Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, NC 27599, USA.
Brain Res. 2011 Sep 30;1415:76-83. doi: 10.1016/j.brainres.2011.07.043. Epub 2011 Jul 27.
Adaptation has a pronounced impact on the perception of vibrotactile stimuli. Previously, we demonstrated that the duration of vibrotactile conditioning was directly proportional to the impact that adaptation has on sensory perception (Tannan et al., 2007b). Prior reports had proposed that the impact of adaptation on the perceived magnitude of vibrotactile stimuli was specific to the conditioning amplitude (Goble and Hollins, 1993), and this concept led us to hypothesize that if the amplitude of a vibrotactile stimulus was changed continuously, that this modulation would itself impact adaptation. In order to test this idea, two repetitive vibrotactile stimuli were simultaneously delivered to two adjacent finger tips (D2 and D3). In a matching task, a standard stimulus was maintained at constant amplitude (defined as "stationary"), while the amplitude of the test stimuli was increased at a fixed rate (i.e., 10 μm/s; defined as "non-stationary") from a null value up to the level that a subject (n=50) indicated that the two stimuli were perceived to be identical. Changing the standard amplitude yielded results consistent with Weber's Law and changing the modulation rate yielded results that were consistent with our initial hypothesis that faster modulation rates would lead to the non-stationary stimulus as being less adapted. A comparative study, using the above-described method, was conducted with 12 autism subjects who were previously reported to have below normal adaptation metrics (Tannan et al., 2008). The findings of this pilot autism study suggest that rate dependent modulation of vibrotactile stimuli could provide a more sensitive metric of adaptation, as the observations demonstrate a bimodal distribution within the autism spectrum.
适应对振动触觉刺激的感知有显著影响。之前，我们证明了振动触觉条件作用的持续时间与适应对感觉感知的影响成正比（Tannan 等人，2007b）。先前的报告提出，适应对振动触觉刺激感知幅度的影响特定于条件作用幅度（Goble 和 Hollins，1993），这一概念使我们假设如果振动触觉刺激的幅度连续变化，这种调制本身就会影响适应。为了验证这个想法，两个重复的振动触觉刺激同时施加到两个相邻的指尖（D2 和 D3）。在匹配任务中，标准刺激保持在恒定幅度（定义为“静止”），而测试刺激的幅度以固定速率（即 10 μm/s；定义为“非静止”）从零值增加到一个水平，即被测试者（n=50）表示两个刺激被感知为相同。改变标准幅度的结果与韦伯定律一致，而改变调制速率的结果与我们的初始假设一致，即更快的调制速率将导致非静止刺激适应程度较低。使用上述方法对 12 名自闭症受试者进行了一项比较研究，这些受试者之前的适应度指标低于正常水平（Tannan 等人，2008）。这项自闭症初步研究的结果表明，振动触觉刺激的速率依赖性调制可能提供一种更敏感的适应度指标，因为观察结果表明在自闭症谱内存在双峰分布。
