title: Statistical Analysis of Zebrafish Locomotor Response.
abstract: Zebrafish larvae display rich locomotor behaviour upon external stimulation. The movement can be simultaneously tracked from many larvae arranged in multi-well plates. The resulting time-series locomotor data have been used to reveal new insights into neurobiology and pharmacology. However, the data are of large scale, and the corresponding locomotor behavior is affected by multiple factors. These issues pose a statistical challenge for comparing larval activities. To address this gap, this study has analyzed a visually-driven locomotor behaviour named the visual motor response (VMR) by the Hotelling's T-squared test. This test is congruent with comparing locomotor profiles from a time period. Different wild-type (WT) strains were compared using the test, which shows that they responded differently to light change at different developmental stages. The performance of this test was evaluated by a power analysis, which shows that the test was sensitive for detecting differences between experimental groups with sample numbers that were commonly used in various studies. In addition, this study investigated the effects of various factors that might affect the VMR by multivariate analysis of variance (MANOVA). The results indicate that the larval activity was generally affected by stage, light stimulus, their interaction, and location in the plate. Nonetheless, different factors affected larval activity differently over time, as indicated by a dynamical analysis of the activity at each second. Intriguingly, this analysis also shows that biological and technical repeats had negligible effect on larval activity. This finding is consistent with that from the Hotelling's T-squared test, and suggests that experimental repeats can be combined to enhance statistical power. Together, these investigations have established a statistical framework for analyzing VMR data, a framework that should be generally applicable to other locomotor data with similar structure.
authors.affiliation: Department of Statistics, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America; Department of Statistics, Purdue University, West Lafayette, Indiana, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Carmer
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America.
authors.forename: Gaonan
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America.
authors.forename: Prahatha
authors.initials: P
authors.lastname: Venkatraman
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America.
authors.forename: Skye Ashton
authors.initials: SA
authors.lastname: Brown
authors.affiliation: Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Chi-Pui
authors.initials: CP
authors.lastname: Pang
authors.affiliation: Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong, Shantou, China.
authors.forename: Mingzhi
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Statistics, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Ping
authors.initials: P
authors.lastname: Ma
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine Lafayette, West Lafayette, Indiana, United States of America.
authors.forename: Yuk Fai
authors.initials: YF
authors.lastname: Leung
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000528:radiation effects; D005260:Female; D008027:Light; D008297:Male; D008954:Models, Biological; D010775:Photic Stimulation; D013550:Swimming; D015027:Zebrafish / Q000196:embryology / Q000254:growth & development / Q000502:physiology*