[1] They receive input from the receptor cells of the olfactory epithelium found in areas of the nose able to sense smell.
Projection neurons send the signals from the glomeruli deeper into the brain.
The actual signal sent through these projection cells has been sharpened or filtered by a process called lateral inhibition.
Projection neurons therefore transmit a sharpened olfactory signal to the deeper parts of the brain.
Tufted cells project onto the anterior piriform cortex.