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关系的能力。人类和动物可以利用以往的经验，将多个离散的、松散相关的项目或事件的信息组合成一张“认知地图”。这个世界的内部模型将问题的结构推广到空间或抽象关系知识的共同框架上。我们的目的是了解信息泛化的机制，使相关刺激的适应性行为。我们设计了一个具有两组气味三联体的传递推理任务，同时使用高密度硅探针记录了与该任务相关的多个海马和皮层亚区的峰值活动和局部场电位（LFP）。我们研究海马体（HPC）是否传递了一种连接编码，将当前由外侧内嗅皮层（LEC）编码的特定感觉刺激持续映射到由内侧内嗅皮层（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每种特定气味呈现时选择性活跃的神经元。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是否在神经表征中保持。我们还将评估参与任务的大脑区域的时间关系，以确定推理形成和检索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下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中的重要性，潜在的筑巢认知捷径会产生灵活的推理。

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.