SIMULATION OF MOTION ON THE SKIN .1. RECEPTIVE-FIELDS AND TEMPORAL FREQUENCY CODING BY CUTANEOUS MECHANORECEPTORS OF OPTACON PULSES DELIVERED TO THE HAND
SIMULATION OF MOTION ON THE SKIN .1. RECEPTIVE-FIELDS AND TEMPORAL FREQUENCY CODING BY CUTANEOUS MECHANORECEPTORS OF OPTACON PULSES DELIVERED TO THE HAND
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DOI：
10.1152/jn.1989.62.6.1410
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发表时间：
1989-12-01
影响因子：
2.5
通讯作者：
PALMER, CI
中科院分区：
文献类型：
--
作者：
GARDNER, EP;PALMER, CI
1. 形式的触觉辨别需要手在扫描的物体上移动。为了将皮肤的横向变形与涉及多个受体类别和并行中央网络的神经元处理机制分离，我们通过使用计算机控制的顺序激活探针网格（OPTACON 刺激器）模拟了手指和手掌上的条形图案的运动。水平条图案以 30-120 毫米/秒的速度扫过手，以定量表征正中神经和尺神经中记录的皮肤机械感受传入的反应。 2. 对压力有阶段性反应的机械感受器由 OPTACON 上的空间模式激活，而对强直压力反应的机械感受器则不会；移动条模式强烈激发迈斯纳传入神经[快速适应（RA）机械感受器]和帕西尼小体（PC），但无法激发慢速适应（SA）传入神经。因此，OPTACON 型刺激器允许通过空间复杂的刺激选择性激活相位机械感受器通道。 3. RA 传入神经对手指上 1-5 毫米跨度的两到五个相邻行的激活以全有或全无的方式做出反应，在所有试验中具有几乎相同的延迟；反应概况因其规律性和可重复性而引人注目。与 RA 相比，PC 具有更大的视野（4-13 行）和更强但更不规则的响应。 4. 整个感受野的均匀敏感性是 RA 反应的一致特征。在 75% 的 RA 测试中，各个机械感受器终端似乎对尖峰起始区具有相同的访问权限，并提供相同的振幅输入，因为光纤在每个场位置处放电 1 个尖峰/脉冲。均匀的灵敏度允许每个传入信号传输感兴趣参数的重复信号，例如物体速度、轮廓或纹理。 5. 四分之一的 RA 会发射两个尖峰来探测现场中心的压痕和缩回。这种分级反应通常仅在一个运动方向上观察到，反映了受体激活的首选顺序，而不是皮肤上的特定位置。 PC 在其大部分感受野中发射两到四个尖峰；敏感性分布广泛，而不是达到峰值。因此，相位机械感受器无法提供刺激位置的精确信号；单个乳头脊水平的定位似乎是由涉及 RA、SA 和 PC 传入的独特组合的群体机制发出的信号。（摘要截断为 250 字）
1. Tactile discrimination of form requires motion of the hand across the object scanned. To dissociate lateral distortion of the skin from neuronal processing mechanisms involving multiple receptor classes and parallel central networks, we have simulated motion of bar patterns across the fingers and palm by the use of a computer-controlled grid of sequentially activated probes (OPTACON stimulator). Horizontal bar patterns have been swept across the hand at speeds of 30-120 mm/s to quantitatively characterize responses of cutaneous mechanoreceptive afferents recorded in the median and ulnar nerves. 2. Mechanoreceptors with phasic responses to pressure are activated by spatial patterns on the OPTACON, whereas those with tonic pressure responses are not; moving-bar patterns strongly excite both Meissner's afferents [rapidly adapting (RA) mechanoreceptors] and Pacinian corpuscles (PCs) but fail to excite slowly adapting (SA) afferents. OPTACON-type stimulators thus allow selective activation of phasic mechanoreceptor channels with spatially complex stimuli. 3. RA afferents respond in an all-or-none fashion to activation of two to five adjacent rows spanning 1-5 mm on the finger, with nearly identical latencies on all trials; response profiles are remarkable for their regularity and reproducibility. PCs have larger fields (4-13 rows) and stronger but more irregular responses than RAs. 4. Uniform sensitivity throughout the receptive field is a consistent feature of RA responses. Individual mechanoreceptor terminals appear to have equal access to the spike initiation zone and provide the same amplitude input as the fiber discharges 1 spike/pulse at each field location in 75% of the RAs tested. Uniform sensitivity allows each afferent to transmit a repetitive signal of the parameter of interest such as object speed, contour, or texture. 5. One-quarter of RAs fire two spikes to probe indentation and retraction at the field center. Such graded responses are usually observed in only one direction of motion, reflecting a preferred sequence of receptor activation rather than a specific location on the skin. PCs fire bursts of two to four spikes throughout most of their receptive fields; sensitivity is broadly distributed rather than peaked. Thus phasic mechanoreceptors fail to provide a precise signal of stimulus location; localization at the level of individual papillary ridges appears to be signaled by a population mechanism involving unique combinations of RA, SA, and PC afferents.(ABSTRACT TRUNCATED AT 250 WORDS)