chapter six

The Brain and
Nervous System

The nervous system is a complex and fascinating frontier, one of the final frontiers of human discovery and doubtless a mystery that may never be completely solved. For our purposes here, the central nervous system will be comprised of the brain and the brain stem, and the peripheral nervous system is the complex of nerves that allow us to sense what is in the world around us and to respond to these sensory observations with physiological and behavioral responses. All together, the nervous system allows us to think, reason, create, remember, and even to keep us safe, since the hormones and glands associated with quick action under threat are directed by the nervous system.

The largest (and heaviest) part of the brain is the cerebrum, the wrinkly grey matter that is the “bulk” of the brain. Commonly removed by Egyptian mummifiers as extraneous matter, the brain is now understood to be Grand Central Station for thought. The cerebrum, in particular, controls voluntary muscle movement as well as reasoning and deductive skills. Below the cerebrum lies the cerebellum, a smaller organ that controls body balance and the interplay between sensory organs and muscular activity. Beneath the cerebellum lies the brain stem that connects the brain to the spinal cord; the brain stem controls involuntary movements such as lung contraction and breath, heart muscle contraction, internal muscle contraction (of the stomach, the small intestine, and the large intestine), and other so-called reptilian activities that must be achieved without our consciously thinking about them.

Our brains have about a hundred billion nerve cells, or neurons, and more than a thousand trillion (10 to the 15th) connections between them. It’s an incredibly complex (and miraculous) system that enables humans to send thought signals to affect actual movement and action. A neuron is part of a long chain of neurons. Each is separated by a synaptic cleft, the tiny space between neurons, the “yard between houses.” This space is where much of the action happens—especially the action that can be affected by drugs and herbal medicines. At the very end of each presynaptic neuron sit little pouches full of neurotransmitters—the chemical messengers that stimulate the process of electrical transmission of information. Think of these as the kids in each house who want to go play in the yard. Their game is that they bunch up by the door, waiting for a special signal. When they get the signal, many of them run out the door and into the yard. The goal is to get to the other side—to the door of the next house— and send the signal along to the kids that are waiting at the next house.

There are many types of neurotransmitters that wait at the presynapse, including amino acids (glutamate), peptides (endorphines), and monoamines. Monoamines are responsible for attention, cognition, and emotion, and they include acetylcholine, serotonin, dopamine, noradrenaline, histamine, epinephrine, and norepinephrine. When an electrical signal comes down the axon (sending arm) of the neuron, its action potential stimulates the release of a particular neurotransmitter from its pouch. The neurotransmitter—say, the monoamine serotonin—expels from the pouch into the synaptic cleft. It then does one of several things:

1. It stays in the cleft, waiting.
2. It returns to the pouch in the presynaptic neuron.
3. It gets “eaten” by an enzyme (monoamine oxidase).
4. Or, it succeeds in traveling across the cleft to the next (postsynaptic) neuron. Here, it will either attach to a receptor and trigger an electrical impulse, or it will reach its final destination, such as a muscle, and trigger a muscle contraction.

The synaptic cleft is the place where herbs have a great potential for making a difference. One way they do this is by being a monoamine oxidase inhibitor.

Monoamine Oxidase Inhibitor

If the neurotransmitters (monoamines) are the kids playing from one house to the next, the monoamine oxidase (MAO) is the kidnapper that snatches them out of the yard. MAO is the enzyme that breaks down neurotransmitters, taking them out of action and keeping them from reaching the next neuron. The signals (for happiness, joy, peace, serenity, muscle control, etc.) stop.

MAO-A breaks down serotonin, melatonin, epinephrine, norepinephrine, and dopamine. MAO-B breaks down dopamine, phenethylamine, and other trace amines.

The MAO-Inhibitor (MAOI) is the police officer that stops the kidnapper. MAOIs patrol the synapse and keep the oxidases from destroying neurotransmitters; as a result, the signals continue to the next neuron. The alkaloid harmaline is an example of a plant-based MAOI, particularly against MAO-A, which is why herbs with harmaline can be effective against depression. The herbs passionflower, Syrian rue, and nutmeg contain harmaline. Other apparent herbal MAOIs are turmeric, kava kava, and ayahuasca.

Serotonin Reuptake Inhibitors

Another chemical that can stop the “game” of the neurotransmitters is one that “reuptakes” the neurotransmitter back into the neuron. If the monoamine is the kid running from one house through the yard to the next house, imagine the chemical as the grandma who yells, “Child! Get back in this house.” The child reluctantly obeys, returning to the house; the monoamine is “reuptaken” into the neuron. This stops the progression of the electrical impulse moving across the synapse to the next neuron. (Monoamines can also return naturally to their “home” neuron.) The common result: depression.

But if you put a lock on the door, so to speak, the monoamine cannot return. This allows the neurotransmitter to stay in the synapse longer to fulfill its role and continue the electrical impulse. Herbs and drugs that “put the lock on” are called Selective Serotonin Reuptake Inhibitor (SSRI) because they inhibit the monoamine from returning. These likely include St. John’s wort and licorice, though research on St. John’s wort is contradictory. 29

Myelin Sheath Protectors

Finally, some herbs help support the production of the myelin sheath, which is the fatty tissue that surrounds the neuron’s axon, promoting the transmission of the electrical information. The myelin sheath insulates the axon in intervals, keeping the sodium and potassium from “leaking” out of the axon and allowing the action potential to jump from one Node of Ranvier (action site between the sheaths) to the next, increasing the rate of transmission. In other words, the better the myelin sheath, the faster the signals move from the brain to the body.

A lack of myelin sheath is the basis of multiple sclerosis (MS), a disease in which the body’s own immune system actually attacks and dismantles the sheath around the neuron in the central nervous system, causing scar tissue to develop and disrupting muscle control, vision, speech, and voluntary movement. Amyotrophic lateral sclerosis (ALS), also called Lou Gehrig’s disease, occurs when the nerve cells die completely, causing an atrophy of the muscles. Certain herbs are being researched for their potential role in protecting the myelin sheath and easing symptoms associated with MS and ALS. Cinnamate, a compound found in cinnamon, storax (Liquidamber orientalis or benzoic resin), and shea butter, appears to block lactate transport, which can ease muscle fatigue for symptomatic relief.

More directly, turmeric may be of assistance in protecting the myelin sheath. In 2002, the Journal of Immunology reported the ability of curcumin, the so-called “active” ingredient in turmeric root, to substantially reduce the inflammatory demyelination response in mice afflicted with EAE, the mouse version of multiple sclerosis. 30 More recently, curcumin is the focus of researchers at Vanderbilt University who recognize the plant’s ability to destroy the beta-amyloid plaques of Alzheimer’s disease but who have been stymied by curcumin’s inability to cross the blood-brain barrier. 31 To overcome this obstacle, Vanderbilt and Japanese researchers developed a curcumin analog that can be made into an aerosol and inhaled, bypassing the blood-brain barrier. Their studies in mice suggest that aerosol applications might be helpful for humans suffering with either Alzheimer’s, MS, and related diseases of myelin sheath degeneration.

Parkinson’s Disease

A healthy supply of dopamine supports balance, muscle control, impulse control, attention, wakefulness and energy, and assertiveness. Too little leads to anxiety, frustration, violence, and muscle tremors. It also leads to Parkinson’s disease. In PD, the neurons that produce dopamine die off or stop their use of dopamine, affecting the movement of the hands and legs and even speaking and swallowing. Ashwagandha, turmeric, astragalus, and codonopsis warrant more study for their effects on Parkinson’s disease; the following herbs are also worth mentioning:

• velvet bean (Mucuna pruriens): a study of the powdered bean of this vine lists velvet bean as a “natural source of L-dopa” and reports that individuals in the trial experienced rapid onset of antispasmodic action and a longer interval between needed doses. 32
• griffonia (Griffonia simplicifolia): this plant’s seeds yield 5-Hydroxy-L-tryptophan (5-HTP), which is extracted in laboratories from this woody shrub native to West-Central Africa. The chemical extract has numerous studies attributing to it activity against both Parkinson’s and depression. 33
• corydalis (Corydalis cava): more traditionally used as a sedative, hypnotic, and analgesic, the roots of this herb are gaining popularity for use in Parkinson’s disease, as its complex alkaloids show antispasmodic activity. 34 Some herbalists use the herb to ease spasms and pain in the pelvis, especially for women with chronic pelvic pain (CPP). 35

Parkinson’s Disease Formulas

A Formula for Muscle Spasms in Parkinson’s

• 2 parts turmeric
• 1 part astragalus
• 1 part velvet bean
• 1 part St. John’s wort

Calming and Nervine Herbs

Another neurotransmitter is noradrenaline. This stress hormone is produced by the sympathetic neurons of the heart and stimulates myocardial contractions. It also stimulates stress-related behavioral and physiological responses to danger, which can result in increased heart rate, shallow breathing, increased dispersal of glucose throughout the body, increased dispersal of blood to skeletal muscles and constriction of skeletal muscles, dilation of pupils, and increased blood flow to the brain. These are commonly called the fight-or-flight responses and are essential to the survival of an organism under pressure or attack.

Many plants that contain chemicals that produce exactly the opposite effect, calming the body, relaxing the muscles, easing the breathing, calming the mind—and they’ve been used traditionally to reverse this process in acute situations and to prevent it from happening in chronic-stress situations. Consider:

• motherwort (Leonurus cardiaca): As its name suggests, heart of the lion has been used as a cardiotonic to strengthen the heart. This bitter-tasting herb is also a spasmolytic to reduce the angry effects of tight, tense muscles. The leaves contain the alkaloid leonurine, a vasodilator that allows greater flow of blood through the vessels and eases the pressure on the heart, reducing blood pressure. This lessens pressure on the peripheral nervous system, as well, relieving feelings of frustration, tension, and panic. Motherwort has the potential to mitigate or reverse the effects of noradrenaline.
• skullcap (Scutellaria lateriflora): Long appreciated as a nervine tonic, skullcap is used for anxiety, headache, and insomnia—all effects of the production of noradrenaline from acute or chronic stress. The use of skullcap has been contested, however, by herbalists such as Varro Tyler, who point to studies in which there was no relief noticed for the use of the herb. Other studies have shown a benefit and a distinct difference between American skullcap (S. lateriflora) and Chinese skullcap (S. baicalensis), with American skullcap leaf acting as a sedative and nervine tonic, and Chinese skullcap root acting as an antispasmodic and anti-inflammatory, especially useful for headaches. It may also have some anti-cancer properties. Both forms of skullcap have been subject to dishonest substitution usually with germander (Teucrium chamaedrys), a hepatotoxic.
• passionflower (Passiflora incarnata): traditionally for anxiety, insomnia, seizures, and hysteria. It is believed to work by increasing GABA levels in the brain, and since gamma aminobutyric acid is the primary inhibitory or sedating neurotransmitter, increasing GABA lowers the effects of noradrenaline, promotes relaxation, and sedates an over-stimulated mind and body.

Calming and Nervine Formulas

A Formula for Chronic Stress (warming)

• 2 parts rhodiola
• 1 part licorice
• 1 part cinnamon
• 1 part holy basil

A Formula for Chronic Stress (cooling)

• 2 parts eleuthero
• 1 part lemon balm
• 1 part motherwort
• 1 part licorice

A Formula for Excitatory Anxiety

• 2 parts ashwagandha
• 1 part motherwort
• 1 part passionflower or St. John’s wort
• 1 part chamomile

Depression, Post-Traumatic Stress Disorder, and Post-Partum Depression

Illnesses associated with mild, moderate, and severe depression include post-traumatic stress disorder (PTSD), post-partum depression (PPD), and, of course, depression, among others. These conditions vary widely in their cause (PTSD seems to be experience-related and also injury-related while PPD appears hormonally driven), though they share many of the same symptoms: fatigue, loss of will to act, confusion, sadness, bleakness, and in many cases a tendency toward violence against self or others.

Working in tandem with counselors and other healing arts professionals, consider the following herbs in a formula that includes antidepressants and nervine tonics and perhaps cardiotonics and digestive aids:

• lemon balm (Melissa officinalis): mildly sedative, lemon balm is carminative and spasmolytic as appreciated in digestion. It is also antiviral and is approved by the Commission E for nervousness and insomnia. 36 Lemon balm is ideal for conditions where sadness, grief, and depression interfere with clarity of thought.
• passionflower (Passiflora incarnata): the leaves, and to a lesser extent the flowers, contain alkaloids and other compounds that bind to the same areas of the brain influenced by GABA, acting to calm the nervous system; passionflower is anxiolytic and in some people is sedative. Contraindicated in pregnancy.
• rhodiola (Rhodiola rosea): this flavonoid-rich, Northern Hemisphere wildflower has a pronounced effect on the central nervous system. It is considered an adaptogen and anxiolytic and has been the subject of numerous clinical and laboratory studies. The root has demonstrated significant anti-fatigue and endurance effects, despite the plant’s lack of caffeine, and it is an effective herb to treat depression that is brought about by chronic fatigue, overwork, excessive physical activity, and overexertion. 37 It is contraindicated in people with bipolar disorder, especially those with a high-manic tendency.
• St. John’s wort (Hypericum perforatum): St. John’s Wort apparently works in part because of its “reuptake” effect on the monoamine neurotransmitter serotonin. Serotonin is primarily found in the gastrointestinal tract, where it helps manage gut muscle movements. But a small part of the human body’s serotonin is found in the central nervous system where it regulates mood, appetite, cognitive functions, such as memory and learning, and desire for or ability to sleep. (Serotonin also gets into the bloodstream and helps with the clotting factor of platelets.) St. John’s wort has been studied extensively as an antidepressant and shows activity as a GABA binder and MAOI. The herb apparently increases the liver’s ability to metabolize certain chemicals, making it contraindicated in clients already taking other MAOIs, anticoagulants, or other prescription medications. 38

Depression, Post-Traumatic Stress Disorder,
and Post-Partum Depression Formulas

A Formula for Mild, Occasional Depression

• 2 parts oats milky tops
• 1 part St. John’s wort
• 1 part lavender
• 1 part holy basil

A Formula for Mild, Chronic Depression

• 2 parts rhodiola
• 2 parts lemon balm
• 1 part peppermint
• 1 part passionflower

A Formula for Post-Traumatic Stress Disorder (PTSD)

• 2 parts linden
• 1 part motherwort
• 1 part eleuthero
• 1 part turmeric

A Formula for Post-Traumatic Stress Disorder (PTSD)

• 2 parts eleuthero
• 1 part motherwort
• 1 part St. John’s wort
• 1 part oats

A Formula for Post-Partum Depression (PPD)

• 2 parts motherwort
• 2 parts oats
• 1 part eleuthero
• 1 part yellow dock
• 1 part lemon balm

Another Formula for Post-Partum Depression (PPD)

• 2 parts holy basil (tulsi)
• 1 part lemon balm
• 1 part angelica
• 1 part black cohosh

A Formula for Mild Depression

• 2 parts St. John’s wort
• 2 parts lemon balm
• 2 parts oats milky tops
• 1 part eleuthero

A Formula for Mild Depression with No Desire to Eat

• 2 parts motherwort
• 1 part chamomile
• 1 part holy basil
• 1 part nettle

ADD/ADHD

The symptom complexes of attention deficit disorder (ADD) and attention deficit hyperactivity disorder (ADHD) are easy to spot but are of indeterminate origin. No one has been able to pinpoint one particular cause of ADD or ADHD, though genetics, environmental factors, diet, and neurological factors have all been implicated, and due to this complexity and the rampant diagnoses in the United States in recent years, a complete discussion of ADD/ADHD is beyond the scope of this book. However, many herbs used both traditionally and clinically are relevant for the healing arts practitioner interested in introducing herbs into a therapeutic practice.

Dr. Tieraona Low Dog mentions “disorder of the … dopamine systems” as a possible cause and suggests herbs such as lemon balm that affect the limbic-hippocampal area of the brain 39; other ideas suggest the disorders stem from brain circuit abnormalities. The hippocampus is tentatively identified as an organ responsible for helping people maintain both short-term and long-term memory, as it provides the “glue” that helps memories stick, and lemon balm directly affects it:

• lemon balm (Melissa officinale): helpful in cases of memory loss, mental clarity and ADD/ADHD, this fragrant herb affects the limbic-hippocampal area of the brain and its official uses are for nervousness and insomnia. It strengthens mental processes and is a favorite of test-takers and students, helping the hippocampus “sift” through what memories need glue and which ones don’t, allowing a child with ADD/ADHD to let go of excessive, irrelevant, or confusing stimuli. Lemon balm is antidepressant and is a prime tier 1 tonic for stress, tension or anxiety and a tier 2 specific for focus in ADD/ADHD.

ADD/ADHD Formulas

A Formula for ADD, for focus

• 2 parts lemon balm
• 1 part eleuthero
• 1 part ginkgo
• 1 part peppermint

A Formula for ADD/ADHD

• 2 parts lemon balm
• 1 part ashwagandha
• 1 part oats milky tops
• 1 part vervain

Collaborating with a client’s primary care providers, counselors, family, and other support team members is the best way to support his or her mental health in both acute and chronic conditions. Herbs can play a vital role in the improvement of these conditions and the nourishment of the brain and nervous system as a whole.

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29 Wheatley, David (2002).

30 Natarajan C., and John Bright (2002).

31 Jumbo-Lucioni, Patricia (2015).

32 Katzenschlager, Evans, and Manson (2004).

33 Thompson Healthcare Inc. (2007).

34 Ibid. 232.

35 Romm, Aviva (2010), 247.

36 American Botanical Council (1990).

37 Robertsdottir (2013), 296.

38 Romm (2010), 544.

39 Low Dog (1997).