Cressman Erin K, Henriques Denise Y P
School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada;
Department of Psychology, York University, Toronto, Ontario, Canada; and School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
J Neurophysiol. 2015 Jul;114(1):354-65. doi: 10.1152/jn.00415.2014. Epub 2015 May 13.
Visuomotor learning results in changes in both motor and sensory systems (Cressman EK, Henriques DY. J Neurophysiol 102: 3505-3518, 2009), such that reaches are adapted and sense of felt hand position recalibrated after reaching with altered visual feedback of the hand. Moreover, visuomotor learning has been shown to generalize such that reach adaptation achieved at a trained target location can influence reaches to novel target directions (Krakauer JW, Pine ZM, Ghilardi MF, Ghez C. J Neurosci 20: 8916-8924, 2000). We looked to determine whether proprioceptive recalibration also generalizes to novel locations. Moreover, we looked to establish the relationship between reach adaptation and changes in sense of felt hand position by determining whether proprioceptive recalibration generalizes to novel targets in a similar manner as reach adaptation. On training trials, subjects reached to a single target with aligned or misaligned cursor-hand feedback, in which the cursor was either rotated or scaled in extent relative to hand movement. After reach training, subjects reached to the training target and novel targets (including targets from a second start position) without visual feedback to assess generalization of reach adaptation. Subjects then performed a proprioceptive estimation task, in which they indicated the position of their hand relative to visual reference markers placed at similar locations as the trained and novel reach targets. Results indicated that shifts in hand position generalized across novel locations, independent of reach adaptation. Thus these distinct sensory and motor generalization patterns suggest that reach adaptation and proprioceptive recalibration arise from independent error signals and that changes in one system cannot guide adjustments in the other.
视觉运动学习会导致运动和感觉系统都发生变化(克雷斯曼·E·K,恩里克斯·D·Y。《神经生理学杂志》102:3505 - 3518,2009年),即在用改变后的手部视觉反馈进行伸手动作后,伸手动作会得到调整,手部感觉位置也会重新校准。此外,视觉运动学习已被证明具有泛化性,即在经过训练的目标位置实现的伸手适应可以影响向新目标方向的伸手动作(克拉考尔·J·W,派恩·Z·M,吉拉尔迪·M·F,盖兹·C。《神经科学杂志》20:8916 - 8924,2000年)。我们试图确定本体感觉重新校准是否也能泛化到新位置。此外,我们试图通过确定本体感觉重新校准是否以与伸手适应类似的方式泛化到新目标,来建立伸手适应与手部感觉位置变化之间的关系。在训练试验中,受试者在光标 - 手部反馈对齐或不对齐的情况下伸手到单个目标,其中光标相对于手部运动在范围上要么旋转要么缩放。在伸手训练后,受试者在没有视觉反馈的情况下伸手到训练目标和新目标(包括来自第二个起始位置的目标),以评估伸手适应的泛化情况。然后受试者执行本体感觉估计任务,在该任务中,他们指出自己的手相对于放置在与训练和新伸手目标类似位置的视觉参考标记的位置。结果表明,手部位置的变化在新位置上具有泛化性,与伸手适应无关。因此,这些不同的感觉和运动泛化模式表明,伸手适应和本体感觉重新校准源自独立的误差信号,且一个系统的变化无法指导另一个系统的调整。