Elucidating the Role of ON and OFF Visual Pathways in Object Segmentation for Escape Behavior

该项目将研究神经系统如何对与碰撞过程中接近的物体相关的视觉刺激产生特定反应。对这种刺激作出可靠和精确的反应，往往是采取规避行动的关键，在许多情况下，可能是生与死的差别。该项目将使用蚱蜢和蝗虫的神经系统进行这些调查，因为这些动物的避碰神经处理机制已经被很好地理解了。该项目将使用各种实验技术收集数据，并对神经通路进行建模，这些神经通路负责在不同模拟环境条件下对接近的物体进行视觉检测，从而避免碰撞。更好地了解导致对接近物体进行稳健检测的生物机制，可能有助于设计更稳健和节能的人工避碰系统，如小型无人机或盲人便携式设备。尽管几十年的工作，大规模的视觉处理，导致视觉对象分割或识别仍然知之甚少。在蚱蜢中，物体分割避免碰撞和逃避行为的假设机制依赖于单个神经元的扩展树突树内的复杂处理，其形态和突触组织与小脑中的浦肯野细胞相似。撞击该神经元的突触输入被分离成具有不同解剖特性的on和OFF通路，从而可以研究它们如何结合起来编码混合两种相反极性的纹理刺激。在各种类型的神经元树突中，参与OFF输入处理的几种电导是普遍存在的。因此，理解这些电导如何实现目标分割将揭示它们如何在神经系统中实现类似的神经计算。这些树突电导与Ca+2和Ca+2激活的K+电导相互作用，这些电导位于尖峰起始区附近，可以在紧张和爆发之间切换神经元的放电模式。这个项目将阐明这两种发射模式之间的转换如何有助于神经计算，就像在其他感觉系统中假设的那样。这些结果有望通过整合从单个电导到整个生物体的不同复杂性水平的结果，揭示复杂的感觉信息如何有助于产生逃跑行为。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The project will investigate how the nervous system generates specific responses to visual stimuli associated with objects approaching on a collision course. Reliable and precise responses to such stimuli is often critical to take evasive actions and may be the difference between life and death in many situations. The project will use the nervous system of grasshoppers and locusts for these investigations as the neural processing underlying collision avoidance is particularly well understood in these animals. The project will gather data using a variety of experimental techniques and model the neural pathways responsible for the visual detection of approaching objects leading to collision avoidance under different simulated environmental conditions. A better understanding of the biological mechanisms leading to the robust detection of approaching objects may help design more robust and energy-efficient artificial collision avoidance systems such as small drones or portable devices for blind people.Despite decades of work, the large-scale visual processing that results in visual object segmentation or identification remains poorly understood. In grasshoppers, the postulated mechanisms of object segmentation for collision avoidance and escape behavior rely on complex processing within the extended dendritic tree of a single neuron resembling in its morphology and synaptic organization that of a Purkinje cell in the cerebellum. Synaptic inputs impinging on this neuron are segregated into ON and OFF pathways with distinct anatomical properties allowing to investigate how they combine to encode textured stimuli mixing both contrast polarities. Several conductances involved in the processing of OFF inputs are ubiquitous in the dendrites of a wide range of neuron types. Thus, understanding how these conductances implement object segmentation will shed light on how they could implement similar neural computations across the nervous system. These dendritic conductances interact with Ca+2 and Ca+2-activated K+ conductances located close to the spike initiation zone that switch the neuron's firing mode between tonic and bursting. This project will shed light on how transitions between these two firing modes contribute to neural computation, as has been postulated in other sensory systems. The results are expected to shed light on how complex sensory information contributes to the generation of escape behaviors by integrating results at different levels of complexity, ranging from single conductances to whole organisms.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.