a-b, Quantitation of intron accumulation at the selected region of Gabra2, Gng7, Kcnh1, and Camk1d. IGV software was used to display RNA read density with same scale range in each gene from RNA-seq (ex: exon; in: intron). Red boxes show selected regions for quantification. Intron reads % was analyzed by RNA-seq ((intron-exon junctions + introns)/(intron-exon junctions + introns + exons + exon-exon junctions)). Intron retention % was analyzed by RT-PCR ((intron-containing PCR band intensity)/(intron-containing PCR band intensity + exon-exon PCR band intensity)). Gabra2: intron 6 vs exon 6 and 7; Gng7: intron 2 vs exon 2 and 3, Kcnh1: intron 9 vs exon 9 and 10, and Camk1d: intron 5 vs exon 5 and 6. 12-month-old: WT n = 3, Tg n = 3. Scale bar, 10 kb. Data are shown as mean ± SEM. Statistical significance was analyzed by Student's t-test. Data are shown as mean ± SEM, * p < 0.05; ** p < 0.01; *** p < 0.001.