Only about 2% of our genome is actively translated into proteins, however, up to 80% of the entire genome is transcribed into RNA. Despite good evidence for a good portion of our DNA being indeed “junk-DNA”, more recent evidence suggest that the non-coding part of our genome has relevant function in genome stability, regulation and function. Among the broad variety of non-coding RNAs expressed from the mammalian genome, we focus on circular RNAs, which form a unique closed-loop structure. Circular RNAs are expressed from many neuron-specific loci and show an enrichment in the brain. However, their function is largely unknown. We investigate circular RNAs in post-mortem brain tissue and in animal models to better understand their role in the healthy brain as well as in disease.