News & Views in 2007

Two independent groups in this issue report synaptic communication between callosal axons and the NG2-positive glial precursors in the brain. Activity-dependent vesicular glutamate release from axon collaterals triggers AMPA-type currents in the precursors. This phenomenon might be involved in regulation of oligodendrocyte differentiation or remyelination.

Astrocytes modulate synaptic strength. This effect occurs, reports a new paper, because ATP-dependent vesicular release of astrocytic glutamate acts on presynaptic neuronal NMDA receptors to increase synaptic efficacy.

Sensory neurons express sets of ion channels that contribute to pain transmission. A new study finds that a sensory neuron–specific exon encodes a molecular switch that recruits other signaling pathways to N-type Ca²⁺ channels.

In the adult hippocampus, a brain region that is important for memory, new neurons are generated continuously. A study now shows that these newly generated neurons are preferentially activated during learning and recall of new memories.

A new study shows that the identity of olfactory sensory neurons in flies is regulated by Notch signaling, which divides the neurons into two classes that express specific sets of olfactory receptors and project to distinct glomeruli.

The primate prefrontal cortex is associated with cognitive operations linked to intelligence. A study in Nature now shows that prefrontal neurons represent movement sequences at an abstract level, even when not required for the task.

Humans engage in complex social interactions, including altruism. A study in this issue finds that watching a computer perform an altruistic act, earning money for charity, is sufficient to activate a brain region that has been implicated in the evaluation of others' motives and goals, suggesting that this area may be involved in detecting agency in other creatures.

Studying consciousness is difficult because asking subjects to report their awareness of a stimulus perturbs that awareness. A new paper shows that asking subjects to wager on whether their response is correct can solve this problem.

Kozlov and colleagues study how hair cells achieve their sensitivity to mechanical stimuli. They report that the hair bundle is tightly constrained to move as a unit, ensuring the concerted gating of transduction channels in hair cells.

Sleep may promote the transfer of memories from hippocampus to cortex. New work shows that experiences are replayed during sleep in both brain regions and that replay in these two areas occurs synchronously.

Is it possible to know what to do without being able to act upon this knowledge? In a recent study, Atallah et al. show clear evidence that learning a new skill and expressing it are two separate steps that can be dissociated.

A recent paper in Science reports that for Schwann cells to initiate myelination, the Par-3 polarity protein must interact with the neurotrophin receptor p75^NTR and relocate it to membrane domains of glia-axon contact.

Addicts report that opiate drugs lose their rewarding effects over time, but the molecular mechanisms underlying this effect are unknown. A study now reports that tolerance to morphine reward in rats is due to downregulation of IRS2-Akt signaling in the ventral tegmental area (VTA), the cell body region of the mesolimbic dopamine reward system.