Sciences, West Virginia School of Osteopathic Medicine, Lewisburg WV, USA.
authors: Predrag
authors: P
authors: Krajacic
authors: MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, UK.
authors: André E X
authors: AE
authors: Brown
authors: Department of Biomedical Engineering, Technion-Israel Institute of Technology, Israel.
authors: Josué
authors: J
authors: Sznitman
mesh_terms: D000465:Algorithms; D000818:Animals; D001696:Biomechanical Phenomena; D017173:Caenorhabditis elegans / Q000502:physiology*; D008124:Locomotion / Q000502:physiology*; D023421:Models, Animal; D010641:Phenotype