Total RNA was isolated from the central nervous system (CNS) tissues of 3-, 6-, and 18-month-old Lymnaea stagnalis using RNAeasy Mini Kit (Qiagen). There are four replicate samples for each age group and for each sample the CNS of 10 animals were pooled. After RNA extraction, genomic DNA (gDNA) was removed via the TURBO DNA-free kit (Invitrogen). RNA-sequencing was performed by Novogene Corporation Inc using Illumina NovaSeq 6000 platform (Paired-end, 150 bp, insert size 250-300 bp). The goal is to investigate transcriptomic profile of CNS in young, adult, and old animals.