THE SPATIAL INTEGRATION OF SIGNALS IN THE RETINA AND LAMINA OF THE FLY COMPOUND EYE UNDER DIFFERENT CONDITIONS OF LUMINANCE
THE SPATIAL INTEGRATION OF SIGNALS IN THE RETINA AND LAMINA OF THE FLY COMPOUND EYE UNDER DIFFERENT CONDITIONS OF LUMINANCE
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DOI：
10.1007/bf00612703
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发表时间：
1982-01-01
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影响因子：
--
通讯作者：
DUBS, A
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作者：
DUBS, A
用多种方法研究了受体细胞和1类一阶中间神经元的感受野。用细胞内法测定了家蝇、丝光绿蝇和柱花蝇的光感受器(R1-6)和1类一阶中间神经元(LMC)的空间调制传递函数(MTF)。使用25种不同空间频率的移动正弦波光栅来刺激细胞。通过逆傅立叶变换，计算出每个MTF对应的角灵敏度函数。所有电池对来自广角的光的敏感度都高于相同半宽的高斯电池的预期敏感度。当刺激光栅的平均光强和时间频率在有限的范围内变化时，受体细胞的角灵敏度函数没有明显的变化。当改变光栅的平均光强和时间频率时，LMC的MTF发生了显著的变化。计算的角敏感度函数在高平均强度和低时间频率下表现出抑制侧翼，在低平均强度和高时间频率时消失。用不同宽度的单棒测试受体和LMC的感受野。测量了S棒强度对正弦调制的响应作为棒宽度的函数。来自受体的结果证实了从MGF获得的场。当棒的宽度超过纯兴奋场(.apprx)时，二阶神经元的反应更加扭曲，幅度降低。3.学位。在L.cuprina)。利用这项技术，在不同的平均光强下，只检测到微小的差异。第一突触的传递函数在给波形增加一些失真的同时，也纠正了由于受体MTF引起的一些失真，即相对于平均强度的反应的调制不对称。测量了光感受器对轴上光源和离轴光源的脉冲响应函数。当光源主要刺激邻近感受器时，反应要慢得多，这表明不同光轴的感受器之间存在耦合。在刺激强度上也进行了相同的实验，受体耦合反映在类似的较慢反应中，与受体中观察到的一样。随着刺激强度的增加，侧向抑制降低了对离轴光的反应。三个点源被用来确定苍蝇叶片中的抑制是否反复出现。一个光点可以抑制另一个光点引发的反应，第三个光点不会减少这种抑制作用，这表明抑制不是反复发生的。
The receptive fields of receptor cells and 1 class of 1st order interneurons were investigated using several methods. The spatial modulation transfer function (MTF) was measured intracellularly from photoreceptors (R1-6) and 1 class of 1st order interneurons (LMC) [lamina monopolar cell] in the flies Musca domestica, Lucilia sericata and Calliphora stygia (R1-6; LMC). Moving sine wave gratings of 25 different spatial frequencies were used to stimulate the cells. The angular sensitivity function corresponding to each MTF was computed by taking the inverse Fourier transform. All cells have a higher sensitivity to light from wide angles than is expected of a Gaussian of the same half width. No significant changes in the angular sensitivity function of receptor cells are observed when the mean light intensity and the temporal frequency of the stimulus grating are varied within the limited range available. The LMC change their MTF significantly when the mean light intensity and the temporal frequency of the grating are altered. The computed angular sensitivity function exhibits inhibitory flanks at high mean intensity and low temporal frequency, which disappear at low mean intensity and high temporal frequency. The receptive fields of receptors and LMC were also tested using single bars of different widths. The response to sinusoidal modulation of the bar''s intensity was measured as a function of its width. The results from receptors confirm the fields obtained from the MGF. The responses of 2nd order neurons were more distorted and decreased in amplitude when the width of the bar exceeded the purely excitatory field (.apprx. 3.degree. in L. cuprina). With this technique, only small differences were detected between inhibitory effects at different mean light intensities. The transfer function of the 1st synapse, while adding some distortions to the waveform, also rectifies some of the distortions due to the receptor MTF, i.e., the modulation asymmetry with respect to the response to the mean intensity. The impulse response functions of photoreceptors to a light source positioned on-axis and off-axis were measured. A much slower response was obtained when the light source was stimulating mainly the neighboring receptors, suggesting coupling between receptors of different optical axis. Identical experiments were also carried out in the stimulus intensity, the receptor coupling is reflected in a similar slower response as observed in the receptors. With increasing stimulus intensity, lateral inhibition reduces the response to off-axis light. Three point sources were used to determine whether inhibition in the fly lamina is recurrent. One spot of light can inhibit the response invoked by another, a 3rd spot of light does not decrease this inhibitory effect suggesting that inhibition is not recurrent.