Identification of conserved circuit logic in temperature navigation behavior in fish and fly

鱼和苍蝇温度导航行为中保守电路逻辑的识别

• 批准号: 430156228
• 负责人: Professorin Dr. Ilona Grunwald Kadow
• 金额: --
• 依托单位: Institut für Physiologie II
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/430156228?language=en
• 关键词: Identification; conserved; circuit; logic; temperature

Temperature affects the physiological processes of all organisms. A failure to assess its value, valence, and rate of change can have a variety of consequences from tissue damage to failure of the entire system. Thus, most organisms have evolved strategies to maintain their body temperature within a specific narrow range. Regardless of the specific strategy adopted, the nervous system plays an important role in detecting temperature changes, evaluating them in the current context and state of the animal, and directing both physiological and behavioral changes. The evolutionary relationship between the function of the nervous system in temperature regulation between different species remains unclear. Through the work of a PhD student funded by the previous funding period of this SPP, we have significantly advanced our understanding of the role of the nervous system in temperature homeostasis in ectotherms as compared to endotherms. Through novel behavioral assays, we have found that fish and flies use highly similar strategies to navigate temperature gradients to remain in or return to a preferred temperature range (‘homeostatic navigation’). We further showed that fish achieve thermoregulation through a neural network connecting the preoptic area of the hypothalamus (PoA) to brain areas enabling spatial navigation. PoA drives reorientation when thermal conditions are worsening and conveys this information for instructing future motor actions to the navigation-controlling habenula (Hb) - interpeduncular nucleus (IPN) circuit. These results suggest a conserved function of the PoA in thermoregulation acting through species- specific neural networks. Furthermore, we propose that homeostatic navigation arose from an ancient chemotaxis navigation circuit that was subsequently extended to serve in other sensory modalities. In the next funding period, we want to (i) identify the functional equivalents of the PoA and the Hb in the fly by combining state-of-the-art in vivo imaging and optogenetic manipulation during homeostatic navigation, (ii) characterize the role of serotonergic signaling in homeostatic navigation in fish and fly (feedback and feedforward modulation), and (iii) address the role of homeostatic setpoints in triggering temperature navigation by changing the temperature setpoint of fish and flies though developmental temperature, exogenous pyrogens, and hunger states. Finally, we will use these new data to update and refine the general and species-specific contribution of neuron types and circuit motives in a computational circuit model. Together the expected results will show how joint homeostatic needs are processed by functionally equivalent brain regions or neurons and which role the homeostatic setpoint plays in triggering behavior to improve survival chances of evolutionary distinct species.

温度影响所有生物体的生理过程。未能评估其价值、化合价和变化率可能会产生从组织损伤到整个系统故障的各种后果。因此，大多数生物体已经进化出将体温维持在特定狭窄范围内的策略。无论采用何种具体策略，神经系统在检测温度变化、在动物当前环境和状态下评估温度变化以及指导生理和行为变化方面都发挥着重要作用。不同物种之间神经系统温度调节功能之间的进化关系仍不清楚。通过本 SPP 上一个资助期资助的一名博士生的工作，我们显着加深了对变温动物与恒温动物相比神经系统在温度稳态中的作用的理解。通过新颖的行为测定，我们发现鱼和苍蝇使用高度相似的策略来导航温度梯度以保持或返回到首选的温度范围（“稳态导航”）。我们进一步表明，鱼类通过连接下丘脑视前区（PoA）和能够进行空间导航的大脑区域的神经网络来实现体温调节。当热条件恶化时，PoA 会驱动重新定向，并将此信息传递给导航控制缰核 (Hb) - 脚间核 (IPN) 回路，以指示未来的运动动作。这些结果表明 PoA 在通过物种特异性神经网络发挥温度调节作用时具有保守功能。此外，我们提出稳态导航源于古老的趋化性导航电路，随后扩展到其他感觉方式。在下一个资助期间，我们希望（i）通过在稳态导航过程中结合最先进的体内成像和光遗传学操作来确定果蝇中 PoA 和 Hb 的功能等价物，（ii）表征鱼和果蝇稳态导航中血清素信号的作用（反馈和前馈调制），以及（iii）解决稳态设定点在触发温度导航中的作用 通过发育温度、外源热原和饥饿状态改变鱼和苍蝇的温度设定点。最后，我们将使用这些新数据来更新和完善计算电路模型中神经元类型和电路动机的一般和特定物种的贡献。预期结果将共同显示功能等效的大脑区域或神经元如何处理关节稳态需求，以及稳态设定点在触发行为以提高进化不同物种的生存机会中发挥的作用。