Crafton, Brittany Nicole

While the thalamus and hippocampus are generally understood to contribute to mammalian spatial navigation, the degree to which thalamic input contributes to representations of space during navigation remains unclear. Specifically, anterior dorsal thalamic nuclei (ADN) provide a relational or directional framework known as the head direction (HD) network, which is hypothesized to play a significant role in guiding hippocampal-dependent navigation. The current study focuses on the contribution of the ADN to direction and place-dependent spatial navigation in adult male C57BL6J mice. An inhibitory chemogenetic (hM4Di) receptor was bilaterally expressed in the ADN after viral stereotaxic injection. Mice were trained in a spatially focused task, the Morris water maze (MWM), and after systemic administration of the hM4Di agonist, clozapine-Noxide (CNO) at 5mg/kg, demonstrated equivalent preference for using directional or place-based search behavior. These results suggest that the selective silencing of ADN at 5mg/kg CNO does not negatively affect spatial navigation in mice.