●It's about (molecular) time. Allada, R. Nature Cell Biology December (2004)

A review of the book Molecular Biology of Circadian Rhythms edited by A. Sehgal.

●At the root of brain cancer. Clarke, M. F. Nature 18 November (2004)

The identification in humans of a small subpopulation of cells, known as 'brain cancer stem cells', is discussed in this News and Views article. These cells are thought to drive tumour formation, and could be a potential therapeutic target.

●Multiple routes to similar network output. Hooper, S. L. Nature Neuroscience December (2004)

Computational modelling indicates that similar network outputs can be generated from many combinations of synaptic strengths and intrinsic neuronal properties by balancing these parameter sets rather than fine-tuning them individually, according to this News and Views article.

●True neuroscience. Dudai, Y. Nature Neuroscience December (2004)

A review of the book The Physiology of Truth: Neuroscience and Human Knowledge by J.-P. Changeux.

●When the going gets tough, the cingulate gets going. Gehring, W. J. & Taylor, S. F. Nature Neuroscience December (2004)

A News and Views article that discusses work on the role of the anterior cingulate cortex in forming behavioural strategies. The researchers used recordings of single neurons and surgical ablation.

●The neuropathogenesis of AIDS. González-Scarano, F. & Martín-García, J. Nature Reviews Immunology January (2005)

●X-linked mental retardation. Ropers, H.-H. & Hamel, B. C. J. Nature Reviews Genetics January (2005)

●Back to the future: carbon dioxide chemoreceptors in the mammalian brain. Mitchell, G. S. Nature Neuroscience December (2004)

A News and Views piece on the discovery of CO 2 -sensitive neurons close to the ventral medullary surface, and the implications that this might have for theories of mammalian respiratory control.

●A molecular light switch turns off neural activity. ●Allen, C. Nature Neuroscience December (2004)

A new technique to selectively manipulate activity in specific sets of neurons using a potassium channel blocker attached to a photoisomerizable tether, which can be precisely and reversibly activated by light, is described in this News and Views article.