MRI scans show that after an eight-week course of mindfulness practice, the brain’s “fight or flight” center, the amygdala, appears to shrink. This primal region of the brain, associated with fear and emotion, is involved in the initiation of the body’s response to stress.
As the amygdala shrinks, the pre-frontal cortex – associated with higher order brain functions such as awareness, concentration and decision-making – becomes thicker.
The “functional connectivity” between these regions – i.e. how often they are activated together – also changes. The connection between the amygdala and the rest of the brain gets weaker, while the connections between areas associated with attention and concentration get stronger.
The scale of these changes correlate with the number of hours of meditation practice a person has done, says Adrienne Taren, a researcher studying mindfulness at the University of Pittsburgh.
“The picture we have is that mindfulness practice increases one’s ability to recruit higher order, pre-frontal cortex regions in order to down-regulate lower-order brain activity,” she says.
In other words, our more primal responses to stress seem to be superseded by more thoughtful ones.