Ilan Golani | Search bioRxiv

bioRxiv2016

Reproducibility and replicability of rodent phenotyping in preclinical studies

The scientific community is increasingly concerned with cases of published \"discoveries\" that are not replicated in further studies. The field of mouse behavioral phenotyping was one of the first to raise this concern, and to relate it to other complicated methodological issues: the complex interaction between genotype and environment; the definitions of behavioral constructs; and the use of the mouse as a model animal for human health and disease mechanisms. In January 2015, researchers from various disciplines including genetics, behavior genetics, neuroscience, ethology, statistics and bioinformatics gathered in Tel Aviv University to discuss these issues. The general consent presented here was that the issue is prevalent and of concern, and should be addressed at the statistical, methodological and policy levels, but is not so severe as to call into question the validity and the usefulness of model organisms as a whole. Well-organized community efforts, coupled with improved data and metadata sharing, were agreed by all to have a key role to play in identifying specific problems and promoting effective solutions. As replicability is related to validity and may also affect generalizability and translation of findings, the implications of the present discussion reach far beyond the issue of replicability of mouse phenotypes but may be highly relevant throughout biomedical research.

Scientific Communication and Education↗

bioRxiv2015

Shared generative rules of locomotor behavior in arthropods and vertebrates

The discovery of shared behavioral processes across phyla is an essential step in the establishment of a comparative study of behavior. We use immobility as an origin and reference for the measurement of locomotor behavior; speed, direction of walking and direction of facing as the three degrees of freedom shaping fly locomotor behavior; and cocaine as the parameter inducing a progressive transition in and out of immobility. In this way we expose and quantify the generative rules that shape part of fruit fly locomotor behavior, bringing about a gradual buildup of freedom during the transition from immobility to normal behavior and a precisely opposite narrowing down during the transition into immobility. During buildup the fly exhibits enhancement and then reduction to normal values of movement along each degree of freedom: first, body rotation in the horizontal plane, then path curvature and then speed of translation. Transition into immobility unfolds by narrowing down of the repertoire in the opposite sequential order, showing reciprocal relations during both buildup and narrowing down. The same generative rules apply to vertebrate locomotor behavior in a variety of contexts involving transition out and into immobility. Recent claims for deep homology between the arthropod central complex and the vertebrate basal ganglia provide an opportunity to examine whether the generative rules we discovered also share common descent. Neurochemical processes mediating the buildup of locomotor behavior in vertebrates could guide the search for equivalent processes in arthropods. The measurement methodology we use prompts the discovery of candidate behavioral homologies.\n\nSignificance StatementDo flies and mice share the same behavior? By defining immobility as an intrinsic reference point for locomotor behavior we show that the rules that generate the transition from immobility to full blown normal behavior, and from full blown behavior to immobility are shared by fruit flies and mice. These rules constitute a much desired aim of evolutionary biology: the discovery of behavioral homologies across distant phyla. The methodology we use facilitates the discovery of cross-phyletic behavioral homologies, shedding light on the problem of the evolution of behavior.

Animal Behavior and Cognition↗