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。对这种刺激的可靠和准确的反应往往是采取回避行动的关键，在许多情况下可能是生与死的区别。该项目将利用蝗虫和蝗虫的神经系统进行这些研究，因为这些动物对避免碰撞的神经处理特别了解。该项目将使用各种实验技术收集数据，并对负责在不同模拟环境条件下视觉检测接近的物体以避免碰撞的神经路径进行建模。更好地了解导致稳健检测接近物体的生物学机制，可能有助于设计更稳健、更节能的人工避碰系统，如小型无人机或盲人便携式设备。尽管进行了数十年的工作，但导致视觉对象分割或识别的大规模视觉处理仍然知之甚少。在蝗虫中，物体分割以避免碰撞和逃避行为的假设机制依赖于单个神经元扩展的树状结构内的复杂处理，这些神经元在形态和突触组织上类似于小脑中的浦肯野细胞。冲击这个神经元的突触输入被分成具有不同解剖学特性的通路上和通路外，从而可以研究它们是如何结合在一起编码混合了两种对比极性的纹理刺激的。参与OFF输入处理的几个电导普遍存在于各种神经元类型的树突中。因此，了解这些电导是如何实现对象分割的，将有助于理解它们如何在神经系统中实现类似的神经计算。这些树突电导与位于棘波起始区附近的钙和钙激活的钾电导相互作用，从而在紧张性和爆发性之间切换神经元的放电模式。这个项目将阐明这两种放电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所假设的那样。这一结果有望阐明复杂的感官信息如何通过整合不同复杂程度的结果(从单个电导到整个生物体)来促成逃逸行为的产生。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.