Local olfactory nerve stimulation triggers patchy activation of columns across rat olfactory bulb

Columnar organization is a hallmark of neocortical sensory areas, most prominently in primary somatosensory and visual cortex. In the olfactory bulb, the existence of a vertical columnar organization of circuits associated with glomerular input channels has been implicated by various approaches. Here, based on activity-dependent labelling and tissue clearing, we provide direct evidence for functional bulbar columns formed by mitral cells and granule cells that display a uniform morphology.