Cerebellar contributions to tau-mediated cognitive and behavioral dysfunction.

Dementia is characterized by loss of cognitive function, social deficits, and emotional impairment and is prevalent in tau-mediated disorders. However, the mechanisms underlying this cognitive and behavioral dysfunction remain uncertain, as phenotypes do not necessarily correlate well with the presence of tau pathology. Here, we identify critical roles for the cerebellum in regulating cognition and behavior in a tauopathy mouse model. We find that social and fear memory deficits emerge much later than tau pathology and that cerebellar Purkinje cell (PC) dysfunction coincides with the onset of memory phenotypes in P301S tau mutant mice. Similarly, a chemogenetic reduction of PC excitability in control mice results in social memory deficits. We further demonstrate that a chemogenetic increase in PC excitability improves cognitive and behavioral dysfunction in P301S mutants. Together, these findings support critical roles for the cerebellum in regulating tauopathy-relevant cognitive and behavioral deficits while also informing potential therapeutic avenues for these conditions.