Our Greater Brain

• The lumbosacral plexus is the nerve network that leaves the lower spine and serves the pelvis, hips and legs. The spinal cord thickens here, at the lumbar enlargement, to handle the legs.
• The whole spinal cord holds on the order of 100 million neurons. Published estimates vary.
• The soles of the feet are among the most densely nerve-supplied skin in the body. Together with the stretch sensors in muscles and joints, they feed the constant posture and balance loop that grounding depends on.
• The HeartMath Institute's Global Coherence research reports that the earth's own resonant frequencies sit close to those of the human heart, brain and nervous system, and proposes that the earth's magnetic field carries information linking living systems. Grounding is our side of that connection.

In practiceBear Resting: hands at navel height facing the root, knees soft, weight spread evenly across both feet, front and back.

• The enteric nervous system lines the gut wall with 200 to 600 million neurons, more than the spinal cord. It can run digestion on its own, even without input from the brain.
• More than 90% of the body's serotonin is made in the gut, along with an estimated half of its dopamine.
• In Daoist and martial arts practice, the dantian is the body's storehouse of energy and its center of mass.

In practiceBear Rising: cupped hands in front of the belly, front and back of the body relaxed, energy rising to this level only.

• The celiac plexus, the anatomical solar plexus, is a cluster of autonomic ganglia around the main artery to the stomach, liver, pancreas and intestines.
• It belongs to the autonomic nervous system, the part that shifts the body between alert and rest without being asked.
• The diaphragm, our main breathing muscle, arches just above it. In 1907 the surgeon Byron Robinson wrote a whole book on it, The Abdominal and Pelvic Brain.

In practiceHeron Rising Moon: weight on the right foot, left heel resting at the right ankle, cupped hands facing the solar plexus.

• The heart brain. About 40,000 neurons form a network of ganglia in the heart itself. It can sense, process and respond on its own, which is why researchers call it a brain on the heart.
• The heart leads the conversation. Most of the fibers in the vagus nerve carry signals up to the brain, and more of those come from the heart than from any other organ. The heart sends more information to the brain than the brain sends to the heart. It talks four ways: through nerves, hormones, the pulse wave and its electromagnetic field.
• The heart is also a gland. It makes atrial natriuretic factor, nicknamed the balance hormone, which calms stress responses. It also makes oxytocin, the bonding hormone, at levels similar to the brain.
• The strongest field in the body. The heart's electrical field is about 60 times stronger than the brain's, and its magnetic field more than 100 times stronger. Instruments can detect it about three feet from the body.
• Heart coherence. When the heart rhythm settles into a smooth, even wave, rising and falling about once every ten seconds, the HeartMath Institute calls this coherence. Breathing, blood pressure and brain rhythms fall into step with the heart. Coherence is linked with calm, clearer thinking, emotional balance and better performance.
• Why slow breathing helps. Breathing in for about five seconds and out for about five matches that ten-second rhythm, so it guides the heart into coherence. Adding a warm feeling such as appreciation or care holds it there longer. HeartMath teaches this as heart focus, heart breathing and heart feeling.

In practiceHeron Rising Sun: heron stance, cupped palms facing the heart, hands stacked, right hand outside the left, about 4 to 6 inches between the hands and from the left hand to the chest. Shoulders, knees and eyes relaxed.

• The vagus nerve (cranial nerve X) runs from the brainstem down through the neck to the heart, lungs and gut.
• About 80% of its fibers are sensory: they carry news from the heart and gut up to the brain. Only a minority carry instructions down.
• Voice, breath and swallowing all pass through this narrow gateway, which is why the throat links the body's centers above and below.
• The vagus is the main highway of the heart's conversation with the brain, so the throat center carries the heart's messages upward.

In practiceHeron Rising Song: heron stance, cupped hands toward the throat, the felt ball of energy resting there.

• The thalamus relays almost every sense to the cortex. The hypothalamus regulates body states such as temperature, hunger and stress. The pineal gland makes melatonin, which sets the sleep rhythm.
• The cerebellum, at the back and base of the skull, holds about 69 billion neurons, around 80% of the brain's total. It governs balance, rhythm and smooth coordination: the part of the brain most at work in slow, flowing movement.
• Signals from the heart arrive here within a fraction of a second of each beat and shape attention, perception and emotion. HeartMath research reports that a coherent heart rhythm supports clearer, steadier thinking.

In practiceHeron Rising Peace: heron stance, cupped palms facing the center of the head, hands stacked, attention resting in the center of the head. Peace here means relaxed and free of stress.

• The cerebral cortex is the folded outer layer of the brain, about 19% of its neurons. Its front portion directs and holds attention.
• In this practice the crown is where awareness opens beyond the body, toward the consciousness that is always with us. Science doesn't locate consciousness in any one place, so this is where the anatomy hands over to experience.
• HeartMath's research suggests coherence doesn't stop at the skin: one person's heart rhythm has registered in another's brain waves nearby, and their Global Coherence work explores how many coherent hearts together may affect the wider world.

In practiceHolding Heaven's Bridge: both hands above the head, cupped toward each other.