The supination assessment task: An automated method for quantifying forelimb rotational function in rats

Abstract

Background Neurological injuries or disease can impair the function of motor circuitry controlling forearm supination, and recovery is often limited. Preclinical animal models are essential tools for developing therapeutic interventions to improve motor function after neurological damage. Here we describe the supination assessment task, an automated measure of quantifying forelimb supination in the rat. New Method Animals were trained to reach out of a slot in a cage, grasp a spherical manipulandum, and supinate the forelimb. The angle of the manipulandum was measured using a rotary encoder. If the animal exceeded the predetermined turn angle, a reward pellet was delivered. This automated task provides a large, high-resolution dataset of turn angle over time. Multiple parameters can be measured including success rate, peak turn angle, turn velocity, area under the curve, and number of rotations per trial. The task provides a high degree of flexibility to the user, with both software and hardware parameters capable of being adjusted. Results We demonstrate the supination assessment task can effectively measure significant deficits in multiple parameters of rotational motor function for multiple weeks in two models of ischemic stroke. Comparison with Existing Methods Preexisting motor assays designed to measure forelimb supination in the rat require high-speed video analysis techniques. This operant task provides a high-resolution, quantitative end-point dataset of turn angle, which obviates the necessity of video analysis. Conclusions The supination assessment task represents a novel, efficient method of evaluating forelimb rotation and may help decrease the cost and time of running experiments.

The Knob Supination Task: A Semi-automated Method for Assessing Forelimb Function in Rats

“…Lastly, the supination task detects functional impairment after multiple types of injury, including a cut lesion of the corticospinal tract, the main pathway for voluntary movement in people, and forelimb motor cortex lesion performed with endothelin injections ( Figure 5 ) 8 10 22 . Rats in the pyramidotomy group (purple, n = 8) were trained to supinate at least 75° at 6 g at a success rate of 75% or above, while rats in the cortical lesion group (green, n = 10) were trained to supinate 60° at 7.5 g at 75% or above.…”

“…There are several advantages to automating tasks, namely objectivity, increased throughput, and decreased analysis time. New automated tasks provide a more sensitive measure of evaluating dexterity after injury than conventional tasks 8 10 . In addition, they allow for adaptive training and testing which tailors the training and testing difficulty to an animal's performance.…”

“…In addition, supination is highly sensitive to injury and inactivation, especially when compared to single pellet reaching 8 . The supination task, developed in a collaboration between the Burke Medical Research Institute and The University of Texas at Dallas, measures rotational movement in the horizontal plane 8 10 . Rats are placed in a behavioral box ( Figure 1A ) and are trained to do three movements ( Figure 1B ): reach through a rectangular aperture; grasp a spherical manipulandum; supinate to a designated angle.…”

Dexterity: A MATLAB-based analysis software suite for processing and visualizing data from tasks that measure arm or forelimb function

“…Below, Dexterity is described in the context of Vulintus’ MotoTrak system, specifically, the knob supination task (Meyers et al, 2016; Sindhurakar et al, 2016). Rats are placed into a reaching box, and the target of the reach is a knob that must be grasped and turned in supination to a success criterion (Figure 2F, “Supination”).…”

“…A. Hays et al, 2013; Meyers et al, 2016; Sindhurakar et al, 2016; Wong, Ramanathan, Gulati, Won, & Ganguly, 2015). Meanwhile, others have focused on automating arm and hand tests in humans (Bosecker, Dipietro, Volpe, & Krebs, 2010; Wikholm & Bohannon, 1991).…”