Volume 10 Issue 1, January 2007

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.

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.