Volume 8 Issue 3, March 2005

How activity-dependent synaptic plasticity shapes the development of inhibitory synapses has remained unclear. In this issue, Gillespie et al. show that in the developing rat auditory system, inhibitory synapses transiently co-release glutamate. The consequent activation of postsynaptic NMDA receptors may be critical for the plasticity mechanisms that determine tonotopic sharpening.

Stem cells transplanted after spinal cord injury mostly generate astrocytes, which can promote aberrant sprouting of sensory neurons, leading to allodynia. Making cells produce more oligodendrocytes reduces allodynia and improves functional recovery.

Having control over a stressful situation can reduce its negative physiological and cognitive consequences. In this issue, a new study in rats suggests that descending inputs from the prefrontal cortex to the serotonergic midbrain signal the controllability of stress.

A recent study of an Olig1 knockout mouse concludes that remyelination after injury may occur by a different mechanism from myelination during normal development, but another report suggests that this mouse model should be interpreted cautiously.

In a technical tour de force, Okhi et al. image the activity of thousands of visual cortical neurons in vivo at a single-cell resolution, and examine their orientation and direction selectivity. Their results show that cortical maps can be built with single-cell precision.