Volume 6 Issue 11, November 2003

How does the brain orchestrate the integration of new neurons into mature circuitry, without disrupting those circuits in the process? Mizrahi and Katz provide a new perspective on how the brain manages this dilemma, by showing that the dendritic backbone of mitral/tufted cells in the adult olfactory bulb is remarkably stable despite learning and neuron turnover.

In C. elegans, social and solitary feeding behavior can be determined by a single amino acid change in a G protein–coupled receptor. A new study identifies ligands for this receptor and suggests how changes in behavior evolve at the molecular level.

A new study in this issue demonstrates that two GABAergic motor neurons in C. elegans are excitatory at target muscles because GABA activates a ligand-gated cation conductance, which is structurally similar to several other ligand-gated channels.

The auditory cortex, once thought to be a passive detector, is now caught in the act of reshaping the frequency sensitivity of its neurons to intercept target sounds that are significant for a behavioral task, suggesting tuning properties can change 'on-line'.

New findings reveal that people sniff when imagining odors and that sniffing can modify the pleasantness or unpleasantness of the mental image. The work parallels findings in other systems and suggests common neural principles for mental imagery.