The adult brain maintains the ability to renew itself in specific brain area. In rodents adult born neurons (ABNs) are continuously replaced in the hippocampus and olfactory bulb. We established an experimental system to test the functional role ABNs on coding of odor information. Silencing ABNs quenched the responses to odors. This was unexpected since the ABNs are inhibitory. To explain these results, we designed a computational model, and provided a mechanistic explanation to the seemingly surprising result. We conclude that ABNs sharpen odor responses by a unique network mechanism.