The technique is to put the breath under surveillance whilst lying down (or sitting) completely still. During that 8 - 12 minutes the breath will go through all kinds of reactions (deep, shallow, erratic, gasping, etc, etc) until it eventually settles into a soothing rhythm. When the rhythmic breath has been established the process of telencephalisation has been completed.
In recent decades scientists have explored and experimented re the effects of meditation on the brain, here is one article, in part:
"A number of studies have linked meditation practice to differences in cortical thickness or density of gray matter. One of the most well-known studies to demonstrate this was led by Sara Lazar, from Harvard University, in 2000. Richard Davidson, a neuroscientist at the University of Wisconsin, has led experiments in cooperation with the Dalai Lama on effects of meditation on the brain. His results suggest that long-term, or short-term practice of meditation results in different levels of activity in brain regions associated with such qualities as attention, anxiety, depression, fear, anger, the ability of the body to heal itself, and so on. These functional changes may be caused by changes in the physical structure of the brain."
Read whole article, at: https://en.wikipedia.org/wiki/Neuroplasticity