Organization of the reach and grasp in head-fixed vs freely-moving mice provides support for multiple motor channel theory of neocortical organization.
Multiple motor channel (MMC) theory of neocortical organization proposes that complex movements, such as reaching for a food item to eat, are produced by the coordinated action of separate neural channels. For example, the human reach-to-grasp act is mediated by two visuo-parieto-motor cortex channels, one for the reach and one for the grasp. The present analysis asked whether there is a similar organization of reach-and-grasp movements in the mouse. The reach-to-eat movements of the same mice were examined from high-shutter speed, frame-by-frame video analysis in three tasks in which the mice obtained equivalent success scores: when freely-moving reaching for food pellets, when head-fixed reaching for food pellets, and when head-fixed reaching for pieces of pasta. To reach, the mice used egocentric cues to vary upper arm movements in a task-appropriate manner to place an open hand on the food or to locate the food using a "touch-release-grasp" strategy. Although mice could not hand-shape offline when reaching, they could hand-shape using online touch-related cues from the mouth to manipulate the food at the mouth. That the reach can be performed offline in relation to egocentric cues whereas hand shaping for the grasp requires online cues supports the idea that for the mouse, as for primates, the reach and grasp are separate acts. The results are further discussed in relation to the use of the head-fixed behavioral procedure to identify the independent neural substrates of the reach and the grasp using mesoscale stimulation/imaging methods.
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada. Whishaw@uleth.ca.
Ian Q
IQ
Whishaw
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.|Faculty of Nursing and Midwifery, Golestan University of Medical Sciences, Gorgan, Islamic Republic of Iran.
Jamshid
J
Faraji
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
Jessica
J
Kuntz
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
Behroo
B
Mirza Agha
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
Mukt
M
Patel
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
Gerlinde A S
GAS
Metz
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada. mohajerani@uleth.ca.
Majid H
MH
Mohajerani
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D006257:Head; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000502:physiology*; D019579:Neocortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*
Head-fixing and reaching; Independent reach and grasp in mice; Multiple channel organization of mouse reaching