Hippocampal CA1 Neurons Simultaneously Encode a Variety of Task-Relevant Variables during an Evidence Accumulation Task in Mice

Abstract

The hippocampus encodes spatial information and memory, and it has been implicated in the decision-making process. However, the role of the hippocampus during decision-making and evidence accumulation requires further study. Here, we investigate the population activity of neurons in the mouse hippocampal CA1 during a decision-making, evidence accumulation task. We show that subsets of CA1 neurons significantly encode task-relevant variables, including spatial information, accumulated evidence, upcoming decision, population activation, and others. K-means clustering of neuronal encoding of task-relevant variables in a meta-animal suggests four functional classes of neurons: position, decision-making, signal amplification, and variable-integrating neurons. These four classes support the hypothesis of hippocampal function in constructing relational maps of actions, events, and physical space; classes of neurons encode spatial and decision-making information, which may be related by variable-integrating neurons. These results suggest a broader scope of the hippocampus in processing and relating a variety of variables relevant for the decision-making task and evidence accumulation.