Support for the slip hypothesis from whisker-related tactile perception of rats in a noisy environment.
Support for the slip hypothesis from whisker-related tactile perception of rats in a noisy environment.
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DOI：
10.3389/fnint.2015.00053
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发表时间：
2015
影响因子：
3.5
通讯作者：
Schwarz C
中科院分区：
文献类型：
--
作者：
Waiblinger C;Brugger D;Whitmire CJ;Stanley GB;Schwarz C
啮齿动物使用活跃的胡须运动来探索它们的环境。胡须相关触觉感知的“滑动假设”需要短暂的运动学事件（突然的胡须运动，称为“滑动”，由于在纹理的主动触摸期间发生的生物弹性胡须特性）携带决定性的纹理信息。支持这一假设，以前的研究表明，滑移幅度和频率发生在纹理依赖的方式。此外，采用被动脉动触须偏转的实验表明，基于脉冲运动学的感知性能（即，类似滑动的信号）远上级基于时间积分变量（如频率和强度）的信号。到目前为止，脉动刺激是在无噪声环境中使用的。然而，现实场景涉及背景噪声（例如，通过摩擦纹理引起）。因此，如果滑动用于触觉感知，触觉神经元系统将需要区分滑动诱发的尖峰与噪声诱发的尖峰。为了在这些更真实的条件下测试动物，我们向头部固定的训练大鼠呈现被动胡须偏转，包括嵌入背景噪声中的“类滑动”事件（波形模仿触摸真实的纹理时发生的滑动）。改变（i）形状（斜坡或脉冲）;（ii）运动学（幅度、速度等）;及（iii）类滑脱事件发生的概率，我们观察到大鼠可以很容易地检测到不同形状的类滑脱事件对嘈杂的背景。心理物理学曲线显示，滑动事件和噪声幅度的差异决定了知觉，而发生概率（频率）的增加几乎没有任何影响。这些结果强烈支持的概念，编码的运动学主要决定胡须相关的触觉感知，而计算的频率或强度起着次要的作用。
Rodents use active whisker movements to explore their environment. The “slip hypothesis” of whisker-related tactile perception entails that short-lived kinematic events (abrupt whisker movements, called “slips”, due to bioelastic whisker properties that occur during active touch of textures) carry the decisive texture information. Supporting this hypothesis, previous studies have shown that slip amplitude and frequency occur in a texture-dependent way. Further, experiments employing passive pulsatile whisker deflections revealed that perceptual performance based on pulse kinematics (i.e., signatures that resemble slips) is far superior to the one based on time-integrated variables like frequency and intensity. So far, pulsatile stimuli were employed in a noise free environment. However, the realistic scenario involves background noise (e.g., evoked by rubbing across the texture). Therefore, if slips are used for tactile perception, the tactile neuronal system would need to differentiate slip-evoked spikes from those evoked by noise. To test the animals under these more realistic conditions, we presented passive whisker-deflections to head-fixed trained rats, consisting of “slip-like” events (waveforms mimicking slips occurring with touch of real textures) embedded into background noise. Varying the (i) shapes (ramp or pulse); (ii) kinematics (amplitude, velocity, etc.); and (iii) the probabilities of occurrence of slip-like events, we observed that rats could readily detect slip-like events of different shapes against noisy background. Psychophysical curves revealed that the difference of slip event and noise amplitude determined perception, while increased probability of occurrence (frequency) had barely any effect. These results strongly support the notion that encoding of kinematics dominantly determines whisker-related tactile perception while the computation of frequency or intensity plays a minor role.