LAUSR

Graphical abstract Figure. No Caption available. ABSTRACT The cell adhesion molecule neuroligin2 (NLGN2) regulates GABAergic synapse development, but its role in neural circuit function in the adult hippocampus is unclear. We investigated GABAergic synapses and hippocampus‐dependent behaviors following viral‐vector‐mediated overexpression of NLGN2. Transducing hippocampal neurons with AAV‐NLGN2 increased neuronal expression of NLGN2 and membrane localization of GABAergic postsynaptic proteins gephyrin and GABAAR&ggr;2, and presynaptic vesicular GABA transporter protein (VGAT) suggesting trans‐synaptic enhancement of GABAergic synapses. In contrast, glutamatergic postsynaptic density protein‐95 (PSD‐95) and presynaptic vesicular glutamate transporter (VGLUT) protein were unaltered. Moreover, AAV‐NLGN2 significantly increased parvalbumin immunoreactive (PV+) synaptic boutons co‐localized with postsynaptic gephyrin+ puncta. Furthermore, these changes were demonstrated to lead to cognitive impairments as shown in a battery of hippocampal‐dependent mnemonic tasks and social behaviors.