We next used gene set enrichment analysis [GSEA]23; a method that assesses the concordance between a defined set of genes and different biological states and is, therefore, extremely useful for the unbiased identification of potential roles of transcripts with unknown function. Leading edge gene analysis, a segment of the GSEA package, was performed on genes that were significantly altered (a total of 4,623 genes) when neurons that had reduced NEAT1 levels, following treatment with NEAT1 ASOs, were activated with KCl and harvested after 3 hours (Supplementary Fig. 7a; Neat1 ASO KCl versus Control ASO KCl). The underlying premise is that sets of genes that are similarly dynamically regulated in a system share a common function. This analysis revealed that NEAT1 expression was significantly associated with expression of multiple ion channel activity gene sets (Fig. 3a). These represent the top regulated gene sets upon neuronal activation following NEAT1 knockdown. We next investigated whether the genes in these enriched gene sets were significantly up or down-regulated in our experimental conditions. First, for the control condition, GSEA performed on 5,339 significantly altered genes
