Nourouzpour Nilufer, Salomonczyk Danielle, Cressman Erin K, Henriques Denise Y P
School of Kinesiology and Health Science, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada,
Exp Brain Res. 2015 Mar;233(3):1019-29. doi: 10.1007/s00221-014-4176-6. Epub 2014 Dec 24.
We have recently shown that visuomotor adaptation following reaches with a misaligned cursor not only induces changes in an individual's motor output, but their proprioceptive sense of hand position as well. Long-term changes are seen in motor adaptation; however, very little is known about the retention of changes in felt hand position. We sought to evaluate whether this recalibration in proprioception, following visuomotor adaptation, is sufficiently robust to be retained the following day (~24 h later), and if so, to determine its extent. Visuomotor adaptation was induced by having subjects perform reaches to visual targets using a cursor representing their unseen hand, which had been gradually rotated 45° counterclockwise. Motor adaptation and proprioceptive recalibration were determined by assessing subjects' reach aftereffects and changes in hand bias, respectively. We found that subjects adapted their reaches and recalibrated their sense of hand position following training with a misaligned cursor, as shown in Cressman and Henriques (J Neurophysiol 102:3505-3518, 2009). More importantly, subjects who showed proprioceptive recalibration in the direction of motor adaptation on Day 1 did retain changes in felt hand position and motor adaptation on Day 2. These findings suggest that in addition to motor changes, individuals are capable of retaining sensory changes in proprioception up to 24 h later.
我们最近发现，使用未对齐的光标进行伸手动作后的视觉运动适应不仅会引起个体运动输出的变化，还会改变其手部位置的本体感觉。运动适应中会出现长期变化；然而，对于手部位置感觉变化的保持情况却知之甚少。我们试图评估视觉运动适应后本体感觉的这种重新校准是否足够稳定，能够在第二天（约24小时后）仍得以保持，如果是这样，则确定其程度。视觉运动适应是通过让受试者使用代表其看不见的手的光标向视觉目标伸手来诱导的，该光标已逐渐逆时针旋转45°。运动适应和本体感觉重新校准分别通过评估受试者的伸手后效和手部偏差变化来确定。我们发现，如克雷斯曼和恩里克斯（《神经生理学杂志》102:3505 - 3518，2009年）所示，受试者在使用未对齐的光标训练后调整了伸手动作并重新校准了手部位置感觉。更重要的是，在第一天朝着运动适应方向表现出本体感觉重新校准的受试者在第二天确实保留了手部位置感觉和运动适应的变化。这些发现表明，除了运动变化外，个体能够在长达24小时后仍保留本体感觉的感觉变化。
