Neuronal computation underlying the generation of a transitive inference in mice

推理需要在从未直接经历过的项目或事件之间形成灵活的关系的能力。人类和动物可以借鉴以前的经验，将来自多个离散的、松散相关的项目或事件的信息组合到一张“认知地图”中。这个世界的内部模型将问题的结构概括为一个共同的空间或抽象关系知识框架。我们的目标是理解信息泛化背后的机制，使适应行为能够跨越相关的刺激。我们设计了一项传递性推理任务，有两组平行的气味三联体，同时使用高密度硅探针记录该任务中涉及的多个海马区和皮层亚区的尖峰活动和局部场电位(LFP)。我们问，海马体(HPC)是否传达一种合取代码，将外侧内嗅皮层(LEC)编码的当前特定感觉刺激连续映射到内侧内嗅皮层(MEC)编码的任务的一般抽象结构上。首先，我们的目标是识别在呈现每种特定气味时选择性激活的神经元。我们将研究代表不同气味的神经元的放电模式之间的时间关系，以确定气味呈现的顺序性是否在神经表征中保持不变。我们还将评估参与任务的大脑区域之间的时间关系，以确定推理形成和提取过程中信息流的方向性。最后，我们将关注活跃和不活跃行为状态中不同频率的大脑振荡，以确定它们在同步个体气味表征之间和大脑区域之间的活动方面的重要性，潜在地嵌套认知捷径，从而产生灵活的推理。

Inferential reasoning entails the ability to form flexible relationships between items or events that were never directly experienced together. Humans and animals can draw on previous experience and combine information from multiple discrete, loosely related items or events into a 'cognitive map'. This internal model of the world generalises the structure of problems onto a common framework of spatial or abstract relational knowledge. We aim to understand the mechanism underlying the generalisation of information enabling adaptive behaviour across related stimuli. We designed a transitive inference task with two parallel groups of odour triplets, while simultaneously recording spiking activity and local field potential (LFP) in multiple hippocampal and cortical subregions implicated in this task using high-density silicon probes. We ask whether the hippocampus (HPC) conveys a conjunctive code, continuously mapping the current specific sensory stimuli coded by lateral entorhinal cortex (LEC) onto the general abstract structure of the task coded by medial entorhinal cortex (MEC). First, we aim to identify neurons selectively active upon presentation of each specific odour. We will examine the temporal relationship between firing patterns of neurons representing different odours to determine whether the sequentiality of odour presentation is maintained in the neural representation. We will also assess the temporal relationship across brain areas participating in the task to determine the directionality of information flow during both the formation and retrieval of the inference. Finally, we will focus on brain oscillations at different frequencies during active and inactive behavioural states to determine their importance in synchronizing activity between representations for individual odours and between brain areas, potentially nesting cognitive short-cuts giving rise to flexible inferences.