SPATIAL AND TEMPORAL CONTRAST SENSITIVITIES OF NEURONS IN LATERAL GENICULATE-NUCLEUS OF MACAQUE
SPATIAL AND TEMPORAL CONTRAST SENSITIVITIES OF NEURONS IN LATERAL GENICULATE-NUCLEUS OF MACAQUE
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DOI：
10.1113/jphysiol.1984.sp015498
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发表时间：
1984-01-01
影响因子：
5.5
通讯作者：
LENNIE, P
中科院分区：
文献类型：
--
作者：
DERRINGTON, AM;LENNIE, P
本文报道了猕猴外侧膝状体小细胞层和大细胞层单个神经元的放电。用玻璃绝缘钨微电极记录。使用Hochstein和Shapley设计的检验检查空间总和的线性。小细胞单位（2/272）和6/105大细胞单位显示出明显的非线性空间总和。非线性的定量指标并不表明存在一个独特的非线性类的magnocellular单位。空间对比敏感度移动光栅测量的跟踪程序中，对比度进行了调整，以引起一个可靠的调制放电。除了蓝色敏感锥驱动的细胞，对比敏感度的测量没有发现不同的小细胞单位亚组。所有人的敏感度都很低，那些感受野位于中央凹的人可以分辨高达40个周期度的空间频率。大细胞单位有更高的灵敏度，但较差的空间分辨率。大细胞单位的高灵敏度导致它们对高对比度刺激的饱和反应。小细胞单位的反应很少饱和的任何刺激。在任何1偏心，小细胞单位的感受野有较小的中心比大细胞单位。同侧眼驱动的大细胞单位的感受野比对侧眼驱动的感受野大。小细胞单位是最敏感的刺激调制在接近10 Hz的时间频率;大细胞单位是最敏感的刺激调制在接近20 Hz的频率。灵敏度的损失，时间频率低于最佳，是更显着的大细胞比小细胞单位。时间频率的变化改变了小细胞和大细胞单位的空间对比敏感度曲线的形状。这些变化可以通过假设中心和环绕具有不同的时间特性并且环绕对较高的时间频率相对较不敏感来解释。
The discharges of single neurons in the parvocellular and magnocellular laminae of the macaque''s [Macaca fascicularis, Macaca mulatta] lateral geniculate nucleus (l.g.n.) were recorded with glass-insulated tungsten micro-electrodes. Linearity of spatial summation was examined using the test devised by Hochstein and Shapley. Parvocellular units (2 of 272)and 6 of 105 magnocellular units showed clearly non-linear spatial summation. A quantitative index of non-linearity did not suggest the the existence of a distinct non-linear class of magnocellular unit. Spatial contrast sensitivity to moving gratings was measured by a tracking procedure in which contrast was adjusted to elicit a reliable modulation of discharge. With the exception of cells that were driven by blue-sensitive cones, measurements of contrast sensitivity did not reveal distinct subgroups of parvocellular units. All had low sensitivity, and those with receptive fields in the fovea could resolve spatial frequencies of up to 40 cycles deg-1 [degree]. Magnocellular units had substantially higher sensitivity, but poorer spatial resolution. The higher sensitivities of magnocellular units led to their giving saturated responses to stimuli of high contrast. Responses of parvocellular units were rarely saturated by any stimulus. At any 1 eccentricity, the receptive fields of parvocellular units had smaller centers than did those of magnocellular units. Receptive fields of magnocellular units driven by the ipsilateral eye had larger receptive fields than did those driven by the contralateral eye. Parvocellular units were most sensitive to stimuli modulated at temporal frequencies close to 10 Hz; magnocellular units were most sensitive to stimuli modulated at frequencies nearer 20 Hz. The loss of sensitivity, as temporal frequency fell below optimum, was more marked in magnocellular than parvocellular units. Changes in temporal frequency altered the shapes of the spatial contrast sensitivity curves of both parvocellular and magnocellular units. These changes could be explained by supposing that center and surround have different temporal properties and that the surround is relatively less sensitive to higher temporal frequencies.