Optical Recording and Analysis of Neural Activities in Odor response of Larva Silkworm Moth

研究大量神经活动的一种方法是使用荧光电压敏感染料来同时跟踪许多神经元的神经活动。电压敏感染料首先应用于嗅球的神经元。然后用紫外线照射嗅球，并通过显微镜拍摄暴露嗅球的视频图像。当紫外光所在的细胞去极化时，紫外光刺激电压敏感染料发光。通过使用计算机从气味存在时获得的图像中减去背景图像。我们在蚕蛾的大脑中进行了体内光学记录，以研究神经元群体对传递给动物的气味的反应。成年雄蚕蛾在羽化后2 ~ 4天内使用。4℃降温麻醉约30min后，在脑上方打开头囊，去除头部大部分肌肉。用细镊子去除脑鞘，用电压敏感染料RH414（分子探针）染色。将RH414染料以3mg /ml的浓度溶解于生理盐水中。多余的染料用生理盐水洗掉了。这些信号叠加在人工智能的亮场图像上，直接将响应与人工智能的结构联系起来。气味在AL中引起特定的时空兴奋模式。活跃肾小球的特定集合可能以组合方式代表气味。气味混合引起的模式是单一气味反应的组合。气味不仅表现为空间活动模式，而且表现为随时间演变的模式。

One approach to the study of massed neural activity has been to use fluorescent voltage-sensitive dyes to track the neural activity of many neurons at once. The voltage-sensitive dye is first applied to the neurons of the olfactory bulb. The bulb is then illuminated with ultraviolet light, and video images of the exposed olfactory bulb are taken through a microscope. The UV light stimulates the voltage-sensitive dye to give off light when the cell in which it is located depolarizes. By using a computer to subtract the background image from the image obtained when the odor is present. We made optical recordings in vivo in the silkworm moth brain to investigate neuronal population responses to odorants delivered to the animal. Adult male silkworm moths were used within 2-4 days after eclosion. After anesthesia by cooling at 4℃ for about 30 min, the head capsule was opened above the brain, and most of the muscles in the head were removed. The brain was desheathed by fine tweezers and stained with a voltage-sensitive dye RH414 (Molecular probe). The RH414 dye was dissolved in a physiological saline at a concentration of 3 mg/ml. Excess dye was washed off with the saline. The signals were superimposed on the bright-field image of AL to correlate the responses directly with the AL structure. Odors evoked specific spatio-temporal excitation patterns in the AL. Specific ensembles of active glomeruli are likely to represent odors in a combinatorial manner. Odor blends evoked patterns that were combinations of the single odorant responses. Odors are not only represented as spatial activity patterns, but as patterns that evolve over time.