Several changes occur to the brain during meditation. Scientists have used magnetic resonance imaging, or MRIs, to determine exactly how meditation affects the brain. Brainwave characteristics are altered, portions of the cortex physically thicken, the amygdala is less active, and the hippocampus becomes more active. With regular mediation practice, some of these changes remain even after the meditative state is left.
Electrical activity changes radically in the brain during meditation. Beta waves, at roughly 15 to 30 cycles per second, decrease considerably during meditation. They are involved with logical thinking, dialogue, and many if not most of the daily activities of life. Theta waves, at between 4 and 7 cycles per second, are associated with daydreaming, high creativity, and meditative states. They increase during meditation.
Cycling at 7 to 13 cycles per second, alpha brainwaves are present during relaxed states and signal an absence of stress or anxiety. Alpha waves increase in the brain during meditation. As these waves contribute to the ability to learn new information, meditating over a period of weeks or months will increase the practitioner’s ability to absorb new information.
A person who is meditating is in a very focused, alert, and deeply peaceful state. Breathing and heartbeat both slow, and blood pressure drops. The practitioner’s focus turns inward, and there are very specific changes that result in the brain during meditation. The cortex, which is the reasoning center of the brain where self-consciousness, emotion, and logic live, largely shuts down. Instead, the parts of the prefrontal cortex and right anterior insula that are involved with sensory information processing and noting details physically thicken due to a widening in the blood vessels.
Stress is not only unpleasant; it physically changes the brain by causing hippocampus neurons to reduce in size. The hippocampus is that part of the brain that allows memory, contributes to a sense of well-being, and supports learning. Through long-term meditation, the reduction of stress results in the hippocampus rebuilding itself. Not only does the hippocampus gain brain matter, but the amygdala, the part of the brain that handles anger, sorrow, and anxiety, reduces during meditation. This gives stress and unpleasant emotions a double whammy.
Meditation literally has the power to rewire the brain. People who struggle with depression, have anger issues, or suffer from anxiety attacks can, through focused meditative practice, create new and healthier habits of thought and feeling and actually form new pathways in the brain. A healthy brain also contributes to a healthy body. Researchers have noted that people who participate in regular meditation over a long period of time are less likely to suffer from chronic disorders. For those who do, the discomfort is minimized through meditation.