Reviews & Analysis

The mechanisms of sleep have been studied in Drosophila melanogaster, which show behaviors reminiscent of sleep in vertebrates. A new study identifies a growth factor signaling pathway involved in sleep regulation and consolidation in this model. Inhibiting this pathway causes a sleep pattern that is similar to insomnia in humans.

Lasting synaptic plasticity requires precise local regulation of protein expression. A recent paper reports that the postsynaptic activity–induced arc mRNA is a target for rapid degradation by the 'nonsense-mediated decay' pathway.

Memories for motor skills become resistant to interference during wakefulness within a few hours. A new study shows that such stabilization occurs faster during sleep, possibly by activating a different type of consolidation.

Central pattern generators provide the basic stepping pattern in walking, but cannot adjust for the environment. A new study of human locomotion shows a pattern of changes in independent neural controllers for left and right legs.

Pheromones influence sexual behavior and reproduction in rodents. A new report suggests that neurogenesis induced in the female mouse brain by male pheromones governs the choice of dominant males as mates.

Brain-derived neurotrophic factor (BDNF) is important in regulating synaptic plasticity in the brain areas that process reward information. A new study reports that BDNF in the nucleus accumbens, a brain area critical for the rewarding effects of cocaine, promotes persistent cocaine-seeking behaviors and heightens relapse vulnerability.

A high-resolution crystal structure of the ligand-binding domain of the human nicotinic acetylcholine receptor α subunit, with three point mutations to improve its crystallization, provides both reassurance and exciting new insights.

Representations of pitch and space seem to interact. A new study now reports that people with amusia, a pitch processing deficit, do not show the interference between these concepts that is found in control subjects.

A recent paper suggests a new form of inhibitory circuit in cortex, in which a pyramidal cell directly excites the presynaptic terminal of an inhibitory interneuron, allowing the rapid and powerful inhibition of another pyramidal cell.

Numb's function in mammalian neural progenitors has been unclear. A paper in this issue shows a crucial role for Numb in the maintenance of radial glia adherens junctions and, consequently, the integrity of the neurogenic epithelium.

Humans and other animals use environmental cues to evaluate sources of danger and to react appropriately. A new study reports that mice lacking the serotonin 1a receptor overreact to ambiguous predictors of aversive events, whereas they respond normally to unambiguous predictors, illuminating the neural bases of contingency learning.

Synesthesia, in which letters or numbers elicit color perception, could be due to increased brain connectivity between relevant regions, or due to failure to inhibit feedback in cortical circuits. Diffusion tensor imaging now provides evidence for increased connectivity in word processing and binding regions of the brain.

The olfactory epithelium is one of the few sites of adult neurogenesis, but the identity of its stem cell has been debated. A report by Leung and colleagues identifies the horizontal basal cell as this progenitor.

Szapiro and Barbour describe a new mode of neuron-to-neuron communication mediated solely by spillover of neurotransmitter that diffuses out of the synaptic cleft to bind more distant receptors on postsynaptic neurons.