Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA.
J Biomech. 2011 Nov 10;44(16):2775-81. doi: 10.1016/j.jbiomech.2011.08.027. Epub 2011 Oct 11.
Rats use specialized tactile hairs on their snout, called vibrissae (whiskers), to explore their surroundings. Vibrissae have no sensors along their length, but instead transmit mechanical information to receptors embedded in the follicle at the vibrissa base. The transmission of mechanical information along the vibrissa, and thus the tactile information ultimately received by the nervous system, depends critically on the mechanical properties of the vibrissa. In particular, transmission depends on the bending stiffness of the vibrissa, defined as the product of the area moment of inertia and Young's modulus. To date, Young's modulus of the rat vibrissa has not been measured in a uniaxial tensile test. We performed tensile tests on 22 vibrissae cut into two halves: a tip-segment and a base-segment. The average Young's modulus across all segments was 3.34±1.48GPa. The average modulus of a tip-segment was 3.96±1.60GPa, and the average modulus of a base-segment was 2.90±1.25GPa. Thus, on average, tip-segments had a higher Young's modulus than base-segments. High-resolution images of vibrissae were taken to seek structural correlates of this trend. The fraction of the cross-sectional area occupied by the vibrissa cuticle was found to increase along the vibrissa length, and may be responsible for the increase in Young's modulus near the tip.
老鼠利用其鼻子上特化的触觉毛发（触须）来探索周围环境。触须本身没有传感器，而是将机械信息传递到触须基部毛囊中的受体。机械信息沿着触须的传递，以及最终由神经系统接收的触觉信息，都取决于触须的机械特性。特别是，传递取决于触须的弯曲刚度，其定义为惯性矩和杨氏模量的乘积。迄今为止，尚未在单轴拉伸试验中测量过大鼠触须的杨氏模量。我们对 22 根切成两半的触须进行了拉伸试验：一个是尖端段，另一个是基部段。所有段的平均杨氏模量为 3.34±1.48GPa。尖端段的平均模量为 3.96±1.60GPa，基部段的平均模量为 2.90±1.25GPa。因此，平均而言，尖端段的杨氏模量高于基部段。我们拍摄了触须的高分辨率图像，以寻找这种趋势的结构相关性。发现触须角质层占据的横截面面积分数沿着触须长度增加，这可能是尖端附近杨氏模量增加的原因。
