Department of Psychological and Brain Sciences, Indiana University, 1101 E 10th Street, Bloomington, IN 47405, USA.
Exp Brain Res. 2011 Sep;214(1):139-50. doi: 10.1007/s00221-011-2813-x. Epub 2011 Aug 10.
There is an ongoing debate as to whether a greater degree of sensory-motor control is required to maintain skills as humans progress to be septuagenarians. Here, we investigate the dependence of older participants upon vision to execute skilled prehension movements. In a first experiment, participants were required to place a small, round peg in one of three randomly cued holes. A mirror apparatus was used to create conditions where they could always see the target locations, but vision of their hand approaching the target could be removed, and we explored end position accuracy. In a second experiment, we examined the ability of participants to precisely control their grasp action under conditions where they could see the objects but not their hands completing the action. The results showed that in Experiment 1, the older adults undershot the target in their primary submovement and hence had to move further in their secondary movement to achieve their goal. In Experiment 2, the older adults spent longer in the final adjustment phase (a near zero velocity phase at the end of the reach) when vision of the hand was unavailable. These findings suggest that older adults are indeed more reliant on visual feedback than the young in tasks that require precise manual control, and this clarifies conflicting accounts in the prior literature.
关于随着人类年龄增长到 70 岁,是否需要更高程度的感觉运动控制来维持技能,目前仍存在争议。在这里,我们研究了老年人在执行熟练的抓握动作时对视觉的依赖程度。在第一个实验中,要求参与者将一个小的圆形销钉放入三个随机提示的孔中的一个中。使用镜子设备来创造这样的条件,即他们始终可以看到目标位置,但可以消除他们的手接近目标的视觉,并探索终点位置的准确性。在第二个实验中,我们研究了参与者在可以看到物体但无法看到手完成动作的情况下精确控制抓握动作的能力。结果表明,在实验 1 中,老年人在主要子运动中低于目标,因此必须在次要运动中移动更远才能达到目标。在实验 2 中,当无法看到手时,老年人在最终调整阶段(接近到达末端时的零速度阶段)花费的时间更长。这些发现表明,在需要精确手动控制的任务中,老年人确实比年轻人更依赖视觉反馈,这澄清了先前文献中的矛盾说法。