This issue of Nature Reviews Neuroscience covers topics ranging from music to circadian rhythms, photoreceptor development, the axon initial segment and glycogen synthase kinase 3 (GSK3) signalling in development.

On page 599, Kraus and Chandrasekaran describe how music training promotes plasticity in the cortex and the brainstem. They show that this enhances auditory processing of music and of speech and language, and argue that music training should therefore be an integral part of school curricula.

The importance of circadian rhythmicity for various brain functions is the focus of two articles in this issue. In a Review on page 577, Gerstner and Yin review data showing that molecular pathways that are involved in circadian rhythmicity affect synaptic plasticity and memory formation. Circadian rhythmicity and sleep are often disturbed in patients with psychiatric or neurodegenerative disorders. On page 589, Wulff et al. discuss the mechanisms that might underlie this link and argue that restoring normal sleep rhythms could reduce some of the symptoms of these disorders.

GSK3 signalling has a key role in neurodevelopment. On page 539, Hur and Zhou review the mechanisms that regulate GSK3 activity and discuss how this molecule controls neurogenesis, neuronal polarization and axon growth. Neuronal polarity is also the topic of the Review by Rasband on page 552. He discusses the role of the axon initial segment (AIS) in the development and maintenance of anatomical, functional and subcellular polarity, and the consequences of AIS disruption for neuronal function.

Finally, on page 563, Swaroop and colleagues discuss a model of photoreceptor development in which transcriptional signals at two key points in development determine whether a common photoreceptor precursor acquires a rod or a specific cone identity.