Cover legend: The blue light illuminates a slice of an adult mouse olfactory bulb. Blue DAPI staining reveals different cellular layers of the bulb. Green cells are a cohort of adult-born neurons that was virally transfected with ChR2 coupled with YFP. Red cells are immature neurons that were labeled with doublecortin immunostaining. Optical stimulation was used to remotely control the spiking activity of adult-born neurons. The action potentials in the blue trace were evoked with brief optical stimulation of a granule cell expressing ChR2. The gray trace represents inhibition of sustained firing of a neuron postsynaptic to optically stimulated adult-born neurons. The yellow trace illustrates GABAergic currents in a cell postsynaptic to a light-stimulated ChR2 + granule cell. For more information, see the article by Bardy et al. in this issue (pages 17023–17034).).