ISH was performed on 16-μm sections as described previously.16 (link),17 (link) Sense and antisense riboprobes were generated against full-length CASK IMAGE Clone (catalog number MMM1013-202761641; Dharmacon, Lafayette, CO, USA). Riboprobes were synthesized using digoxigenin (DIG; Roche, Mannheim, Germany) and the MAXI-Script In Vitro Transcription Kit (Ambion, Austin, TX, USA). Probes were hydrolyzed to approximately 500 base pairs. Images were obtained on a Zeiss LSM700 confocal microscope (Carl Zeiss Meditec, Jena, Germany).