Battery of Behavioral Tests Assessing General Locomotion, Muscular Strength, and Coordination in Mice

Summary

Behavioral testing is used in pre-clinical trials to assess the phenotypic effects of a disease or treatment on an animal's wellbeing. In order to globally assess motor functioning, we selected tests for general locomotion, muscular strength, and coordination: the open field test, the mesh test, and the rotarod test, respectively.

Abstract

Behavioral testing is used in pre-clinical trials to assess the phenotypic effects and outcomes that a particular disease or treatment has on the animal's wellbeing and health. There are numerous behavioral tests that may be applied. We selected a test for general locomotion, the open field test (OFT); a test for muscular strength, the mesh test (MT); and a test for coordination, the rotarod test (RR). Testing can be accomplished on a weekly or monthly basis. As a test for general locomotion, the OFT works by objectively monitoring movement parameters while the mouse is in an open field apparatus. The field is generally a 2' x 2' box, and the movements are recorded through laser sensing or through video capture. The mouse is placed in the center of the open field and allowed to move freely for the test. The MT uses the latency for a mouse to fall off an inverted screen as a measure of muscular strength. A mouse is placed on a screen, which is inverted over a clear box, and is timed for their latency to fall. Three trials are performed, with the best of the three trials scored for that day. A score of 60 s is the maximum time a mouse is left inverted. Mice are given a 5-min rest period between mesh test trials. Lastly, an accelerated protocol on the RR assesses motor coordination and endurance. During a trial, a mouse walks on a rotating rod as it increases in speed from 4 rpm to 40 rpm over 5 min. The trial ends when the mouse touches the magnetized pressure sensor upon falling. Each mouse undergoes three trials, and the best trial is scored for that day. This combined behavioral data allows for the global assessment of mobility, coordination, strength, and movement of the test animals. At least two out of the three behavioral testing measures must show improvement for an animal to qualify as having overall improved motor function.

Introduction

The goal of behavioral testing is to measure phenotypic characterization, whether in studies for a new mouse model of diseases affecting the central nervous system or for a trial of a new treatment. There are a variety of behavioral tests to choose from. The rationale for using a combination of behavioral tests is often to fully assess the pre-clinical treatment outcomes. The battery of behavioral testing herein includes the open field test (OFT), the mesh test (MT), and the rotarod test (RR).

The OFT is used as a measure of general locomotor activity^1,2,

Protocol

All protocols herein described were performed in accordance with, and were approved by, the Queen's University Animal Care Committee. The frequency of behavioral testing can be weekly or monthly, or a combination of the two (i.e., weekly when one expects to see the biggest difference, and monthly elsewhere).

NOTE: Murine behavioral studies are largely sex/age/strain- dependent, and therefore it is essential to collect the proper time points and to remain consistent across experimental groups. Environmental factors (e.g., scents, noise, temperature, humidity lighting, etc.) greatly affect behavior and anxiety i....

Results

The study animals may undergo the behavioral testing paradigm weekly or monthly to accommodate the necessary time points required for analysis. See Figure 1 for examples on behavioral testing timing. In the representative data below, taken from Osmon et al. (2016), the mice underwent the battery of behavioral testing monthly, beginning at 12 weeks of age, until their humane endpoint around 40 weeks of age. The timing of behavioral testing is sometimes critical fo.......

Discussion

For all tests, Clean and disinfect the surface to minimize contagions and distractors to the mice. Also, make certain that the mice are given sufficient rest periods between trials and between behavioral testing when using the OFT, RR, and MT.

In the OFT, it is critical that each mouse is placed in the middle of the open field and that the program is started upon the release of the mouse into the center. Be sure that there are no hand movements the sensors may register upon starting the p.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
IITC Life Sciences Rotarod with Series 8 computing software	IITC Life Sciences	755
Square Open Field 45 x 45 x 40 cm (grey color). Other floor color available: white, black.	Harvard Aparatus (PanLab)	760190
Open Field Preconfigured Module	Harvard Aparatus (PanLab)	760688
Smart V3.0 Software Platform	Harvard Aparatus (PanLab)	760681
Video converter (analog/digital)	Harvard Aparatus (PanLab)	760262
Roof fixing sys for camera	Harvard Aparatus (PanLab)	760277
Analog Sony Camera & lenseNTSC	Harvard Aparatus (PanLab)	760505