Velocity invariance of receptive field structure in somatosensory cortical area 3b of the alert monkey
Velocity invariance of receptive field structure in somatosensory cortical area 3b of the alert monkey
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DOI：
10.1523/jneurosci.19-01-00401.1999
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发表时间：
1999-01-01
影响因子：
5.3
通讯作者：
Johnson, KO
中科院分区：
文献类型：
--
作者：
DiCarlo, JJ;Johnson, KO
这是关于警觉猴子大脑皮层3b区触觉空间形式的神经表征的系列研究中的第二项。我们先前研究了指垫上330区3b神经元感受野(RF)的空间结构，以一种速度扫描随机点图案(40毫米/秒；DiCarlo等人，1998)。在这里，我们通过研究在三种扫描速度(20、40和80 mm/s)下的84个神经元RF的空间结构来分析它们的时间结构。与以前的研究一样，大多数RFs包含一个单一的中央兴奋区和一个或多个周围或侧翼的抑制区。皮肤刺激至兴奋作用的平均时延为15.5毫秒，除平均速率不同外，各神经元的反应及其射频的空间结构基本不受扫描速度的影响。当兴奋和抑制效应是短暂和同步的时，这是预期的结果。然而，这种解释既不符合已报道的躯体感觉皮层兴奋和抑制的时间，也不符合本系列中的第三项研究，该研究调查了扫描方向的影响，并表明抑制的一个成分落后于激发。我们通过证明相对于激发延迟的重叠(场内)抑制可以产生不受扫描速度变化影响的RF空间结构来协调这些观察结果。不管是什么机制？区域3b射频结构的速度不变性与触觉空间知觉(如粗糙度估计和形状识别)的速度不变性是一致的。
This is the second in a series of studies of the neural representation of tactile spatial form in cortical area 3b of the alert monkey. We previously studied the spatial structure of 330 area 3b neuronal receptive fields (RFs) on the fingerpad with random dot patterns scanned at one velocity (40 mm/sec; DiCarlo et al., 1998). Here, we analyze the temporal structure of 84 neuronal RFs by studying their spatial structure at three scanning velocities (20, 40, and 80 mm/sec). As in the previous study, most RFs contained a single, central, excitatory region and one or more surrounding or flanking inhibitory regions. The mean time delay between skin stimulation and its excitatory effect was 15.5 msec, Except for differences in mean rate, each neuron's response and the spatial structure of its RF were essentially unaffected by scanning velocity. This is the expected outcome when excitatory and inhibitory effects are brief and synchronous. However, that interpretation is consistent neither with the reported timing of excitation and inhibition in somatosensory cortex nor with the third study in this series, which investigates the effect of scanning direction and shows that one component of inhibition lags behind excitation. We reconcile these observations by showing that overlapping (in-field) inhibition delayed relative to excitation can produce RF spatial structure that is unaffected by changes in scanning velocity. Regardless of the mechanisms? the velocity invariance of area 3b RF structure is consistent with the velocity invariance of tactile spatial perception (e.g., roughness estimation and form recognition).