Friday, February 24, 2017


Mice that meditate? Well, why not? In this case, it was a scientifically-designed experiment to assess the effect of theta brainwave activity. Meditation increases theta wave activity, even when people are no longer meditating. The experiment involved creating what was probably the world’s first mouse model of meditation, using light to trigger brain activity similar to what meditation induces. The results were illuminating.

Many previous studies have shown that meditation reduces anxiety, lowers levels of stress hormones and improves attention and cognition. In one study of the effects of 2 to 4 weeks of meditation training, psychologist Dr Michael Posner, pictured left, of the University of Oregon and colleagues discovered changes in the white matter in volunteers’ brains, related to the efficiency of communication between different brain regions. The changes, picked up in scans, were particularly noticeable between the anterior cingulate cortex (ACC) and other areas.

The ACC regulates activity in the amygdala, a region of the brain that controls fearful responses and other emotional reactions as well as playing a primary role in the processing of memory and decision-making.

Posner’s team concluded that the changes in white matter could be responsible for meditation’s effects on anxiety. What was not known was how meditation could alter the white matter in this way. Posner theorized that it was related to changes in theta brainwaves. To test the theory, the team used what is known as optogenetics, that is, genetically engineering certain cells to be switched on by light. In this way, they were able to use pulses of light on mice to stimulate theta brainwave-like activity in the ACC.

Mice received 30 minutes of this stimulation for some 20 days. Before and after the treatment, the mice underwent behavioural tests to measure anxiety. When placed in a box with a light area and a dark area, fearful mice spend more time in the dark. The team found that mice that received theta wave stimulation were less anxious than mice given light pulses that induced other kinds of brainwaves, or who had no treatment at all.

Posner says this mirrors meditation’s ability to lower anxiety in humans and supports the involvement of theta waves in this effect. The team is still studying the white matter in the mouse brains and hope to report on any changes later.

: Weible A P, Piscopo D M, Rothbart M K, Posner M I, and Niell C M. ‘Rhythmic brain stimulation reduces anxiety-related behavior in a mouse model based on meditation training.’ PNAS 2017; published ahead of print, Feb 21, 2017, doi:10.1073/pnas.1700756114


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