Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA.
Cell. 2012 Feb 3;148(3):583-95. doi: 10.1016/j.cell.2011.12.022.
Behavior cannot be predicted from a "connectome" because the brain contains a chemical "map" of neuromodulation superimposed upon its synaptic connectivity map. Neuromodulation changes how neural circuits process information in different states, such as hunger or arousal. Here we describe a genetically based method to map, in an unbiased and brain-wide manner, sites of neuromodulation under different conditions in the Drosophila brain. This method, and genetic perturbations, reveal that the well-known effect of hunger to enhance behavioral sensitivity to sugar is mediated, at least in part, by the release of dopamine onto primary gustatory sensory neurons, which enhances sugar-evoked calcium influx. These data reinforce the concept that sensory neurons constitute an important locus for state-dependent gain control of behavior and introduce a methodology that can be extended to other neuromodulators and model organisms.
由于大脑中存在化学调制“图谱”，叠加在其突触连接“图谱”之上，因此行为不能仅从“连接组”来预测。调制会改变神经回路在不同状态（如饥饿或觉醒）下处理信息的方式。在这里，我们描述了一种基于遗传的方法，以在果蝇大脑中以无偏和全脑的方式来绘制不同条件下调制位点的图谱。该方法和遗传扰动揭示了饥饿增强对糖敏感性的这种众所周知的效应至少部分是通过多巴胺释放到主要味觉感觉神经元来介导的，这增强了糖诱导的钙内流。这些数据强化了感觉神经元构成行为状态相关增益控制的重要位置的概念，并引入了一种可以扩展到其他神经调制物和模式生物的方法。
