人为何有指纹【转自生物谷】

据1月30日的《科学》杂志内法国的研究人员报告说，除了帮助人们抓住东西之外，我们指尖的皮肤纹脊还能帮助我们感受精细的质地以及某一表面的极小的物体。以往的研究已经显示，这一感觉精细特质的能力（即分辨不到200微米的宽度，大约相当于一根人类毛发的宽度）涉及在我们的手指细察某一表面时皮肤的振动。

为了研究这些振动是如何转化为一种实际的感觉，Julien Schiebert 及其同僚研发出了一种覆盖了一个可延展的弹性盖帽的力学传感器，该弹性盖帽可以像我们的指尖那样呈平滑或是脊状的隆起。当该“指纹化的”传感器对多种图案化的表面进行摩擦时，摩擦所产生的振动的频率与某种被称作“帕氏小体”（Pacinian corpuscles）的皮肤神经末梢所能察觉的频率一样。这些小体与感觉神经元相连，而其一旦激活的话会给脑部发出信号。（人们已知帕氏小体与感觉精细质地有关。而感受粗糙质地的是另外一种类型的神经末梢。）研究人员报告说，那些指纹化的表面（但不是平滑的表面）看来能够放大及过滤某种振动频率，使得神经系统能够探测到该信号。（生物谷Bioon.com）

生物谷推荐原始出处：

Science Published Online January 29, 2009 DOI: 10.1126/science.1166467

The Role of Fingerprints in the Coding of Tactile Information Probed with a Biomimetic Sensor

J. Scheibert 1, S. Leurent 1, A. Prevost 1, G. Debrégeas 1*

1 Laboratoire de Physique Statistique de l'ENS, UMR 8550, CNRS–ENS–Université Paris 6 & Paris 7, 24 rue Lhomond F–75231 Paris, France.

In humans, the tactile perception of fine textures (spatial scale <200 μm) is mediated by skin vibrations generated as the finger scans the surface. To establish the relationship between texture characteristics and subcutaneous vibrations, a biomimetic tactile sensor has been designed whose dimensions match those of the fingertip. When the sensor surface is patterned with parallel ridges mimicking the fingerprints, the spectrum of vibrations elicited by randomly textured substrates is dominated by one frequency set by the ratio of the scanning speed to the inter-ridge distance. For human touch, this frequency falls within the optimal range of sensitivity of Pacinian afferents which mediate the coding of fine textures. Thus, fingerprints may perform spectral selection and amplification of tactile information that facilitate its processing by specific mechanoreceptors.