Flies prefer fizzy drinks

The exposed brain of a fly with a superimposed image of fluorescently labeled taste neurons in the region called the subesophageal ganglion. The diagram at right shows how the three identified taste cells on the fly's proboscis – sweet (green), bitter (red) and carbonated (blue) – send their axons through the proboscis to the brain. The bright green spot in the brain on the left correspond to the red halo in the right photo. (Kristin Scott/UC Berkeley, courtesy of Neuron)