Young adult-born granule cells and CA1 population coding during spatial pattern separation

The hippocampal formation transforms experiences into distributed neural representations that support the discrimination of similar events. Within this circuit, adult-born granule cells (ABGCs) in the dentate gyrus (DG) have been proposed to contribute to pattern separation, yet their influence on downstream population coding remains largely unresolved. To address this question, a spontaneous object location recognition task (SOLR) was combined with high-throughput calcium imaging in CA1. Neuronal activity was recorded while mice experienced different spatial object configurations in the SOLR, varying in their demands for pattern separation. CA1 population activity was then characterized across these different spatial configurations. In addition, CA1 activity was examined following reversible silencing of young ABGCs to assess whether their contribution is reflected in downstream spatial representations. By combining population calcium imaging across SOLR conditions with selective manipulation of young ABGCs, this approach provides a means to investigate how adult-born neurons in the DG may influence the organization of spatial representations in CA1 during pattern separation.