Health and Medical News and Resources

General interest items edited by Janice Flahiff

[Reblog] Has the brain-zap backlash begun?

A fMRI scan showing regions of activation in o...

A fMRI scan showing regions of activation in orange, including the primary visual cortex (V1, BA17). (Photo credit: Wikipedia)

From the 28 November 2014 post at The New Scientist

Stimulating the brain with electricity improves working memory, mental mathsfocused attention, creativity and could help treat depression. You can even buy DIY kits online. That’s the good news. The bad news is that the most recent investigation has found it has almost no measurable effect on the brain.

It’s a conclusion that is likely to be controversial. Over the past decade, thousands of studies have reported a beneficial effect of transcranial direct current stimulation (tDCS) on the brain, as well as on behaviour and cognition – so much so that it has become something of a hot topic in neuroscience.

The idea behind tDCS is that passing a weak current through the brain changes the electrical potential of nerve cell membranes. This alters the strength of connections between neurons, making the circuit more, or less likely to fire. It’s a tricky thing to measure directly, so any physiological effect is inferred by blood flow changes on functional MRI scans, changes in brainwaves measured by EEG, or in the strength of muscle contraction when the motor cortex is stimulated, known as an MEP.

But when Jared Horvath and his colleagues at the University of Melbourne in Australia, pooled the results of more than 100 studies reporting any or all of these measures, they found that only one was convincingly changed after tDCS. The other two were inconsistent at best.

And what are the DIY stimulation enthusiasts to make of all this? “There are two options,” says Horvath. “The first is that tDCS is doing something, but we don’t know what, so take that on board. The second is a bit more innocuous: tDCS might not be doing anything to the brain, so have a good time, but temper your expectations.”

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November 29, 2014 - Posted by | Medical and Health Research News | , ,

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