Spontaneous neural activity in the developing ant olfactory system

Spontaneous neural activity, a key aspect of mammalian neurodevelopment, has been observed in the developing olfactory systems of ants. Unlike fruit flies, whose antennal lobe glomeruli form without functional odorant receptors, ants possess an expanded olfactory system that demands functional receptors for proper development. This led researchers to investigate whether ants, similar to mammals, rely on spontaneous neural activity.

Using live calcium imaging in translucent pupae of the clonal raider ant Ooceraea biroi, scientists examined the activity of developing olfactory sensory neurons (OSNs). They found that these OSNs display spontaneous calcium transients from the earliest stages of glomerulus formation. As the development progresses, the activity undergoes changes, becoming slower with longer calcium events and fewer peaks per cell.

A distinct mode emerges as the pupae near eclosion, characterized by rhythmic, sawtooth-shaped calcium events that synchronize activity between OSNs in both antennae.

These stage-dependent spontaneous activity patterns suggest that the complex ant olfactory system may utilize a developmental logic more similar to mammals than to the simpler system found in fruit flies.