title: Bilateral alteration in stepping pattern after unilateral motor cortex injury: a new test strategy for analysis of skilled limb movements in neurological mouse models.
abstract: Mice are becoming increasingly popular to model neurological disease and motor system dysfunction. For evaluation of discrete, chronic motor impairments, skilled limb movements represent a valuable extension of standard mouse test batteries. This study introduces an efficient and sensitive test strategy for comprehensive assessment of skilled fore- and hind-limb stepping in mice. Adult C57BL/6 mice were trained and video-recorded in two walking tasks, the widely used rotorod test and a new ladder rung task. The animals then received a unilateral ischemic lesion in the motor cortex forelimb and hind limb area and were video-recorded on days 12 and 26 post-lesion. Forelimb and hind limb stepping movements were rated using a combination of endpoint measures and qualitative assessment. The results showed that while animals maintained a weight-supported gait, posture and stepping movements were abnormal at both post-operative intervals. The rotorod analysis revealed stepping deficits in both forelimbs that led to adoption of compensatory movement strategies. The ladder rung task revealed stepping errors in ipsi- and contralateral fore- and hind-limbs. The findings demonstrate that this test strategy provides comprehensive assessment of motor impairments in mice and that qualitative movement analysis is a valuable tool for elaborating subtle motor disturbances.
authors.affiliation: Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada. 0309845f@student.gla.ac.uk
authors.forename: Tracy D
authors.initials: TD
authors.lastname: Farr
authors.forename: Lily
authors.initials: L
authors.lastname: Liu
authors.forename: Keri L
authors.initials: KL
authors.lastname: Colwell
authors.forename: Ian Q
authors.initials: IQ
authors.lastname: Whishaw
authors.forename: Gerlinde A
authors.initials: GA
authors.lastname: Metz
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000145:classification / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D004195:Disease Models, Animal; D020233:Gait Disorders, Neurologic / Q000145:classification* / Q000175:diagnosis / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009048:Motor Skills; D009069:Movement Disorders / Q000145:classification / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D009422:Nervous System Diseases / Q000145:classification / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D045442:Rotarod Performance Test / Q000379:methods*; D012720:Severity of Illness Index; D013647:Task Performance and Analysis