Do you know that the practice of meditation, widely used in the Islamic mystic (Sufi) tradition, increases the number of gamma waves in your brain?
An experiment involving a group of Tibetan Buddhist monks revealed that meditation on compassion and love can increase the number of gamma waves in your brain.
Ed Yong, a writer for Atlantic, describes gamma waves this way: “When a crowd starts to applaud, each person initially does so to their own rhythm, but in some cases those claps can synchronize with hundreds of thousands or millions of hands striking in unison. Something similar happens in the brain. When a single neuron fires, it sends an electrical pulse down its length. But large networks of neurons can fire together, creating regular cycles of electrical activity that resemble the synchronized applause of rapturous crowd. Formally these are called neural oscillations; more colloquially, they are brain waves.” 
Scientists classify these waves based on how frequently neurons fire in a single second. If neurons fire 30 to 90 times, the waves are called gamma waves and are linked to higher mental abilities such as sensory perception and increased focus and memory. 
When focusing on love and compassion, the Buddhist monk’s brain works in a coherent manner, showing that neuronal structures fire in harmony. This phenomenon in the monk’s brain was the largest seen in humans. Neuroscientists say this could explain the heightened sense of consciousness, bliss, increased cognitive functions and intellectual acuity caused by meditation. 
 Yong, Ed. "Beating Alzheimer's With Brain Waves." The Atlantic. Dec 7, 2016. https://www.theatlantic.com/science/archive/2016/12/beating-alzheimers-with-brain-waves/509846/