How does convergence in olfactory glomeruli help animals detect faint odors?

In the olfactory system, convergence is a critical anatomical feature that enhances an animal's sensitivity to odors. Within the olfactory bulb, axons from large numbers of olfactory receptor cells that respond to the same or structurally similar chemicals all terminate at a single, discrete sphere of nerve tissue known as a glomerulus.

This arrangement allows for the pooling of neural input. Because the signals from many individual receptor cells are brought together at one site, the system can effectively amplify the input. Consequently, even when an odor is present in such low concentrations that only a few receptor cells are stimulated, the convergence of their signals onto a single glomerulus ensures that the collective effect is maximized, allowing the animal to detect faint odors that might otherwise go unnoticed.1