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TOWARDS the end of his chummy yet dizzying state-of-the-art tour of behavioural neurobiology, Ari Berkowitz makes an important claim. Unlike, say, the pacemaker cells and synaptic complexes that together regulate the beating of the heart, we humans “simply aren’t very good at creating automatic mechanisms that take into account all the possible consequences”. He’s not kidding. Financially savvy readers may recall 2013, when the S&P 500 stock index took a $136 billion dive as trading algorithms responded instantly to a malicious tweet claiming bombs had gone off in the White House. No self-respecting nervous system would have fallen for that. Nervous systems let animals respond creatively to novel situations while never exceeding vital parameters. A heart may beat faster: it does not explode.

Explaining how they do this may be summed up in a single word – redundancy. “If we can imagine multiple mechanisms for how the nervous system controls a behavior,” Berkowitz writes, “it probably uses all of them.” This is captured in a single notorious example: a crab’s control over its digestive system. Though it involves the interplay of only 30 neurons, crab digestion varies individually, altering over time and in response to changes in water temperature. “Having a single mechanism operating would certainly improve clarity of government,” Berkowitz concedes, “but nervous systems are not concerned with clarity, only with survival and reproduction.” His metaphor of nervous system as government is a tempting stick with which to beat ideologues: what if the best government available is actually the messiest and most confusing imaginable? Simon Ings

Before now, I had never given even the slightest thought to how explorers would first have described that marvellous fruit, the pineapple. But thanks to this book, I now know that they compared it with the apricot for taste, and the artichoke for shape. Flip through this book before you head out to a summer party, and then impress your friends with first-ever descriptions of avocados, mangoes, orangutans, Aboriginal Australians and Indian acrobats. Or you could plunder the tales of some of the 17th and 18th-century European travellers, say Samuel Purchas or Captain William Dampier, whose stories make the pages so gripping.

You may already have learned how to make a love potion from Cock-Starkey’s earlier book, How to Skin a Lion: A treasury of outmoded advice. And if you have, you’re likely to be the sort of reader desperate to know who first explained the true nature of the chameleon’s colour-changing ability. You won’t be disappointed.

This book reminds us why we shouldn’t always be googling it: the search engine may give you all the information in the world, but it can’t inspire you the way this volume will. And if your child is around, read it out loud for her. You can only pep her up with the excitement of discovery – and, with luck, share your joy of discovery. Vijay Shankar

The French revolution brought new technologies and social reforms that modernised the whole world. It was fuelled in no small part by scientists, so what else could engineer Gustave Eiffel do but etch their names on his tower? A telling number lost their heads at the guillotine for doing science – and interfering in state politics. With typical wit and easy storytelling, biologist Steve Jones tells the stories of the guillotined and of those who escaped with their necks intact.

Against other accounts, such as Science and Polity in France: The end of the old regime by Charles Coulston Gillispie, Jones’s book stands thankfully light. Yet it still amply popularises physicists, biologists, astronomers, chemists and mathematicians, while not failing to show the human vanity behind so many of their actions. The story of how guillotine-enthusiast-cum-scientist Jean-Paul Marat falsely accused the chemist Antoine Lavoisier over the latter’s tobacco tax reforms, and led him to the guillotine, is as gripping as a Hollywood thriller. This was a time when sci-tech began to look closely into people’s lives and needs, while glossing over its own sociopolitical and economic impacts.

After retelling the Bible as science (The Serpent’s Promise) and guiding us through Darwin’s backyard (Darwin’s Island), Jones now makes his mark as a popular science historian. Vijay Shankar

Author and zoologist Tim Birkhead is probably most famous for successfully crowdfunding his guillemot research after the Welsh government pulled the plug on 25 years of study, or for filling York Minster with floor-to-ceiling paintings of seabird colonies. But he is also clearly passionate about eggs.

And yes, it being Birkhead, guillemots do crop up a lot in this book, but there’s so much more as well – from the reasons for hydrophobic micro-nodules on the shell of a megapode’s egg, via the purulence of hoopoe preen gland ejaculate, to the vitalness of albumin and the deep secrets of the yolk.

All this is revealed in a text that bubbles with enthusiasm. Add in the secrets of a goldcrest’s red-hot legs and, of course, why guillemot eggs are so pointy and vastly variable in pattern, and you have a book that will keep you enthralled from your morning egg to your evening quiche. A delight. Adrian Barnett

This article appeared in print under the headline “Spring-clean your mind”

Four gene mutations

Feel like you haven’t slept in ages? If you’re one of the 5 per cent of the population who has severe insomnia – trouble sleeping for more than a month – then your brain’s white matter might be to blame.

The cell bodies and synapses of our brain cells make up our brain’s grey matter, while bundles of their tails that connect one brain region to another make up the white matter. These nerve cell tails – axons – are cloaked in a fatty myelin sheath that helps transmit signals.

Radiologist Shumei Li from Guangdong No. 2 Provincial People’s Hospital in Guangzhou, China, and her team, scanned the brains of 30 healthy sleepers and 23 people with severe insomnia using diffusion tensor imaging MRI. This imaging technique lights up the white matter circuitry.

Axons unsheathed

They found that in the brains of the people with severe insomnia, the regions in the right hemisphere that support learning, memory, smell and emotion were less well connected compared with healthy sleepers. They attribute this break down in circuitry to the loss of the myelin sheath in the white matter. A study in November could be one cause for myelin loss.

The team also found that the insomniacs had poorer connections in the white matter of the thalamus, a brain region that regulates consciousness, alertness and sleep.

The study proposes a potential mechanism for insomnia but there could be other factors, says , a radiologist at Stanford. He says it’s not possible to say whether the poor connections are the cause of result of insomnia.

“This study takes us one step further in understanding insomnia and a step closer to a potential treatment,” says Wintermark. Knowing what the brains of people with insomnia look like is important if we are ever to understand the condition, he says.

Journal reference: Radiology, DOI: 10.1148/radiol.2016152038

Dogs do it. Rats do it. Even some people seem to be able to sniff out cancer and other diseases. Now we can add the humble roundworm to the list of super-smellers.

Japanese researchers have discovered that Caenorhabditis elegans worms can detect cancer in people’s urine. They are working with technology companies Hitachi and Johnan to turn the finding into a diagnostic test that can be used to catch the disease in its early stages.

“In existing tests, people must have different examinations according to the type of cancer they have”, says from Kyushu University in Fukuoka, Japan, who co-led the work. “Our odour-based test detected all nine types of cancer we tested.”

Scent of a tumour

Hirotsu and his colleague, Hideto Sonada, decided to investigate roundworms’ cancer detecting abilities after Sonada encountered a 63-year-old man with Anisakis larvae in his digestive system. This roundworm can be picked up by eating infected raw fish.

The . The case is one of 29 recorded since 1970 of roundworms attaching themselves to cancers, 62 per cent of which were when the cancer was still in its early stages.

Hirotsu and Sonada’s team wondered if the odour of the cancer lesion was attracting the roundworms. To find out, they put droplets of culture medium that cancer cells had grown in on one side of petri dishes. On the other side they put drops of fresh culture medium. When they added C. elegans to the dishes, the worms moved towards the cancer medium.

They grew other kinds of cells in the medium, such as human skin cells, but these induced no such attraction in the worms. The researchers also knocked out the olfactory sense neurons in some of the worms. This stopped them moving towards the cancer side of the dish, suggesting that the worms are indeed attracted by smell.

Sensitive sniffers

To see if they could diagnose cancer, the worms were placed in the vicinity of spots of urine from people with and without cancer. Sure enough, the worms were attracted only to the samples of the people with cancer. With samples taken from 242 people, 24 of whom had a cancer diagnosis, the worms made the correct diagnosis 96 per cent of the time, a success rate that the researchers say is better than any blood test.

The participants had various different types of cancer, and Hirotsu says the worms successfully identified cancer in all nine they were exposed to – stomach, colorectal, colon, oesophageal, pancreas, bile duct, prostate, breast and lung cancer.

The team are now investigating whether different cancer types release different odours, and whether this has an effect on the worms. They hope to have a commercial product ready by 2019. The idea would be that users send a urine sample to the company and get the results back the next day, says Hirotsu.

“It’s very surprising that the nematodes exhibited such a strong binary response to ‘cancer’ versus ‘no cancer’ urine,” says Michael Phillips at , a New Jersey-based company developing diagnostic tests based on people’s breath. He says the complexity of the tumours and the environment in which the samples are collected can contribute to confusing results. “We ought to suspend judgement on the test until it has been replicated in other labs using very careful controls,” he says.

Journal reference: PlOS One, DOI: