β-Catenin in the Adult Visual Cortex Regulates NMDA-Receptor Function and Visual Responses.

The formation, plasticity and maintenance of synaptic connections is regulated by molecular and electrical signals. beta-Catenin is an important protein in these events and regulates cadherin-mediated cell adhesion and the recruitment of pre- and postsynaptic proteins in an activity-dependent fashion. Mutations in the beta-catenin gene can cause cognitive disability and autism, with life-long consequences. Understanding its synaptic function may thus be relevant for the treatment of these disorders. So far, beta-catenin's function has been studied predominantly in cell culture and during development but knowledge on its function in adulthood is limited. Here, we show that ablating beta-catenin in excitatory neurons of the adult visual cortex does not cause the same synaptic deficits previously observed during development. Instead, it reduces NMDA-receptor currents and impairs visual processing. We conclude that beta-catenin remains important for adult cortical function but through different mechanisms than during development.