Institute for Perception, Action, and Behaviour, School of Informatics, University of Edinburgh, Edinburgh, Scotland, United Kingdom.
School of Life Sciences, University of Sussex, John Maynard Smith Building, Falmer, Brighton, United Kingdom.
PLoS Comput Biol. 2021 Sep 23;17(9):e1009383. doi: 10.1371/journal.pcbi.1009383. eCollection 2021 Sep.
Insects can navigate efficiently in both novel and familiar environments, and this requires flexiblity in how they are guided by sensory cues. A prominent landmark, for example, can elicit strong innate behaviours (attraction or menotaxis) but can also be used, after learning, as a specific directional cue as part of a navigation memory. However, the mechanisms that allow both pathways to co-exist, interact or override each other are largely unknown. Here we propose a model for the behavioural integration of innate and learned guidance based on the neuroanatomy of the central complex (CX), adapted to control landmark guided behaviours. We consider a reward signal provided either by an innate attraction to landmarks or a long-term visual memory in the mushroom bodies (MB) that modulates the formation of a local vector memory in the CX. Using an operant strategy for a simulated agent exploring a simple world containing a single visual cue, we show how the generated short-term memory can support both innate and learned steering behaviour. In addition, we show how this architecture is consistent with the observed effects of unilateral MB lesions in ants that cause a reversion to innate behaviour. We suggest the formation of a directional memory in the CX can be interpreted as transforming rewarding (positive or negative) sensory signals into a mapping of the environment that describes the geometrical attractiveness (or repulsion). We discuss how this scheme might represent an ideal way to combine multisensory information gathered during the exploration of an environment and support optimal cue integration.
昆虫在新颖和熟悉的环境中都能高效地导航，这需要它们在感知线索的引导下具有灵活性。例如，一个突出的地标可以引发强烈的先天行为（吸引力或趋触性），但在学习后，它也可以作为导航记忆的特定方向线索之一被使用。然而，允许这两种途径共存、相互作用或相互覆盖的机制在很大程度上是未知的。在这里，我们提出了一个基于中央复合体（CX）神经解剖结构的先天和学习引导行为的整合模型，该模型适用于控制地标引导行为。我们考虑了由对地标先天吸引力或蘑菇体（MB）中的长期视觉记忆提供的奖励信号，该信号调节了在 CX 中形成局部向量记忆。使用一种模拟agent 在一个简单世界中探索的操作性策略，我们展示了生成的短期记忆如何支持先天和学习的转向行为。此外，我们还展示了这种架构如何与在蚂蚁中观察到的单侧 MB 损伤的影响一致，这导致了对先天行为的回归。我们认为，CX 中方向记忆的形成可以被解释为将奖励（正或负）感觉信号转化为环境的映射，描述了环境的几何吸引力（或排斥力）。我们讨论了这种方案如何代表一种将在环境探索过程中收集的多感觉信息结合起来并支持最佳线索整合的理想方式。
