Fukuda Shiho, Gao Han, Hamada Naoki, Hiraoka Koichi
School of Rehabilitation Science, Graduate School of Osaka Metropolitan University, 3-7-30 Habikino, Habikino 583-8555, Osaka, Japan.
School of Medicine, Osaka Metropolitan University, 3-7-30 Habikino, Habikino 583-8555, Osaka, Japan.
Brain Sci. 2025 Apr 20;15(4):422. doi: 10.3390/brainsci15040422.
: When manipulating an object placed on the palm, the eyes and fingers move together. To perform this task precisely, coordination of the eyes and fingers is needed. Based on this view, the present study examined the three-way interaction among the central motor drives to the eyes, index finger, and little finger. : Healthy male participants abducted the right index and/or little finger with or without concomitant saccadic eye movement to the right in response to a visual cue, while the forearm was in the pronated or supinated position. We measured the reaction time (RT), velocity, and amplitude of the eye movements, as well as the RT and amplitude of the electromyographic (EMG) responses in the prime movers for the independent and dependent finger movements. : The velocity, amplitude, and RT of the eye movement were not changed by the additional involvement of the finger movement, indicating that the central motor drive to the finger does not influence the eye motor excitability and central motor drive to the eyes. On the one hand, the RT of the finger was not changed by the eye movement, indicating that the central motor drive to the eyes does not influence the central motor drive to the finger muscle. On the other hand, the EMG amplitude in the first dorsal interosseous muscle at the movement onset decreased during the concomitant eye movement, indicating that the central motor drive to the eyes suppresses the motor excitability of the independent finger muscle. The RT increased and EMG amplitude decreased in one finger muscle when the other finger concurrently moved, indicating that the central motor drive to one finger muscle suppresses the motor excitability of and central motor drive to the other finger muscle. The change in the RT and EMG amplitude in one finger muscle caused by the concomitant execution of the other finger movement and/or eye movement varied with forearm position, indicating that forearm proprioception influences the interaction of the motor execution processes among the fingers and eyes. : The central motor drive to the eyes or finger muscles suppresses the motor excitability of the other finger muscles and the central motor drive to that muscle, but the central motor drive to the finger muscles does not influence those for the eyes. Forearm proprioception influences the motor excitability of the finger muscle and central motor drive to that muscle.
当操作放置在手掌上的物体时，眼睛和手指会一起移动。为了精确执行此任务，需要眼睛和手指的协调配合。基于这一观点，本研究考察了对眼睛、食指和小指的中枢运动驱动之间的三向相互作用。健康男性参与者在视觉提示下，在手臂处于旋前或旋后位置时，伴随或不伴随向右的眼球跳动，外展右手食指和/或小指。我们测量了眼球运动的反应时间（RT）、速度和幅度，以及独立和相关手指运动的原动肌中肌电图（EMG）反应的RT和幅度。手指运动的额外参与并未改变眼球运动的速度、幅度和RT，这表明对手指的中枢运动驱动不会影响眼球运动的兴奋性和对眼睛的中枢运动驱动。一方面，眼球运动并未改变手指的RT，这表明对眼睛的中枢运动驱动不会影响对手指肌肉的中枢运动驱动。另一方面，在伴随眼球运动期间，运动开始时第一背侧骨间肌的EMG幅度降低，这表明对眼睛的中枢运动驱动会抑制独立手指肌肉的运动兴奋性。当另一根手指同时移动时，一根手指肌肉的RT增加而EMG幅度降低，这表明对一根手指肌肉的中枢运动驱动会抑制另一根手指肌肉的运动兴奋性和对该肌肉的中枢运动驱动。由另一根手指运动和/或眼球运动的同时执行引起的一根手指肌肉的RT和EMG幅度变化随前臂位置而变化，这表明前臂本体感觉会影响手指和眼睛之间运动执行过程的相互作用。对眼睛或手指肌肉的中枢运动驱动会抑制其他手指肌肉的运动兴奋性和对该肌肉的中枢运动驱动，但对手指肌肉的中枢运动驱动不会影响对眼睛的中枢运动驱动。前臂本体感觉会影响手指肌肉的运动兴奋性和对该肌肉的中枢运动驱动。
