Simple, effective, and nontoxic delivery of synthetic oligonucleotides to primary neurons and brain tissue represents a challenge to the use of RNAi as a research tool and therapeutic for neurodegenerative diseases like HD.7 We have shown that hsiRNAs elicit potent silencing in primary neurons in culture, without effect on housekeeping gene expression, and with minimal toxicity at effective doses Additionally, a non-targeting control hsiRNA did not silence any of the mRNAs tested (Htt, Ppib, Hprt), suggesting that these compounds are both sequence specific and on-target. This evidence concerns the gene PPIB and neurodegenerative disease.