Mizunami M, Tateda H, Naka K
J Gen Physiol. 1986 Aug;88(2):275-92. doi: 10.1085/jgp.88.2.275.
The incremental responses from the second-order neurons of the ocellus of the cockroach, Periplaneta americana, have been measured. The stimulus was a white-noise-modulated light with various mean illuminances. The kernels, obtained by cross-correlating the white-noise input against the resulting response, provided a measure of incremental sensitivity as well as of response dynamics. We found that the incremental sensitivity of the second-order neurons was an exact Weber-Fechner function; white-noise-evoked responses from second-order neurons were linear; the dynamics of second-order neurons remain unchanged over a mean illuminance range of 4 log units; the small nonlinearity in the response of the second-order neuron was a simple amplitude compression; and the correlation between the white-noise input and spike discharges of the second-order neurons produced a first-order kernel similar to that of the cell's slow potential. We conclude that signal processing in the cockroach ocellus is simple but different from that in other visual systems, including vertebrate retinas and insect compound eyes, in which the system's dynamics depend on the mean illuminance.
已测量了美洲大蠊单眼二阶神经元的增量反应。刺激是具有各种平均照度的白噪声调制光。通过将白噪声输入与所得反应进行互相关得到的核，提供了增量敏感性以及反应动力学的度量。我们发现二阶神经元的增量敏感性是精确的韦伯 - 费希纳函数；二阶神经元的白噪声诱发反应是线性的；二阶神经元的动力学在4个对数单位的平均照度范围内保持不变；二阶神经元反应中的小非线性是简单的幅度压缩；并且白噪声输入与二阶神经元的脉冲放电之间的相关性产生了类似于细胞慢电位的一阶核。我们得出结论，蟑螂单眼的信号处理很简单，但与其他视觉系统不同，包括脊椎动物视网膜和昆虫复眼，在这些系统中，系统的动力学取决于平均照度。
