The damage done to the brain by drugs is tricky to measure, but I spoke to a team in New York which can map the wrecked blood vessels left behind in the cortex of mice by cocaine – sometimes it constricts the vessels so much that blood flow could hardly be detected at all. The same method might be good for assessing anti-cancer treatments too.

And: finding practical uses for lenses based on the design of insect eyes has been a live topic for a while, but what happens if you go the opposite way and make a fly’s eye emit light instead? A group in Pennsylvania gave it a try.