Naveed, M. | bioRxiv Science

bioRxiv2023

Lights, Camera, Mirrors, Action! Toolbox for 3D Reconstruction and Analysis Using a Single Camera and Planar Mirrors

The advent of high-speed cameras being made available for commercial use has facilitated the discovery of intriguing animal behaviors. However, analyzing animal kinematics in three dimensions necessitates using several high-speed cameras, which are specialized equipment and come at a significant expense. In this study, we utilize a conventional methodology of capturing synchronized multiple views using a solitary camera and planar mirrors. We introduce a user-friendly software package that facilitates the calibration of this economical setup and enables the three-dimensional (3D) analysis of high-rate maneuvers. Within[~] 15 minutes, a single high-speed camera is calibrated and can be used to acquire 3D data. We accompany the toolbox with a detailed user guide and video tutorial (https://tinyurl.com/yckm9y6b) for ease of use. We accurately reconstruct the wing beats of multiple flies (dragonfly, butterfly).

animal behavior and cognition↗

bioRxiv2022

Cardiac electrophysiological remodeling associated with enhanced arrhythmia susceptibility in a canine model of elite exercise

The health benefits of regular physical exercise are well known. Even so, there is increasing evidence that the exercise regimes of elite athletes can evoke cardiac arrhythmias including ventricular fibrillation and even sudden cardiac death (SCD). The mechanism of exercise-induced arrhythmia and SCD is poorly understood. While some studies after endurance training have been performed in small animals these have limited translation value. Here, we show that chronic training in a canine model (12 sedentary and 12 trained dogs) that mimics the regime of elite athletes induces electrophysiological remodeling (measured by ECG, patch-clamp and immunocytochemical techniques) resulting in increases of both the trigger and the substrate for ventricular arrhythmias. Thus, 4 months sustained training lengthened ventricular repolarization (QTc: 213.6{+/-}2.8 ms vs. 237.1{+/-}3.4 ms, n=12; APD90: 370.1{+/-}32.7 ms vs. 472.8{+/-}29.6 ms, n=25 vs. 29), decreased transient outward potassium current (8.8{+/-}0.9 pA/pF vs. 6.4{+/-}0.5 pA/pF at 50 mV, n=42 vs. 54) and increased the short term variability of repolarization (17.5{+/-}4.0 ms vs. 29.5{+/-}3.8 ms, n=18 vs. 27). Left ventricular fibrosis and HCN4 protein expression were also enhanced. These changes were associated with enhanced ectopic activity (number of extrasystoles: 4/hour vs. 366/hour) in vivo and arrhythmia susceptibility (elicited ventricular fibrillation: 3 of 10 sedentary dogs vs. 6 of 10 trained dogs). Our findings provide in vivo, cellular electrophysiological and molecular biological evidence for the enhanced susceptibility to ventricular arrhythmia in an experimental large animal model of endurance training.

physiology↗