Category: Biology

Is this the brain’s mindfulness switch?

Thalamus small.gif

Journalists adore research that allows them to write stories along the lines of “scientists have tracked down the brain’s love HQ” or “researchers have located the brain’s god spot”. It is very satisfying to imagine that we can divide the brain into neat components with distinct functions like the parts of a car engine. We dream that one day, neuroscientists will be able to lift the bonnet (or the hood if it’s an American brain), point and say “here’s the valve that causes schizophrenia – we can readjust that with this chemical spanner. Here’s the tank that causes OCD when it overflows – we can drain that by turning this tap here. Over there are the spark plugs that we clean up to cure depression …”

Unfortunately the brain is a lot messier and more wonderful than your average motor engine, which is why we’re still standing over it scratching our heads trying to figure out how on earth it all works. It’s a tangle of connections, with myriad networks of components involved in creating thoughts, consciousness, sensations and emotions.

So it is with a mixture of excitement and wariness that I approach a study by researchers at Beijing Normal University in China that seems to point to a particular part of the brain that switches mindfulness on and off. It’s called the thalamus (shown in red on the animated gif), a pair of bulbous structures that sit at the top of the brainstem (yellow) on the midline of the brain. The thalamus plays a pivotal role as the brain’s switchboard, relaying information from all the senses apart from smell to the cerebral cortex, which is the thinking, conscious part of the brain. (more…)

Growing old stressfully: chronic stress and prematurely aged cells

Human chromosomes showing telomeres
Human chromosomes (grey) capped by telomeres (white), the structures that prevent damage to DNA with repeated cell divisions. Photograph: public domain

Forty years ago, the Whitehall Study of men working for Britain’s Civil Service famously revealed that those at the bottom of the pecking order were much more likely to die prematurely than those at the top – regardless of other risk factors such as smoking. They had higher mortality rates from all causes, but especially heart disease.

So the lowly paid doorman, whether or not he was a heavy smoker, was more likely to drop dead than the clerk sitting at his desk all day earning more money. As ever, life was deeply unfair. But what was the biological explanation for this health inequality? One theory was that the stress and lack of control over their working lives experienced by men in lowlier jobs were putting their health at risk, though how that worked physiologically was anyone’s guess. (more…)