IMR Press / JIN / Volume 20 / Issue 4 / DOI: 10.31083/j.jin2004096
Open Access Original Research
A parsimonious laboratory system for the evaluation of rat reaching task: recovery from the massive destruction of motor areas
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1 Department of Systems Life Engineering, Maebashi Institute of Technology, Kamisadori-machi, 371-0816 Maebashi, Gunma, Japan
2 Department of Technological ME Research and Development, TOP Co. Ltd., 120-0035 Tokyo, Japan
3 Department of Physical Therapy, Faculty of Health Care, Takasaki University of Health and Welfare, Nakaoruicho, 370-0033 Takasaki, Gunma, Japan
4 Accounting Affairs, Ono Sokki, Co. Ltd., 222-8507 Yokohama, Japan
*Correspondence: (Yoichi Ohno)
J. Integr. Neurosci. 2021, 20(4), 955–965;
Submitted: 16 August 2021 | Revised: 25 November 2021 | Accepted: 30 November 2021 | Published: 30 December 2021
Copyright: © 2021 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license (

The rat reaching task is one of the best paradigms from behavioral study of upper limb movements. Rats are trained to reach and grab a pellet by extending their hand through a vertical slit. A few conventional imaging systems specific for the rat reaching task are commercially available with a high installation cost. Based on image analysis of video recordings obtained during the reaching task, we, herewith, developed a new, low-cost laboratory system that can be used for the quantitative analysis of ten basic forearm movements, in contrast to subjective assessments used in previous studies. We quantified images of the pronated and supinated palm and the accuracy and speed of reaching the target. Applying this newly developed method, we compared the forearm movements during the reaching task before and after a massive anatomical lesion of the sensorimotor cortex performed by tissue aspiration. We also wanted to investigate the recovery of upper limb function possibly induced by repeating the task for a relatively short term of a few weeks. In the experiment, 7 injured groups and 3 control groups were used. We found characteristic abnormalities of the forearm movements and a significant recovery in the success rate of grasping the target pellet. The present results demonstrate that our method is straightforward for the quantitative evaluation of forearm movements during the reaching task primarily controlled by the sensorimotor cortex.

Reaching task
Forearm movement
Video image analysis
Sensorimotor cortex
Fig. 1.
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