Distinct contributions of hippocampal and prefrontal afferents to nucleus reuniens during spatial working memory

Abstract

Spatial working memory, the ability to acquire, maintain, and apply spatially relevant information over a short temporal gap, has been demonstrated to depend on functional interactions between the hippocampus and medial prefrontal cortex. Recently, the midline thalamic nuclei, nucleus reuniens, has gained attention for its potential role in coordinating circuit activity that supports spatial working memory. However, the functional involvement of nucleus reuniens afferents during distinct processes of spatial working memory have yet to be established. Using an optogenetic projection suppression approach, we find that dorsal subiculum-nucleus reuniens afferents are critical for the encoding of task-relevant spatial cues, while medial prefrontal-nucleus reuniens afferents support the maintenance of these spatial representations. These findings indicate pathway specific roles for nucleus reuniens afferents during the encoding, and maintenance of spatial information necessary for successful spatial working memory.