Signal coding in cockroach photoreceptors is tuned to dim environments
Signal coding in cockroach photoreceptors is tuned to dim environments
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DOI：
10.1152/jn.00588.2012
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发表时间：
2012-11-01
影响因子：
2.5
通讯作者：
Weckstrom, M.
中科院分区：
文献类型：
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作者：
Heimonen, K.;Immonen, E-V.;Weckstrom, M.
Heimonen K、Immonen E-V、Frolov RV、Salmela I、Juusola M、Vahasoyrinki M、Weckstrom M。蟑螂光感受器中的信号编码被调整到昏暗的环境。 J Neurophysiol 108: 2641-2652, 2012。首次发表于 2012 年 8 月 29 日； doi:10.1152/jn.00588.2012.-在昏暗的光线下，光子的缺乏通常会导致视力不佳。尽管如此，许多动物在昏暗的环境中表现出视觉引导的行为。我们使用细胞内和全细胞膜片钳记录研究了暗活性蟑螂（美洲大蠊）光感受器的信号传导特性，以确定它们是否表现出对黑暗的选择性功能适应。不出所料，暗适应光感受器对单光子产生大而缓慢的反应。然而，当光线适应时，光转导和非转导膜对白噪声 (WN) 调制刺激的响应仍然缓慢，转角频率类似于 20 Hz。这促进了光输入的时间整合并保持视觉的高灵敏度。动态的适应性变化仅限于昏暗的条件。从特征上看，对于强度 >1,000 光子/秒/光感受器，阶跃响应和频率响应实际上保持不变。光响应的信噪比 (SNR) 在频率下瞬时较高
Heimonen K, Immonen E-V, Frolov RV, Salmela I, Juusola M, Vahasoyrinki M, Weckstrom M. Signal coding in cockroach photoreceptors is tuned to dim environments. J Neurophysiol 108: 2641-2652, 2012. First published August 29, 2012; doi:10.1152/jn.00588.2012.-In dim light, scarcity of photons typically leads to poor vision. Nonetheless, many animals show visually guided behavior with dim environments. We investigated the signaling properties of photoreceptors of the dark active cockroach (Periplaneta americana) using intracellular and whole-cell patch-clamp recordings to determine whether they show selective functional adaptations to dark. Expectedly, dark-adapted photoreceptors generated large and slow responses to single photons. However, when light adapted, responses of both phototransduction and the nontransductive membrane to white noise (WN)-modulated stimuli remained slow with corner frequencies similar to 20 Hz. This promotes temporal integration of light inputs and maintains high sensitivity of vision. Adaptive changes in dynamics were limited to dim conditions. Characteristically, both step and frequency responses stayed effectively unchanged for intensities >1,000 photons/s/photoreceptor. A signal-to-noise ratio (SNR) of the light responses was transiently higher at frequencies