From brains to bottom wipers, here's the week's best science news

This week was all about ancient poo sticks, gut bacteria and brains. Oh, ok, maybe not all about those things. But mostly. Composite: Various

This week’s biggest stories

I used to believe that there is nothing better in life than an ancient oriental poo mystery. I was wrong. The best thing is the answer to an ancient oriental poo mystery, provided ithis week by scientists from Cambridge, who have analysed 2,000-year-old “personal hygiene sticks” found on the Silk Road. If bottom wipers aren’t your thing (really?!) then it’s possible the discovery that the evolutionary history of the bacteria in your guts predates the appearance of humans is still a bit too, um, internal for your liking. In which case, let us be more cerebral, and celebrate the fact that scientists have updated the map of the human brain, revealing that it has at least 180 different regions that are important for language, perception, consciousness, thought, attention and sensation. And interest in poo stories, I’d imagine ...

More news from Guardian Science | Sign up to Lab notes

___

Straight from the lab - top picks from our experts on the blog network

A handlebar moustache and a dose of strychnine and they were ready to go ... competitors in the 1904 Olympic marathon. Photograph: Popperfoto/PPP

The cocktail of poison and brandy that led to Olympic gold | Notes & Theories

Substances only get banned after an athlete is found to have used them or if their potential to enhance performance is obvious. The reason strychnine is on the banned list is because at least two Olympic athletes (that I know of) have been crazy enough to take it.

The perils of being a powerful white man | Brain flapping

But why? Why do powerful, wealthy types so often perceive minor inconveniences as existential threats? One possibility is that a very privileged life is something you get used to. The brain is a very adaptive organ and quickly finds even initially alarming things familiar and predictable, so whatever your regular experiences are, they become ‘the norm’.

Invasive lionfish have reached the Mediterranean. Luckily they’re tasty ... | Notes & Theories

If the lionfish invasion across the Atlantic is anything to go by, their spread will be rapid and uncontrollable - and there isn’t a ‘magic bullet’ that can remove the fish from across their new range.

Visit the Science blog network

___

Alex Bellos’s Monday puzzle

Jetting off somewhere soon? Well here’s a useful puzzle for people going on their summer holidays.

Tie your shoelace here ... or is there somewhere better. Efficiency is everything, people. Photograph: Alex Segre / Alamy/Alamy

Did you solve it? Can you settle back into your seat to browse the film selection now that you know the answer?

__

Science Weekly podcast

Us and Them: are we biologically primed to fear outsiders? Photograph: Roberto Schmidt/AFP/Getty Images

Is there a biological basis for human division? And can science help us bridge the divide when conflicts arise? For this week’s podcast, Ian Sample is joined in the studio by social psychologist Professor Miles Hewstone and primatologist Dr Kit Opie to discuss group behaviour and the divisions that define us as human.

_____

Eye on science - this week’s top pictures

The large ichythosaur Opthalmosaurus swimming in the shallows is joined by some smaller pterosaurs floating on the surface. Photograph: Dr Mark Whitton

In his new book Recreating an Age of Reptiles, artist and palaeontologist Dr Mark Witton explores the issues around trying to bring extinct animals and their environments back to life. He gave us preview of his recreation of the world of the dinosaurs.