Department of Systems and Computational Neurobiology, Max-Planck-Institute of Neurobiology, 82152 Martinsried, Germany.
Neuron. 2011 Jun 23;70(6):1155-64. doi: 10.1016/j.neuron.2011.03.028.
Recent experiments have shown that motion detection in Drosophila starts with splitting the visual input into two parallel channels encoding brightness increments (ON) or decrements (OFF). This suggests the existence of either two (ON-ON, OFF-OFF) or four (for all pairwise interactions) separate motion detectors. To decide between these possibilities, we stimulated flies using sequences of ON and OFF brightness pulses while recording from motion-sensitive tangential cells. We found direction-selective responses to sequences of same sign (ON-ON, OFF-OFF), but not of opposite sign (ON-OFF, OFF-ON), refuting the existence of four separate detectors. Based on further measurements, we propose a model that reproduces a variety of additional experimental data sets, including ones that were previously interpreted as support for four separate detectors. Our experiments and the derived model mark an important step in guiding further dissection of the fly motion detection circuit.
最近的实验表明，果蝇的运动检测始于将视觉输入分为两个平行通道，分别编码亮度增加（ON）或减少（OFF）。这表明存在两种（ON-ON、OFF-OFF）或四种（用于所有成对交互）独立的运动检测器。为了在这些可能性之间做出决定，我们使用 ON 和 OFF 亮度脉冲序列刺激苍蝇，同时记录来自运动敏感切线细胞的信号。我们发现对相同信号（ON-ON、OFF-OFF）的序列有方向选择性反应，但对相反信号（ON-OFF、OFF-ON）的序列没有反应，从而否定了存在四种独立检测器的可能性。基于进一步的测量，我们提出了一个模型，可以重现各种额外的实验数据集，包括之前被解释为支持四种独立检测器的数据集。我们的实验和得出的模型标志着在指导进一步剖析苍蝇运动检测电路方面迈出了重要的一步。
