Volume 8 Issue 4, April 2005

The outer photoreceptors of Drosophila project to their targets in an extremely intricate pattern. Prakash et al. in this issue show that homophilic adhesion via N-cadherins is an essential part of the axon guidance mechanism in this system. The new results suggest that axons respond to the level of N-cadherins, and not to any combinatorial cadherin code, as had been postulated previously.

A new paper quantifies the dependence of synaptic transmission on transient local changes in internal calcium, examining the equilibrium dynamics of the calcium sensor for exocytosis and its contribution to short-term changes in synaptic strength.

A new study shows that amyloid plaques tagged with fluorinated ligand can be detected with ¹⁹F MRI in transgenic mice. The superior signal to noise of this technique is a major step toward visualizing the histopathology of Alzheimer disease in living patients.

A report in Nature describes a physiological screen used to identify a previously unknown chemical signal in mouse urine. The chemical's selective response in the olfactory bulb raises interesting questions for how socially relevant odors are encoded.

A new model by Machens et al. proposes a mechanism by which prefrontal cortex neurons can do two jobs that are normally thought to occur independently. In a stimulus comparison task, these model neurons both cast votes for a stimulus and make decisions.