The brain is constantly bombarded by smells, so how does it filter and categorize the scents that define our days? "Scientists have discovered a dialogue between the bulb and the cortex conducted by rapidly firing nerve cells. 'It was originally thought that the olfactory bulb filtered and the olfactory cortex made decisions on whether something is, for example, edible,' said lead researcher Diego Restrepo, University of Colorado neuroscience professor. 'Our study says it's not quite like that. You process information on reward in the olfactory bulb, send it to the cortex and there is a dialogue between the two. Then the brain will act.'"