Notch signaling is essential for the maintenance of adult neural stem cells in vivo. Andreu-Agulló and colleagues show that PEDF, released from endothelial cells, enhances Notch signaling in the mouse subependymal zone by inactivating a repressor of Notch target genes. On the cover are daughter cell pairs stained for epidermal growth factor receptor (red), the intracellular domain of Notch (green) and DAPI (blue).15141481

GPR17 is an orphan G protein-coupled receptor that is thought to interact with transcription factor Olig1, which promotes oligodendrocyte maturation and is required for myelin repair. Chen and colleagues show that GPR17 opposes the action of Olig1 in oligodendrocytes and acts as a negative regulator of oligodendrocyte maturation and myelination. The cover shows cultured oligodendrocytes differentiated from hippocampal progenitors.p 1398

The amygdala is critical for processing information about emotion, but little is known about what role it might have in human behavioral interactions. Kennedy and colleagues report that a patient with complete bilateral amygdala lesions lacks any sense of personal space and that, in healthy controls, the amygdala is activated by close personal proximity.121712241226

Selective targeting of specific neuronal populations is crucial for much of neuroscience. Roska and colleagues screened 536 BAC transgenic mouse lines from the GENSAT collection for specific reporter expression in the retina. On the cover is a mouse retinal section with neuronal nuclei stained blue and starburst amacrine cells stained red. The green is the line-specific expression of GFP.(p 1197)

Shu and colleagues show that two sodium channel subtypes, a high-threshold Nav1.2 and a low-threshold Nav1.6, are asymmetrically distributed in the axon initial segment (AIS). This asymmetrical distribution explains many of the unique properties of the AIS, including its generation of backpropagating action potentials. Cover design by Jiafeng Zhao.959996

People use auditory feedback to maintain stable vocal performance. In this issue, Sober and Brainard find that adult Bengalese finches also use auditory feedback to correct vocal errors in adulthood. This suggests that lifelong error correction may be a general principle of learned vocal behavior.p 927

Hearing loss has profound effects for both early development and the elderly. A better understanding of the process by which sounds are translated into neural signals and used to support cognitive function is interesting in its own right, but this research has also informed efforts to ameliorate hearing loss. In this issue, we present a collection of Perspectives and Reviews on clinical and research advances in the neurobiology of hearing.(pp 677–724)

Experiments often generate large amounts of data, of which only a small fraction is typically presented in a publication. This inevitable data selection critically affects the conclusions. In neuroimaging experiments, for example, voxels (cubes in picture) are selected in a region of interest (reddish squares). The random noise in the data (dice) co-determines selection. Circularity (MÖbius band) can arise in unexpected ways when our focus on a region of interest leads us to neglect the background of excluded data (gray band). Although the problem is well understood in theory, some widespread practices may need to be adjusted.p 535

Correlated network activity is important in the development of many neural circuits. Watt et al. characterize monsynaptic connections between Purkinje cells of the juvenile cerebellum and use these measurements to model the generation of traveling waves of activity between connected Purkinje cells. They validate their model with observations in juvenile cerebellar cortex.p 463

Bright light vision requires rapid regeneration of the photosensitive chromophore in cone photoreceptors. In this issue, Wang and colleagues demonstrate that such rapid regeneration in salamanders is accomplished via a pathway that resides in retinal Muller glia, with the final step being performed in the cones themselves.p 295

Categorical perception is critical for processing vocal communication. In this issue, Prather and colleagues show that individual swamp sparrow sensorimotor neurons exhibit categorical responses to the features of their songs. They also find that the neuronal response boundary predicts the categorical perceptual boundary for the bird’s own song dialect. The cover is a photograph of a swamp sparrow courtesy of Rob Lachlan.p 221

Retinitis pigmentosa is characterized by an initial loss of rod photoreceptors followed by a progressive loss of cones, although the known mutations causing retinitis pigmentosa are all in rod-specific genes. Punzo et al. now report that rod-specific mutations in the insulin/mTOR pathway may contribute to cone death as a result of photoreceptor starvation. The cover depicts phosphorylated mTOR in dorsal cone receptors (cell bodies in magenta, outer segments in green and mTOR in red).

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