There’s a new twist in mental health. People with depression seem three times as likely as those without it to have two brain lobes curled around each other.

The brains of people with depression can be physically different from other brains – they are often smaller, for example – but exactly why that is so remains unclear.

In humans, some studies point to changes in the size of the hippocampi, structures near the back of the brain thought to support memory formation.

“There are so many studies that show a smaller hippocampus in almost every psychiatric disorder,” says , a neuroscientist at the Monash Alfred Psychiatry Research Centre in Melbourne, Australia, who led the latest work looking at brain lobes. “But very few can actually show or hypothesize why that is.”

Mind-bending research

Maller thinks he has stumbled on an explanation. He had been using a brain stimulation technique known as transcranial magnetic stimulation as a therapy for antidepressant-resistant depression.

This involved using fMRI scans to create detailed maps of the brain to determine which parts to stimulate. While pouring over hundreds of those maps, Maller noticed that many of them showed signs of occipital bending. This is where occipital lobes – which are important for vision – at the back of the brain’s left and right hemispheres twist around each other.

So he and his colleagues scanned 51 people with and 48 without major depressive disorder. They found that about 35 per cent of those with depression and 12.5 per cent of the others showed signs of occipital bending. The difference was even greater in women: 46 per cent of women with depression had occipital bending compared with just 6 per cent of those without depression.

Reduced activity

, a clinical psychiatrist at Columbia University in New York City, says the anatomical findings may relate to findings by his team and others which show reduced electrical activity in the occipital brain regions of patients with major depressive disorder, although the mechanism at work is still unclear.

Maller thinks the brain twisting could be the result of abnormally developed ventricles, channels that carry cerebrospinal fluid through the brain.

The twisted occipital lobes could in turn be putting pressure on the hippocampus, he says, preventing it from growing properly and ultimately upping the chances of someone developing depression.

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Resting state networks (RSNs), sometimes called the “dark energy of the brain”, are patterns of low-frequency brain activity that are constantly active, even when a person is asleep.

Activity in one RSN, the default mode network, drops when someone is engaged in a task, and it may be involved in introspective activities like envisioning the future – what some would call a facet of consciousness.

Fully formed

Previous studies suggest that this network only fully develops during childhood, but and colleagues at Imperial College London have now shown it is fully formed at birth.

The finding came as the team investigated the relationship between RSNs and cognitive functions. They scanned the brains of 70 babies born up to three months early, whose development served as a proxy for fetal development. While rates of progression varied, RSNs for vision, touch, movement and decision-making were largely complete by 40 weeks, as was the default mode network.

The fact his team found the default mode network in newborn babies suggests that “either being a fetus is a lot more fun than we remember”, as we were able to lie there thinking about the future, or current understanding of what these networks do is mistaken, says Edwards.

Neurologist of Washington University in St Louis, Missouri, who was not involved in the research, is wary of drawing conclusions. While structures like the default mode network may make consciousness possible, he says, they do not define it. However, the finding that newborn brains are more developed than previously thought means the research may ultimately help diagnose and treat neurological conditions like cerebral palsy, says Raichle.

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Politics is an emotional business, but it seems that subtle physiological reactions have political consequences, too. For example, Douglas Oxley at the University of Nebraska in Lincoln discovered that political conservatives react more strongly to shocking images and sudden noises by sweating more and blinking harder, compared with liberals.

To find out whether such physiological responses were also related to political action, , also at Nebraska, and colleagues asked 51 people about their degree of political participation, such as whether they voted or had ever contacted government officials.

The researchers then ran tiny currents across the volunteers’ skin to monitor how much they perspired as they looked at pictures of sunsets, cute animals, fist fights and vomit – pictures already known to evoke an automatic sweat response.

The team found that the more a person sweated in reaction to the pictures, the more likely they were to actively participate in politics – with those whose perspiration increased the most around twice as likely to participate in political action as those who perspired the least.

Sweating success

Perspiration, Gruszczynski says, was as good a match for political participation as a person’s level of education – a stalwart measure in this field of research.

Exactly why our sweat may reflect our involvement in politics is still unclear, but the finding adds to mounting evidence that points to a biological, and perhaps genetic, basis for political views and actions.

The results were presented last month at the annual meeting of the .