Mouse perfusion, preparation of frozen brain sections, and immunofluorescence staining of sections were previously described [31 (link)]. Antibodies used were rabbit anti-MAP2 for detection of dendrites (EMD Millipore, Burlington, MA, 1:150) and mouse anti-NeuN for detection of neuronal nuclei (EMD Millipore, 1:150) followed by goat-anti-rabbit IgG Alexa 488 and donkey-anti-mouse IgG Alexa 594 (ThermoFisher Scientific, Waltham, MA, 1:150), respectively. Images were captured and fluorescence signals quantified as described [31 (link)].