MicroRNAs are important regulatory factors in brain development and function. DNA variations disrupting their function may contribute to neurodevelopmental disorders such as autism. Operating at the posttranscriptional level, microRNAs regulate broad yet controlled sets of target genes typically via interacting with target sites found in 3' untranslated regions of mRNA transcripts. Efforts to identify microRNAs contributing to autism risk have involved examining differences in their expression patterns, mutations that affect their function, and their interaction with autism-risk genes. However, there have yet to be any robustly replicated candidate microRNAs supported by these functional evidences. Knowing what genes a microRNA targets is a major challenge in the field, and represents an important first step in investigating their biological role and contribution to autism. A huge thank-you for my work-mates-for their company, advice, humour and encouragement that have made for friendly and welcoming offices and labs. More professionally, special thanks to Joon, Flavia, Michelle, Nivetha, Jing and Ramesh for the many insightful discussions, shared links and resources, technical advice, tips, training, help and draft-reading that have pushed this work forward. Lastly, thanks to my friends and family for many long years of support and encouragement. Especially Brent for helping me 'science' through his patient understanding, proofreading, sympathetic ear, welltimed provision of coffee and unwavering support.