Key facts about your brain

• Shaped by evolution, especially of emotional and relational capacities; for example, the bigger the primate social group, the bigger the brain
• 3 pounds, 1.1 trillion cells, including 100 billion “gray matter” neurons
• Always “on” – 2% of the body’s weight uses about 25% of its oxygen
• Average neuron has about 5000 connections (synapses), 500 trillion in all
• Synapses fire 1 to 100 times a second; quadrillions of synapses activate each minute
• Brain regions linked by neural pulses synchronized within a few milliseconds
• Highly interconnected network full of circular loops: awareness of awareness . . .
• Number of possible brain states: 1 followed by a million zeros
• The most complex object known in the universe

Your mind changes your brain

• Both temporarily, in electrochemical waves lasting mere milliseconds, and permanently, as existing synapses get strengthened and new ones get made
• As circuits get used, they strengthen their connections; “neurons that fire together, wire together.”
• Your experience matters, leaving an enduring trace behind.
• London taxi drivers have thicker regions that create visual-spatial memories.
• Mindfulness and concentration meditations activate different parts of the brain.

Your brain changes your mind

• Brain activity generates mental activity (mostly forever outside awareness).
• Trauma shrinks the hippocampus, which becomes less able to create new memories.
• More active left frontal lobes foster positive emotions.

You can use your mind to change your brain to change your mind for the better.

In just one example, mindfulness practices:

• Trigger patterns of neural pulsing that produce relaxed alertness
• Activate positive emotion circuits, building resilience and resistance to depression
• Increase serotonin, a neurotransmitter that supports mood, sleep, and digestion
• Thicken the anterior cingulate, strengthening attention and self-observation
• Thicken the insula, strengthening internal sensing and empathy for others
• Stimulate the parasympathetic nervous system (PNS) for relaxed well-being
• Strengthen the immune system, improve cardiovascular health, dampen chronic pain