日常中光源的差異性其實是很大的，較高階的動物具有瞳孔及水晶體能調節光源進入的量，再經由光受器(photoreceptor)後端的神經及腦區調節使生物在視覺下不會因光源差異而失真。希望了解生物是如何調節光源以確保影像不因光源差異而失真，而使用果蠅為研究對象，果蠅視覺因沒有瞳孔調節入射光，是光線直接進入光受器傳到光髓質(Optic Medulla/Med)後再傳至下游腦區，且果蠅光源視覺的處理方式僅是由位於 Med 內的局部神經元(Local neuron/LN)調節。由之前的研究發現位於 Med 中的 LN 有大小上的差異，且皆為抑制型神經元。因此我們設
計多種覆蓋範圍的 LN，希望找到這些型態上差異的功能。
而此篇實驗的結果是發現型態與外在刺激的關連性及覆蓋範圍的大小具有調
控上功能，能將高刺激區塊調節與低刺激區塊相近且能將於高刺激區塊中的細節明顯。功能類似相機系統中的高動態範圍成像(HDR)技術

Animals are able to perceive detailed visual features in natural scene, which often
exhibits high contrast ratio across the field of view. Although being a fundamental
feature of the visual system, the circuit mechanism of the high dynamic range is not
well understood. To address the problem, we developed a computational model of the
local neuron (M6LN) circuit in the sixth layers of the medulla, a neuropil in the early
visual area. A recent study revealed that the M6LNs have diverse coverage patterns in
the medulla and suggested that M6LNs may take part in tuning the dynamic range of the
visual system.
1
We systematically investigated the correlation between the coverage
patterns of M6LNs and ability of dynamic range tuning. We tested our model with
images of natural scene and found that the combination of N6LNs with specific
coverage patterns led to the optimal results. Under this circuit configuration, the visual
system is able to process images with high contrast ratio in a way similar to the
high-dynamic rang (HDR) technique used in modern cameras.

簡介 . 1
工具與方法 . 4
一、 Flysim： . 4
二、 神經網路：. 4
三、 圖像刺激：. 5
四、 工具方程式：. 6
五、 實驗使用程式：. 7
六、 實驗流程 . 8
實驗結果 . 9
討論與結論. 22
附錄 . 24
參考資料 . 34

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