The recent assembly of the adult Drosophila melanogaster central brain connectome, containing more than 125,000 neurons and 50 million synaptic connections, provides a template for examining sensory processing throughout the brain^1,2. Here we create a leaky integrate-and-fire computational model of the entire Drosophila brain, on the basis of neural connectivity and neurotransmitter identity³, to study circuit properties of feeding and grooming behaviours. We show that activation of sugar-sensing or water-sensing gustatory neurons in the computational model accurately predicts neurons that respond to tastes and are required for feeding initiation⁴. In addition, using the model to activate neurons in the feeding region of the Drosophila brain predicts those that elicit motor neuron firing⁵—a testable hypothesis that we validate by optogenetic activation and behavioural studies. Activating different classes of gustatory neurons in the model makes accurate predictions of how several taste modalities interact, providing circuit-level insight into aversive and appetitive taste processing. Additionally, we applied this model to mechanosensory circuits and found that computational activation of mechanosensory neurons predicts activation of a small set of neurons comprising the antennal grooming circuit, and accurately describes the circuit response upon activation of different mechanosensory subtypes^6,7,8,9,10. Our results demonstrate that modelling brain circuits using only synapse-level connectivity and predicted neurotransmitter identity generates experimentally testable hypotheses and can describe complete sensorimotor transformations.

最近组装的成年黑腹果蝇中枢脑连接组包含超过 125,000 个神经元和 5000 万个突触连接，为检查整个大脑的感觉处理提供了模板^1,2。在这里，我们根据神经连接和神经递质身份³ 创建了一个整个果蝇大脑的泄漏集成和发射计算模型，以研究进食和梳理行为的电路特性。我们表明，计算模型中糖感应或水感应味觉神经元的激活准确预测了对味道做出反应并且是进食启动所需的神经元⁴。此外，使用该模型激活果蝇大脑摄食区域的神经元可以预测那些引发运动神经元放电的神经元⁵——我们通过光遗传学激活和行为研究验证了这一可检验的假设。在模型中激活不同类别的味觉神经元可以准确预测几种味觉模式如何相互作用，从而提供对厌恶和食欲味觉加工的回路级见解。此外，我们将该模型应用于机械感觉回路，发现机械感应神经元的计算激活预测了构成触角梳理回路的一小群神经元的激活，并准确描述了不同机械感应亚型^{6、7、8、9、10} 激活时的回路反应。我们的结果表明，仅使用突触水平连接和预测的神经递质身份对大脑回路进行建模会产生实验可检验的假设，并且可以描述完整的感觉运动转换。