Beyond cones: an improved model of whisker bending based on measured mechanics and tapering
Beyond cones: an improved model of whisker bending based on measured mechanics and tapering
复制标题
DOI：
10.1152/jn.00511.2015
复制
发表时间：
2016-08-01
影响因子：
2.5
通讯作者：
Golomb, David
中科院分区：
文献类型：
--
作者：
Hires, Samuel Andrew;Schuyler, Adam;Golomb, David
触觉由机械感觉输入力诱发的神经活动模式表示。啮齿类动物的触须系统在研究触觉的神经生理学方面是例外的，部分原因是这些力可以从触须变形的视频中精确计算出来。我们评估晶须弯曲的标准模型的准确性，假设准静态动力学和线性锥形轮廓，使用控制晶须偏转。我们发现模型和实验之间的显着差异：真实的晶须弯曲超过预测后，在中间的位置接触的晶须和远端位置少。因此，晶须的行为，如果他们的刚度附近的基地和附近的尖端是大于预期的一个均匀的圆锥。我们评估是否接触方向，摩擦，不均匀的弹性，晶须取向，或非圆锥形形状可以解释这些偏差。我们发现，一个薄的中间锥度的鼠标胡须形状占了大部分的这种行为。这种锥度在晶须阵列的行和列上是守恒的。锥度有很大的影响，触摸诱发的力量和容易与胡须滑过去的对象，这是关键的驱动程序的神经活动，在触觉对象定位和识别。这适用于具有指向、远离或向下指向物体的固有触须曲率的方向，验证了简单触须-物体相互作用的二维模型。计算模型的精度相关的感觉输入力的神经活动模式，可以定量地提高薄中锥考虑一个简单的校正函数，我们提供。
The sense of touch is represented by neural activity patterns evoked by mechanosensory input forces. The rodent whisker system is exceptional for studying the neurophysiology of touch in part because these forces can be precisely computed from video of whisker deformation. We evaluate the accuracy of a standard model of whisker bending, which assumes quasi-static dynamics and a linearly tapered conical profile, using controlled whisker deflections. We find significant discrepancies between model and experiment: real whiskers bend more than predicted upon contact at locations in the middle of the whisker and less at distal locations. Thus whiskers behave as if their stiffness near the base and near the tip is larger than expected for a homogeneous cone. We assess whether contact direction, friction, inhomogeneous elasticity, whisker orientation, or nonconical shape could explain these deviations. We show that a thin-middle taper of mouse whisker shape accounts for the majority of this behavior. This taper is conserved across rows and columns of the whisker array. The taper has a large effect on the touch-evoked forces and the ease with which whiskers slip past objects, which are key drivers of neural activity in tactile object localization and identification. This holds for orientations with intrinsic whisker curvature pointed toward, away from, or down from objects, validating two-dimensional models of simple whisker-object interactions. The precision of computational models relating sensory input forces to neural activity patterns can be quantitatively enhanced by taking thin-middle taper into account with a simple corrective function that we provide.