Wright Rachel L, Elliott Mark T
School of Psychology, College of Life and Environmental Sciences, University of Birmingham Edgbaston, Birmingham, UK.
Front Hum Neurosci. 2014 Sep 11;8:724. doi: 10.3389/fnhum.2014.00724. eCollection 2014.
Humans can synchronize movements with auditory beats or rhythms without apparent effort. This ability to entrain to the beat is considered automatic, such that any perturbations are corrected for, even if the perturbation was not consciously noted. Temporal correction of upper limb (e.g., finger tapping) and lower limb (e.g., stepping) movements to a phase perturbed auditory beat usually results in individuals being back in phase after just a few beats. When a metronome is presented in more than one sensory modality, a multisensory advantage is observed, with reduced temporal variability in finger tapping movements compared to unimodal conditions. Here, we investigate synchronization of lower limb movements (stepping in place) to auditory, visual and combined auditory-visual (AV) metronome cues. In addition, we compare movement corrections to phase advance and phase delay perturbations in the metronome for the three sensory modality conditions. We hypothesized that, as with upper limb movements, there would be a multisensory advantage, with stepping variability being lowest in the bimodal condition. As such, we further expected correction to the phase perturbation to be quickest in the bimodal condition. Our results revealed lower variability in the asynchronies between foot strikes and the metronome beats in the bimodal condition, compared to unimodal conditions. However, while participants corrected substantially quicker to perturbations in auditory compared to visual metronomes, there was no multisensory advantage in the phase correction task-correction under the bimodal condition was almost identical to the auditory-only (AO) condition. On the whole, we noted that corrections in the stepping task were smaller than those previously reported for finger tapping studies. We conclude that temporal corrections are not only affected by the reliability of the sensory information, but also the complexity of the movement itself.
人类能够毫不费力地将动作与听觉节拍或节奏同步。这种跟上节拍的能力被认为是自动的，以至于即使没有有意识地注意到干扰，也能对任何干扰进行校正。上肢（如手指敲击）和下肢（如踏步）动作对相位受扰听觉节拍的时间校正通常会使个体在仅仅几下节拍后就回到同步状态。当节拍器以不止一种感觉模态呈现时，会观察到多感觉优势，与单模态条件相比，手指敲击动作的时间变异性降低。在这里，我们研究下肢动作（原地踏步）与听觉、视觉以及听觉 - 视觉（AV）组合节拍器提示的同步情况。此外，我们比较了在三种感觉模态条件下，针对节拍器的相位提前和相位延迟干扰的动作校正情况。我们假设，与上肢动作一样，会存在多感觉优势，即在双模态条件下踏步变异性最低。因此，我们进一步预期在双模态条件下对相位干扰的校正会最快。我们的结果显示，与单模态条件相比，双模态条件下脚步击打与节拍器节拍之间的异步性变异性更低。然而，虽然与视觉节拍器相比，参与者对听觉节拍器干扰的校正要快得多，但在相位校正任务中并没有多感觉优势——双模态条件下的校正几乎与仅听觉（AO）条件相同。总体而言，我们注意到踏步任务中的校正比之前手指敲击研究报告的要小。我们得出结论，时间校正不仅受感觉信息可靠性的影响，还受动作本身复杂性的影响。
