The representation of stimulus orientation in the early stages of somatosensory processing
The representation of stimulus orientation in the early stages of somatosensory processing
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DOI：
10.1523/jneurosci.4162-07.2008
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发表时间：
2008-01-16
影响因子：
5.3
通讯作者：
Hsiao, Steven S.
中科院分区：
文献类型：
--
作者：
Bensmaia, Sliman J.;Denchev, Peter V.;Hsiao, Steven S.
在处理的早期阶段，刺激被表示为一组轮廓。在形式的表示中，这些局部轮廓的一个关键特征是它们的方向。在本研究中，我们研究了体感外围和初级体感皮层的方向表征。我们使用各种刺激条件记录了区域 3b 和 1 中的机械感受传入神经元和神经元对定向条和边缘的反应。我们发现，方向在单个传入神经的响应中没有明确表示，但在区域 3b 和 1 中可以找到很大一部分方向检测器（类似于 50%）。这两个区域中的许多神经元都表现出方向调整，该调整在刺激呈现模式（扫描与缩进）中得以保留，并且对其他刺激参数（例如幅度和速度）以及刺激的性质相对不敏感。 刺激、条或边缘。方向选择性神经元往往更像 SA（缓慢适应）而不是 RA（快速适应），并且方向信号的强度在对静态锯齿状条的响应的持续部分期间最强。 SI 中最具方向选择性的神经元的灵敏度与人类测量的灵敏度相当。最后，可以使用高斯或 Gabor 滤波器对 SI 神经元对条和边缘的响应进行高精度建模。视觉和体感系统中方向表征的相似性表明，类似的神经机制介导早期视觉和触觉形式处理。
At an early stage of processing, a stimulus is represented as a set of contours. In the representation of form, a critical feature of these local contours is their orientation. In the present study, we investigate the representation of orientation at the somatosensory periphery and in primary somatosensory cortex. We record the responses of mechanoreceptive afferents and of neurons in areas 3b and 1 to oriented bars and edges using a variety of stimulus conditions. We find that orientation is not explicitly represented in the responses of single afferents, but a large proportion of orientation detectors (similar to 50%) can be found in areas 3b and 1. Many neurons in both areas exhibit orientation tuning that is preserved across modes of stimulus presentation (scanned vs indented) and is relatively insensitive to other stimulus parameters, such as amplitude and speed, and to the nature of the stimulus, bar or edge. Orientation-selective neurons tend to be more SA (slowly adapting)-like than RA(rapidly adapting)-like, and the strength of the orientation signal is strongest during the sustained portion of the response to a statically indented bar. The most orientation-selective neurons in SI are comparable in sensitivity with that measured in humans. Finally, responses of SI neurons to bars and edges can be modeled with a high degree of accuracy using Gaussian or Gabor filters. The similarity in the representations of orientation in the visual and somatosensory systems suggests that analogous neural mechanisms mediate early visual and tactile form processing.