Convergence of direction, location and theta in the rat anteroventral thalamic nucleus

Retrosplenial cortex (RSC) is a cortical region that computes heading direction from landmark information, but how it does this remains unknown. Recently we found that its two major subregions receive differential projections from two anteroventral thalamic (AV) subfields; dorsomedial (AVDM) and ventrolateral (AVVL). To probe the respective contributions of these inputs we recorded single neurons and local field potentials from AV in rats during foraging. We observed and characterized neurons modulated by theta oscillations, heading direction, and a conjunction of these. Unexpectedly, we also discovered place cells (neurons modulated by location). Consistent with the notion that AV contains two parallel subcircuits, there was a prevalence of non-conjunctive cells in AVDM, and of conjunctive and place neurons in AVVL. This integration of spatial and movement signals in AV is consistent with a thalamic role in multimodal integration and may be important for supplying the spatial information that modulates RSC directional responding.