Here's what happened in two instances: We're comparing two strains of flies, each of them having about 100 light-addressable cells in their brains, shown here in green on the left and on the right.
Ecco cosa e' successo in due casi. Mettiamo a confronto due famiglie di mosche, ognuna delle quali ha circa 100 cellule fotosensibili nel cervello, qui' indicate in verde a destra e a sinistra.