Reaching and grasping phenotypes in the mouse (Mus musculus): A characterization of inbred strains and mutant lines

Skilled movements, such as reaching and grasping, have classically been considered as originating in the primate lineage. For this reason, the use of rodents to investigate the genetic and molecular machinery of reaching and grasping has been limited in research. A few studies in rodents have now shown that these movements are not exclusive to primates. Here we present a new test, the Mouse Reaching and Grasping (MoRaG) performance scale, intended to help researchers in the characterization of these motor behaviors in the mouse. Within the MoRaG test battery we identified early phenotypes for the characterization of motor neurone (Tg[SOD1-G93A]dl1Gur mice) and neurodegenerative (TgN(HD82Gln)81Dbo transgenic mice) disease models in addition to specific motor deficits associated with aging (C3H/HeH inbred strain). We conclude that the MoRaG test can be used to further investigate complex neuromuscular, neurological, neurodegenerative and behavioral disorders. Moreover, our study supports the validity of the mouse as a model for reaching and grasping studies.