Neuronal correlates of association learning and memory in the carrion crow

动物的许多习得的适应性行为依赖于刺激之间的任意关联。为了实现这一目标，来自不同感觉器官的行为相关刺激需要跨时间和方式相关联。通过刺激联想来指导行为，既需要短期记忆来连接时间间隔，也需要长期记忆来储存学习到的关系。在非人类灵长类动物中，这种大脑整合功能通常被分配给前额叶皮层的工作。然而，鸟类缺乏六层的新皮层，并显示出非常不同的组织终脑。相反，被称为nidopallium caudolaterale（NCL）的端脑相关脑区与鸟类的高级认知处理有关。这个大脑区域在高度智能的乌鸦鸣禽中尤为突出。该研究项目的目的是了解NCL神经元的神经元活动是否以及如何有助于感觉刺激之间的记忆表征。我们将通过训练腐肉乌鸦（Corvus corone）来学习关联感官刺激来解决这个问题，之后我们将比较乌鸦在练习新颖关联时的表现与他们在熟悉（单模态和跨模态）关联上的表现。同时，将记录corvid NCL中神经元群体的活动。我们将研究神经元记忆信号如何在联想学习过程中出现，它们如何被来自多种感觉方式的输入激活，以及它们如何规避或抑制干扰刺激。这将使我们能够比较预期的差异和共同点的神经元基础的关联记忆在乌鸦的非人类灵长类动物的研究结果。这些见解将促进我们理解鸟类大脑如何基于趋同进化产生关联的短期和长期记忆，以及智能脊椎动物大脑的设计存在哪些进化限制。

Many of the learned, adaptive behaviors of animals depend on arbitrary associations between stimuli. To that aim, behaviorally relevant stimuli from different sense organs need to be related across time and modalities. The guiding of behavior by stimulus associations requires both short-term memory to bridge time intervals, as well as long-term memory storage of learnt relationships. In nonhuman primates, such integrative brain functions are typically assigned to the workings of the prefrontal cortex. Birds, however, lack a six-layered neocortex and show a very differently organized endbrain. Instead, the associative telencephalic brain area termed nidopallium caudolaterale (NCL) has been related to high-level cognitive processing in birds. This brain area is particularly prominent in highly intelligent corvid songbirds. The purpose of the proposed research project is to understand if and how neuronal activity of NCL neurons contributes to memory representations between sensory stimuli. We will approach this issue by training carrion crows (Corvus corone) to learn to associate sensory stimuli and later we will compare the crows performance while practicing novel associations with their performance on familiar (uni-modal and cross-modal) associations. At the same time, the activity of populations of neurons in the corvid NCL will be recorded. We will study how neuronal memory signals emerge during associative learning, how they can be activated by input from multiple sensory modalities, and how they may circumvent or suppress distractor stimuli. This will allow us to compare expected differences and commonalities of the neuronal basis of association memory in crows to findings in nonhuman primates. Such insights will foster our understanding of how bird brains give rise to associative short- and long-term memories based on convergent evolution, and which evolutionary constraints exist for the design of intelligent vertebrate brains.