Morioka Miyuki, Griffin Michael J
Human Factors Research Unit, Institute of Sound and Vibration Research, University of Southampton, Southampton, UK.
Somatosens Mot Res. 2005 Dec;22(4):281-97. doi: 10.1080/08990220500420400.
The detection of vibration applied to the glabrous skin of the hand varies with contact conditions. Three experiments have been conducted to relate variations in the perception of hand-transmitted vibration to previously reported properties of tactile channels. The effects of a surround around the area of contact, the size of the area of contact, the location of the area of contact, the contact force, and the hand posture on perception of thresholds were determined for 8-500 Hz vibration. Removal of a surround around a contact area on the fingertip elevated thresholds of the NP II channel (FA I fibres) at frequencies less than 31.5 Hz and reduced thresholds of the Pacinian channel (FA II fibres) at frequencies greater than about 63 Hz. When no surround was present, thresholds reduced systematically as the contact area increased from the fingertip to the whole hand at frequencies from 16 to 125 Hz, although the decrease was not inversely proportional to the increase in contact area. The results are partly explained by spatial summation in the Pacinian channel (FA II fibres) and the involvement of the NP II channel (SA II) with some influence of biodynamic responses and contact pressures. There were regional differences in sensitivity over the hand within the NP I channel but not within the Pacinian channel: the NP I thresholds (less than 31.5 Hz) decreased from proximal to distal regions of the hand, whereas the Pacinian thresholds (125 Hz) were independent of contact location over the hand.
施加于手部无毛皮肤的振动检测会因接触条件而有所不同。已进行了三项实验，以将手部传递振动的感知变化与先前报道的触觉通道特性联系起来。针对8 - 500赫兹的振动，确定了接触区域周围的环绕物、接触区域的大小、接触区域的位置、接触力以及手部姿势对阈值感知的影响。去除指尖接触区域周围的环绕物会提高频率低于31.5赫兹时NP II通道（FA I纤维）的阈值，并降低频率高于约63赫兹时帕西尼小体通道（FA II纤维）的阈值。当不存在环绕物时，在16至125赫兹的频率下，随着接触区域从指尖增加到整个手部，阈值会系统性降低，尽管这种降低与接触区域的增加并非成反比。这些结果部分可通过帕西尼小体通道（FA II纤维）中的空间总和以及NP II通道（SA II）的参与来解释，同时生物动力学反应和接触压力也有一定影响。在NP I通道内，手部各区域的敏感性存在差异，但在帕西尼小体通道内则不存在：NP I阈值（低于31.5赫兹）从手部近端向远端区域降低，而帕西尼小体阈值（125赫兹）与手部接触位置无关。
