Hippocampi were dissected, snap-frozen on dry ice and stored at -80C. Total RNA was prepared using the RNeasy PowerLyzer Tissue & Cell kit (Qiagen). RNA quality was assessed by estimating the A260/A280 and A260/A230 ratios bynanodrop. RNA integrity was determined by running Agilent Bioanalyzer 2100 gel 1 µg of total RNA per sample was enriched for polyA RNA and converted into libraries using the Kapa mRNA Hyper Prep Kit for Illumina Platforms (KAPA Biosystems)