Background

The cylinder test measures the rodent's spontaneous forelimb use, which can be used to evaluate the sensory-motor function in a number of injury models that cause forelimb use asymmetry (Schallert et al., 2000). In this test, the mouse is placed in a glass cylinder and the number of times it rears up and touches the cylinder wall is measured. The wall touches are subsequently scored for the left, right, or both paws by an observer in slow motion recorded videos. The results are expressed as the percentage of each paw usage relative to the total number of touches.

The cylinder test is a common behavioral assessment used to evaluate the motor impairments in experimental models of Parkinson’s disease. Our laboratory and others have previously shown that mice with unilateral injection of 6-OHDA in the striatum, substantia nigra pars compacta or medial forebrain bundle exhibit a remarkable forelimb asymmetry due to lesion of the nigrostriatal pathway (Iancu et al., 2005; Kriks et al., 2011; Subramaniam et al., 2011; Boix et al., 2015; Chu et al., 2017; Magno et al., 2019). While a healthy mouse uses the right and the left paw indifferently, dopamine-lesioned mice show preferential use of the paw ipsilateral to the lesion (Figure 1).

The cylinder test can be used to evaluate the preclinical screening of antiparkinsonian therapeutic interventions based on the functional recovery of the contralateral paw (Kriks et al., 2011; Francardo et al., 2014; Fischer et al., 2017; Magno et al., 2019). A number of other unilateral experimental models of neurological disorder including spinal cord injury and cerebral ischemia have been shown to be sensitive to the degree of forelimb asymmetry measured in the cylinder test (Schallert et al., 2000; Starkey et al., 2005; Venna et al., 2014; Wang et al., 2015; Warren et al., 2018; Carballo-Carbajal et al., 2019).

The cylinder test has been found to be easy to perform and sensitive to detect motor impairments that other behavioral tests fail to detect. On the other hand, analysis of the videotape records are time-consuming, and the test cannot be repeated frequently as mice will lose interest in exploring the vertical surface of the cylinder (Lundblad et al., 2002).