It is a misnomer to say that our mind is our brain. It is not. Our minds are much bigger than our physical brains. Indeed, they are much larger than our nervous system. The discovery of mirror neurons has turned all of our thinking about what we knew of the mind and the soul on its head. If it hasn’t, you aren’t listening to the Spirit’s rumblings. Mirror neurons were discovered in primates in the 1980s and have been studied since then. It is only in the last ten to fifteen years however that inroads have occurred in psychological research.
Mirror neurons fire when we observe another’s person’s behavior or emotions. They reflect the other person’s experience to us as if the behavior was one’s own. They facilitate empathy and allow us to enter into the story of another. As I watch you feel or behave, I feel as if I am feeling or doing the same thing. As you feel, I feel with you. As you accomplish victory, I can feel it as if it were my victory. As you experience defeat, I feel a feeling of loss or disappointment. Now, it has to be noted that I do not feel in the same way that you feel. My memory, in concert with my mirror neurons, recognizes your feeling, determining my emotion. If I am watching you experience or act, my mirror neurons reflect your actions or experiences to my system, and I feel emotions as if I were you. Mirror neurons reside in the prefrontal cortex. When it is offline, mirror neurons are also offline, and empathy is no longer possible. This directly impacts our ability to love and move toward one another. If we are defensive, our amygdala is in control of our limbic brain we are not free to love.
Before we go any further, we have to talk about some chemicals that affect our brain and even function as a switch to give control to either the amygdala or the pre-frontal cortex. Once again, we are only scratching the surface of brain chemistry. Let me introduce you to three important chemicals that play important roles in our ability to love: Cortisol — the chemical that surrounds the amygdala determining how on edge we are; dopamine — the chemical that determines our peacefulness; and, oxytocin – the chemical that helps us feel connected to another human being. Though all of these chemicals impact the mind’s function, none of them are exclusively triggered or regulated by the brain. The Vagus Nerve plays a role in how they are produced and controlled.
The Vagus Nerve runs from the brain stem (which handles all your automatic body functions such as heart rate, body heating and cooling, hiccups and yawns, and elimination system functions) through the back of the throat through the pulmonary and cardiovascular centers and down into the intestines. It is the reason that our throats get dry, or our stomach is tied up in knots. It is the reason our heart races, we catch our breath, can’t speak, and have digestive issues. It also affects how much cortisol, dopamine, and oxytocin is created and sent to the brain to regulate or stimulate emotion.
The Vagus Nerve is not a one-directional, body-to-brain- freeway. It carries information both ways. Trauma and shame travel down the Vagus Nerve, from the brain into the body lodging there. Because of this, our bodies “remember” better than our brains. As Dr. Dan Allender says in nearly every class he teaches, “All memory is a myth.” 1 While our right, limbic brains store images, smells, sounds and feelings arising from those events, the narrative our mind holds is strictly a memory of our last thought of the event, rather than the event itself. It is our bodies that store the feelings that arise from or are inflicted directly from the experience. Because of this, our bodies hold our best memory of it, even if we cannot remember any of the narratives.
Because of this, if we hope to love people who are victims of trauma, or who are suffering from chronic shame, merely helping our clients change their thoughts will have little impact. If we are limited or focus on this modality, our attempts to love our clients well may cause harm. This is also why Evidenced Based Theories (CBT, ACT, and DBT, etc.) that are very helpful in addressing problem behaviors and addictions, as well as creating psychic space for work deeper work to be done, can retraumatize someone who is suffering from either early, chronic PTSD or chronic shame. Their thoughts are not the problem their non-verbal memory that is stored in the right limbic brain, brainstem, and the body is. To love these people well, we have to rethink how we work.
Trauma, Health, and the Vagus Nerve
When working with clients with chronic trauma I commonly hear stories of seizures, migraines, gastrointestinal problems, and autoimmune disorders. The connection between trauma and health is complex, not surprising because there is still so much to learn about our bodies. One component that has been in the news recently is the vagus nerve, an extensive nerve that is taking center stage as a potential “off switch” for disease.
I find this of interest because one’s mental health can have a significant influence on the vagus nerve. So it is no surprise that vagus nerve regulation can be important for responding effectively to the emotional and physiological symptoms of depression, anxiety, and PTSD.
“Do you have a sensitive nervous system that adversely impacts your health? By developing an understanding of the workings of your vagus nerve you may find it possible to work with your nervous system rather than feel trapped when it works against you. Fine tune your self-care with vagus nerve regulation strategies that can be practiced in the comfort of your home.“
-Dr. Arielle Schwartz
Get to Know Your Vagus Nerve
The vagus (Latin for wandering) nerve is far reaching, extending from the brainstem down into your stomach and intestines, enervating your heart and lungs, and connecting your throat and facial muscles. Furthermore, Stephen Porges’ polyvagal theory proposes that there are three evolutionary stages of the vagus nerve and that regulation of nervous system states is critical for the treatment of mental health conditions (you can read here in my blog about polyvagal theory).
Did you know that nerve fibers existing throughout your stomach and intestines are referred to as your enteric brain? That is because 90% of those nerve fibers connect back up to the brain through the vagus nerve. A key player in the body-mind connection, the vagus nerve is behind your gut instinct, the knot in your throat, and the sparkle in your smile. You can think of the vagus nerve as a two-way radio communication system helping you stay in touch with your sensations and emotions. What happens in vagus definitely doesn’t stay in vagus.
Vagus Nerve in the News
Several recent articles have discussed medical interventions that provide a potential cure for many physical and mental health conditions (wired.com; businessinsider.com,huffingtonpost.com). The vagus nerve is taking center stage as a potential “off switch” for inflammation related diseases such as epilepsy, rheumatoid arthritis, and inflammatory bowel syndrome. Regulation of the vagus nerve also plays a significant role in mental health care allowing you to effectively respond to the emotional and physiological symptoms of depression, anxiety, and PTSD.
The field of bio-electronic medicine offers Vagus Nerve Stimulation (VNS) as an intervention to treat rheumatoid arthritis, epilepsy and depression by surgically implanting tiny electronic devices that can send shocks to the vagus nerve. Further research is looking at noninvasive external devices, not yet approved by the FDA, that provides vagus nerve stimulation through the skin. The long term implications of these “electroceuticals” may provide promise for those suffering from chronic disease, depression, and PTSD.
Vagus Nerve Stimulation and Inflammation
The vagus nerve is essential for keeping your immune system in-check. There is a close connection between chronic stress, immune functioning, and inflammation. In brief, short-term activation of your sympathetic nervous system releases of cortisols and helps keep your immune system at healthy levels. Long-term stress suppresses immunity. However, chronic traumatic stress has an inverse reaction, leaving your immune system unchecked which leads to inflammation in the body (you can read more here in my blog on chronic stress and disease).
Activation of the vagus nerve keeps your immune system in check and releases an assortment of hormones and enzymes such as acetylcholine and oxytocin. This results in reductions in inflammation, improvements in memory, and feelings of relaxation. Vagus nerve stimulation has also been shown to reduce allergic reactions and tension headaches.
The Goldilocks Principle
Regulation of the nervous system relies upon the goldilocks principle. We recognize we are “too hot” when we feel keyed up, anxious, irritable, or panicky. We are too “too cold” when we are shut down, depressed, or feeling hopeless. Sometimes we alternate between the two which is like driving with one foot on the gas and one on the brakes. Practices that regulate the vagus nerve are aimed towards either relaxing or re-energizing ourselves depending upon what is needed to feel “just right.”
5 Vagus Nerve Stimulation Exercises
Unless you have a surgically implanted device you actually cannot directly stimulate your vagus nerve; however, you can indirectly stimulate your vagus nerve to relieve keyed up or shut down nervous system states. Remember, your vagus nerve passes through your belly, diaphragm, lungs, throat, inner ear, and facial muscles. Therefore, practices that change or control the actions of these areas of the body can influence the functioning of the vagus nerve through the mind-body feedback loop. You can try these from the comfort of your living room:
- Humming: The vagus nerve passes through by the vocal cords and the inner ear and the vibrations of humming is a free and easy way to influence your nervous system states. Simply pick your favorite tune and you’re ready to go. Or if yoga fits your lifestyle you can “OM” your way to wellbeing. Notice and enjoy the sensations in your chest, throat, and head.
- Conscious Breathing: The breath is one of the fastest ways to influence our nervous system states. The aim is to move the belly and diaphragm with the breath and to slow down your breathing. Vagus nerve stimulation occurs when the breath is slowed from our typical 10-14 breaths per minute to 5-7 breaths per minute. You can achieve this by counting the inhalation to 5, hold briefly, and exhale to a count of 10. You can further stimulate the vagus nerve by creating a slight constriction at the back of the throat and creating an “hhh”. Breathe like you are trying to fog a mirror to create the feeling in the throat but inhale and exhale out of the nose sound (in yoga this is called Ujjayi pranayam).
- Valsalva Maneuver: This complicated name refers to a process of attempting to exhale against a closed airway. You can do this by keeping your mouth closed and pinching your nose while trying to breathe out. This increases the pressure inside of your chest cavity increasing vagal tone.
- Diving Reflex: Considered a first rate vagus nerve stimulation technique, splashing cold water on your face from your lips to your scalp line stimulates the diving reflex. You can also achieve the nervous system cooling effects by placing ice cubes in a ziplock and holding the ice against your face and a brief hold of your breath. The diving reflex slows your heart rate, increases blood flow to your brain, reduces anger and relaxes your body. An additional technique that stimulates the diving reflex is to submerge your tongue in liquid. Drink and hold lukewarm water in your mouth sensing the water with your tongue.
- Connection: Reach out for relationship. Healthy connections to others, whether this occurs in person, over the phone, or even via texts or social media in our modern world, can initiate regulation of our body and mind. Relationships can evoke the spirit of playfulness and creativity or can relax us into a trusting bond into another. Perhaps you engage in a lighthearted texting exchange with a friend. If you are in proximity with another you can try relationship expert, David Snarch’s simple, yet powerful exercise called “hugging until relaxed.” The instructions are to simply “stand on your own two feet, place your arms around your partner, focus on yourself, and to quiet yourself down, way down.”
Knowing practices for self-care are important. However, it is also important to know how and when to seek out professional therapeutic help. Asking for help can often be the hardest step. You do not need to walk the healing path alone.
Vagus Nerve and the Gut of Gut Reactions
The vagus nerve is your body’s master reset button. Vagus means wandering in Latin, so the nerve was called the “wandering” nerve for the circuitous path it takes from the brain to all the organs in the chest and abdomen. The vagus nerve influences heart rate, respiration, and digestion, but it’s also the brain’s way of monitoring what is going on with those organs. The vagus nerve is your CEO of calm. It’s the commander-in-chief of your parasympathetic nervous system. The vagus nerve has the important job of ending your body’s fight-or-flight response once a stress has passed. That is why vagus nerve stimulation is effective for mood, and has been approved as a treatment for depression. The Vagus Nerve arises from the medulla in the brain and passes through the skull down within the chest cavity where it branches off in multiple directions to innervate organs and muscles. 80 to 90 percent of the nerve fibers are devoted to sending information from the organs/gut back to the brain. The Vagus nerve is responsible for speech, swallowing, keeping the larynx open for breathing, slowing heart rate, monitoring and initiating digestive processes, and modulating inflammation, among other actions. The Vagus nerve is the main line of communication between the brain and the energy-producing digestive tract. It also relays information to the brain from what is known as the Enteric Nervous System (ENS) our “second brain” controlling the digestive process; it is made up of over 500 million neurons that surround the digestive tract. Vagus nerve stimulation can also relieve migraines and quench inflammation. Most of the traffic in the vagus (80% of its messages) travel upstream from the body to the brain. That’s why the vagus is so important for mood. It monitors the organs to determine if all is well, and when it is, then the mind can rest easy. Contented.
What will resetting our Vagus Nerve do for us? If properly stimulated it can: Turn on neurogenesis, helping our brains sprout new brain cells. Rapidly turn off stress, hyper-arousal, and fight/flight via the relaxation response. Sharpen our memories. Fight inflammatory disease. Help us resist high blood pressure. Block cortisol and other oxidizing agents that age and deteriorate us. Block body-wide inflammation the major agent of aging and poor health. Help us overcome depression and anxious overwhelm. Help us sleep better.Raise levels of human growth hormone. Help us overcome insulin resistance. Turn down allergic responses. Lower chances of getting stress and tension headaches. Help spare and grow our mitochondria a key to our energy levels. Affect our overall ability to live longer, healthier, and more energetic lives. Wow!
How to Activate the Vagus Nerve? This nerve can become underdeveloped/deactivated if the body’s in a constant state of fight-or-flight due to the stress and anxiety that comes with living in today’s society. This keeps the sympathetic nervous system in survival overdrive: your breathing becomes rapid and shallow, your heart rate increases and digestion becomes impaired. Vagus nerve stimulation can be turned on by breathing and relaxation exercises… deep/slow belly breathing, holding your breath, cold water immersion, chanting…..
To practice deep breathing, inhale through your nose and exhale through your mouth. Breathe more slowly.Breathe more deeply, from the belly. Exhale longer than you inhale. https://sites.google.com/site/stanleyguansite/health/health-tips/breathe-deeply-to-activate-vagus-nerve
The acts of chanting, both listening and vocalizing, stimulate the vagus nerve through muscle movements in the mouth, like those important to speech and those that work the larynx for breathing. The nerve also connects to vocal chords and receives some sensation from the outer ear; thus the acts of vocalizing and listening can influence it. Another amazing fact about the vagus nerve is its connection to the seven chakras; these ganglions of nerves branch out to all of the seven centers of your body. So working with our bodies chakra system by aligning and getting them spinning in the correct direction will also reset our Vagus Nerve.
How does mercury affect human animals and why is this important now? Amalgam dental fillings and vaccinations containing mercury specifically affect humans disrupting many metabolic functions leading to sickness. Ingested mercury blocks the action of several key enzymes in humans and other animals.” Ocean level mercury has tripled so much of the fish we are eating is full of mercury. Once in the human body, mercury acts as a neurotoxin, interfering with the brain and nervous system. Continued exposure leads to the accumulation of mercury in the body.Exposure to mercury can be particularly hazardous for pregnant women and small children. Even in low doses, mercury may affect a child’s development, delaying walking and talking, shortening attention span and causing learning disabilities. Less frequent, high dose prenatal and infant exposures to mercury can cause mental retardation, cerebral palsy, deafness and blindness.
The importance of resetting the Vagus Nerve came through a shamanic telestic session. A key piece of intel for the human species at this time! “The vagus nerve in humans is not directly involved in the management of body temperature. It operates more as an electrical switchboard, relaying information between the two branches of the autonomic nervous system, the enteric nervous system the organs and the brain. Its main function in the body is to maintain energy balance, ie normal metabolism by switching connections between the organs and the brain through a system of neurotransmitters and enzymes. It has been called ‘the mirror of the central nervous system.’ (It is also involved in the production of oxytocin, through the activation of mirror neurons.) The mirroring attention is multi-faceted. Now that the Aeon Sophia is lucid in Her Dreaming, the mirroring function of the vagus system is activated at the level of the Gaia-Sapiens exchange, but She is not receiving sufficient data on human metabolic activity at a species level in order to maintain an optimum and stable temperature in the environment….. Some of the ways given in the tesletic session for resetting the Vagus Nerve were yawning, belly laughs, shouting, stretching back to look at the sky and immersing our heads in a bucket of freezing water, laying on the ground and looking at the stars (physical connection with the earth enables us to manage our own body temperatures efficiently.)
Secrets of the Vagus Nerve
July 2012 | TRT 6:17
Dacher Keltner shares his research on the vagus nerve, a key nexus of mind and body and a biological building block of human compassion.
In science, this hormone is referred to as the official neuropeptide of “attachment.” This article brings you up to snuff (the bulk of research on oxytocin is on the intranasal delivery mode) on the clinical applications of oxytocin replacement. You will learn that it is a team player with our sex steroid hormones, our ability to be lean and not mean, and as part of the Buddha (vagal) pathway between the brain and gut.9
Oxytocin is a peptide hormone. Peptide hormones are made of amino acids. A peptide is a link of two or more amino acids. As far as peptide hormones go, oxytocin is a small thing, with only nine amino acids. In comparison, thyroid-stimulating hormone (TSH) contains 201. Sometimes oxytocin is referred to as a nonapeptide, since nona means “nine.”
Oxytocin is historically appreciated for its role in pregnancy. It signals uterine contractions, lets down milk for lactation, and deepens bonding between mother and child.10,11 But there’s more. Emergent research and clinical evidence reveal ever-expanding possibilities for oxytocin replacement in the clinical trenches. For example, oxytocin therapy is being used to treat autism spectrum disorder, schizophrenia, obesity, addiction, erectile dysfunction, and orgasm disorders, and as a libido, orgasm, and emotional “bonding” enhancer.12-14
Viagra has become a household word. It’s an effective, best-selling sexual medication. Viagra has also been looked at for treating depression and other mental disorders.15,16 Why? It boosts oxytocin production.17
Hormones are signaling molecules, or “e-mailers” in the body’s physiologic Internet system. Hormones are made in various organs throughout the body. For example, oxytocin is made in the brain. These hormones are then secreted into the watery highways of the blood, where they swim to specific tissues in search of perfectly fitting receptors. Receptors are proteins shaped like malleable satellite dishes. Hormones swim into their exact receptor. Once inside, the hormone docks into specific binding domains. Marching orders are delivered to genes. Based on these directives, cells take action.
Much of the cross-talk communication that takes place to nudge life to unfold is due to hormonal (ligand to receptor) and genomic (delivering to genes) signaling. There are other forms of signaling, such as receptor-free and nongenomic signaling, but they are beyond the scope of this article.
Oxytocin (OT) delivers messages to specific oxytocin receptors (OTR). We have oxytocin receptors globally in our human biologic real estate, not just in reproductive tissues. I have been using oxytocin replacement in practice for 5 years and have some startling case histories as well as some duds. Five summaries are presented later in this article.
Oxytocin is produced in the hypothalamus.18 It is made by the neurons of the paraventricular and supraoptic nuclei of the hypothalamus (the same areas of the brain turned on by orgasm; the bigger the orgasm, the more these cells are “turned on”).19,20 These hypothalamic neurons have axons that deliver OT both locally and peripherally.
The brain has high levels of OTRs to receive a wide array of signals. Oxytocin acts as a neurotransmitter signaling the amygdala (seat of faith vs. fear), the nucleus accumbens (sense of well-being), and the hippocampus (home of short-term memory and confidence).21 Oxytocin traverses cerebral regions by diffusing across neural tissue, like you would cut across lanes to get to an off-ramp on a freeway.22 There are OTR receptors throughout the entire spinal cord.23
Animal model research emphasizes a strong relationship between the expression of OT in the brain and the ability to have socially monogamous attachment behavior. These investigations began with the vole. It’s amazing research.
Two closely related species of voles have exact opposite relationship styles: one is monogamous, mating for life, while the other is promiscuous, choosing to be a forever player. What’s the biological difference? The monogamous prairie vole has many more oxytocin and vasopressin (a playmate with oxytocin) receptors and activity in the brain. In comparison, the polygamous vole has far fewer such bonding receptors, and thus, more sleuthing mating behaviors.
Researchers have gone to the trouble of reversing these mating behaviors. They accomplished this by reengineering Mother Nature. By altering OT genes, they could morph typically promiscuous male voles into becoming devoted monogamous voles, and mate-for-life type voles into tomcat types. How? They altered the numbers of oxytocin genes. By reducing or increasing oxytocin signals (and its cohort, vasopressin) in the brain, they could reproducibly alter biologic desire for either monogamy or bigamy (though some say this should be dubbed “pig-amy”).24,25
Moving forward from these findings, Young and Wang manipulated three attachment hormone musketeers (oxytocin, vasopressin, and dopamine) and influenced preference of one beloved over another. They “gene-jury-rigged” whom the animals would choose to mate with. They named this the neurobiological model of pair bonding.26 A number of researchers have pleaded the case that this is how humans basically meet, mingle, and mate, too.27,28
We know that moms and babes bond through oxytocin. Magnetic imaging of the brains of mothers who see photos of their own infants (compared with pics of matched control infants unknown to them) show that the areas of the brain that “activate” are flush with oxytocin, vasopressin, and dopamine receptors.29
It’s clear. Oxytocin deserves to be called “the cuddle hormone,” “the love hormone,” or “the cuddle chemical.”
Oxytocin helps buffer stress. It has hormonal influence over the hypothalamus/pituitary/adrenal axis (HPA axis). At various levels OT helps the host cope with stress and promotes anti-anxious reactions.30 In other words, OT signaling reduces the font size of suffering caused by stress.
Sex Hormones and Oxytocin
Sex steroid hormones – estrogen, testosterone, and progesterone – intimately interact with OTR and are part of sex hormonal influence over human emotions. Estrogens act synergistically with OT by enhancing its anxiolytic effects and increasing OTR levels. A single dose of estradiol increases plasma OT levels in women (one of the many reasons that estrogen replacement makes many women enjoy happier moods and avoid antidepressants) and a metabolite of testosterone (nicknamed 3beta-diol) has similar input in the brain and other critical areas, such as within the HPA axis.
Estrogen Receptor β
Estrogen has two major receptors that receive estrogen signals: ER alpha and ER beta. ER beta is an oncogene suppressor (protects against cancer) and anti-inflammatory molecule balancing out the pro-growth signals of ER alpha. Areas in the brain with OTRs stunningly overlap with exactly where ER beta-receptors live.32
Activation of ER beta normalizes HPA axis activity and acts to buffer stress and anxiety. Approximately 85% of OT neurons in the pituitary coexpress ER beta! There is grand crosstalk between OT and ER beta throughout the body. The multiple interplays are just now being explored. I prophesy that the “good” and “bad” roles of oxytocin and estrogen receptor beta will takes twists and turns because in some cellular places (such as the breast, prostate and brain), ER beta dominance (having many of these receptors) is what we want for tissue protection, but in other conditions (such as endometriotic implants and dysfunctional endothelium) this is not the case.
There also appears to be a “threesome” between a metabolite of testosterone (3B-diol – itself a promoter of ER beta) and ER beta and OT. All three synergize, especially in the brain and the vagus nerve.
Vagal or Buddhist Nerve Highway
In utero, when the fetus is developing, a mass of cells that are to become our brain and gut divide in half, and one cellular clump travels northerly to the brain and the other southerly to the gut. What connects the two throughout life is the vagus nerve. It’s the second largest nerve system after the spinal cord. It’s the longest cranial nerve, extending from the brain to the gut and other crucial organs. It starts in the brainstem behind the ears, travels down each side of the neck, across the chest, and throughout the abdomen. It connects the brain to the stomach and digestive tract and many other organs such as the lungs and the heart.
The vagus nerve is a bundle of multiple thousands of nerve fibers, of which 80% are sensory, meaning that these nerves report and reinforce back to the brain what’s going on in the gut and the rest of the body. It’s cellular Big Brother. The vagus nerve is a crucial part of the parasympathetic nervous system (though some is sympathetic, too). It is mostly the opposite of flight and fight.
Healthy vagal tone creates calm. Everyone has their own vagal footprint. The better the vagal tone, the less ruffled we are by stress and the more cast-iron stomachs we seem to enjoy. A healthy digestive tract is mostly parasympathetically “vagal.”
The healthier your vagal tone, the lower your level of cellular inflammation, or the faster you bring inflamed tissues back to normal after infection, or the more peaceful your moods or the faster recovery back to calm after an emotional storm has hit.33
Oxytocin appears to be a major hormone player traveling vagal highways, maintaining calm, hormonal satiety and peace, suppressing inflammation, and more.34 Being a hormone of connectivity, oxytocin upregulation in the vagal nerve – this massive internal feedback loop – may be part of feeling well and right with the world. Meditation boosts vagal tone and oxytocin.35
Again, crosstalk abounds. The vagus nerve is not only flush with oxytocin receptors, this large feedback nerve also influences the number of estrogen receptors in the nervous system and brain.36 Remarkable!
Adults shown photos of a romantic partner with whom they are “intensely in love” light up brain areas flush with oxytocin, vasopressin, and dopamine receptors.37
A number of studies have looked at mating under experimental conditions, before and after orgasm, and when giving couples nasal administration of oxytocin, which delivers it directly to the brain. These have been done in both observational manners (not randomized controlled) and in double-blind, placebo-controlled scientific experimental design. These studies are where the hormonal rubber meets the enhancement effectiveness road.
Oxytocin replacement has been shown to create more pleasurable orgasms and a stronger sense of empathy in both men and women. Men given OT intranasally report the biggest bang, perhaps since during orgasm they naturally make less oxytocin than women, so any bump up might be more noticed.
Since men produce less oxytocin, a bonding hormone, they are less vulnerable to intimacy attachment compared with women.38,39 The highest experimental recorded levels of oxytocin, by the way, were shown to be achieved in women who were multiorgasmic.40 The more oxytocin, the more orgasms – if a woman is capable of having these types of releases. (My theory is that all women are capable, but not all are hormonally replete, or in shape emotionally or physically, or they or their partners have simply not been taught how. I have a new book coming out that outlines exact details.)
Acedemia Posts (Mirror Neurons)
Mirror neurons are one of the most important discoveries in the last decade of neuroscience. These are a variety of visuospatial neurons which indicate fundamentally about human social interaction. Essentially, mirror neurons respond to actions that we observe in others. The interesting part is that mirror neurons fire in the same way when we actually recreate that action ourselves. Apart from imitation, they are responsible for myriad of other sophisticated human behavior and thought processes. Defects in the mirror neuron system are being linked to disorders like autism. This review is a brief introduction to the neurons that shaped our civilization.
Mirror neurons represent a distinctive class of neurons that discharge both when an individual executes a motor act and when he observes another individual performing the same or a similar motor act. These neurons were first discovered in monkey’s brain. In humans, brain activity consistent with that of mirror neurons has been found in the premotor cortex, the supplementary motor area, the primary somatosensory cortex, and the inferior parietal cortex [Figure 1].
Originally discovered in a subdivision of the monkey’s premotor cortex, area F5, mirror neurons have later been also found in the inferior parietal lobule (IPL). IPL receives a strong input from the cortex of the superior temporal sulcus (STS), a region known to code biological motion, and sends output to ventral premotor cortex including area F5.
Neurophysiological (EEG, MEG, and TMS), and brain-imaging (PET and fMRI) experiments provided strong evidence that a fronto-parietal circuit with properties similar to the monkey’s mirror neuron system is also present in humans. As in the monkey, the mirror neuron system is constituted of IPL and a frontal lobe sector formed by the ventral premotor cortex plus the posterior part of the inferior frontal gyrus (IFG).
Human infant data using eye-tracking measures suggest that the mirror neuron system develops before 12 months of age, and that this system may help human infants understand other people’s actions. Two closely related models postulate that mirror neurons are trained through Hebbian or associative learning.[4,5]
THE HEBBIAN THEORY
Donald Hebb in 1949 postulated that a basic mechanism for synaptic plasticity wherein an increase in synaptic efficacy arises from the presynaptic cell’s repeated and persistent stimulation of the postsynaptic cell. When an axon of cell A is near enough to excite a cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A’s efficiency, as one of the cells firing B, is increased. The theory is often summarized as “Cells that fire together, wire together.” This Hebbian theory attempts to explain “associative learning”, in which simultaneous activation of cells leads to pronounced increases in synaptic strength between those cells. Such learning is known as Hebbian learning.
In 1990s, a group of neurophysiologists placed electrodes in the ventral premotor cortex of the macaque monkey to study neurons specialized for the control of hand and mouth actions. They recorded electrical signals from a group of neurons in the monkey’s brain while the monkey was allowed to reach for pieces of food, so the researchers could measure their response to certain movements. They found that some of the neurons they recorded from would respond when the monkey saw a person pick up a piece of food as well as when the monkey picked up the food.
In another experiment, they showed the role of the mirror neuron system in action recognition, and proposed that the human Broca’s region was the homologue region of the monkey ventral premotor cortex. Subsequently, a study by Ferrari Pier Francesco and colleagues described the presence of mirror neurons responding to mouth actions and facial gestures.
A recent experiment by Christian Keysers and colleagues have shown that, in both humans and monkeys, the mirror system also responds to the sound of actions. Functional magnetic resonance imaging (fMRI) can examine the entire brain at once and suggests that a much wider network of brain areas shows mirror properties in humans than previously thought. These additional areas include the somatosensory cortex and are thought to make the observer feel what it feels like to move in the observed way. Neuropsychological studies looking at lesion areas that cause action knowledge, pantomime interpretation, and biological motion perception deficits have pointed to a causal link between the integrity of the IFG and these behaviors.[10,11] Transcranial magnetic stimulation studies have confirmed this as well.
Mukamel et al. recorded activity from 1177 brain neurons of 21 patients suffering from intractable epilepsy. The patients had been implanted with intracranial depth electrodes to identify seizure foci for potential surgical treatment. Electrode location was based solely on clinical criteria; the researchers, used the same electrodes to “piggyback” their research. The experiment included three phases; making the patients observe facial expressions (observation phase), grasping (activity phase), and a control experiment (control phase). In the observation phase, the patients observed various actions presented on a laptop computer. In the activity phase, the subjects were asked to perform an action based on a visually presented word. In the control task, the same words were presented, and the patients were instructed not to execute the action. The researchers found a small number of neurons that fired or showed their greatest activity both when the individual performed a task and when they observed a task. Other neurons had anti-mirror properties, that is, they responded when the participant saw an action but were inhibited when the participant performed that action. The mirror neurons found were located in the supplementary motor area and medial temporal cortex.
POSTULATED FUNCTIONS OF MIRROR NEURONS IN HUMANS
Mirror neurons are associated with one of the most intriguing aspect of our complex thought process, that is “Intention understanding”. There are two distinct processes of information that one can get observing an action done by another individual. The first component is WHAT action is being done? And the second more complex component is WHAT FOR or, WHY (Intention) the action is being done. Figure 2 is a representation of the consequences described. The complex beauty of the discussed subject is the second component where our mirror neurons premonate the future action which is yet to occur. Two neuroscientists first hypothesized that mirror neurons are involved in intention understanding, which was later supported by fMRI study. In this experiment, volunteers were presented with hand actions without a context and hand actions executed in contexts that allowed them to understand the intention of the action agent. The study demonstrated that actions embedded in contexts yielded selective activation of the mirror neuron system. This indicates that mirror areas, in addition to action understanding, also mediate the understanding of others’ intention. These data indicate that the mirror neuron system is involved in intention understanding, though, it fails to explain the specific mechanisms underlying it.
In order to explain this hypothesis, a study was carried out on two rhesus macaque monkeys [Figure 3]. The monkeys were trained to perform two actions with different goals. The schematic representation is shown in Figure 2.
In the first, the monkey had to grasp an object in order to place it in a container. In the second, it had to grasp a piece of food to eat it. The initial motor acts, reaching and grasping, were identical in the two situations, but the final goal oriented action was different. The activity of neurons was recorded from the IPL, which has long been recognized as an association cortex that integrates sensory information. The results showed that 41 mirror neurons fired selectively when the monkey executed a given motor act (e.g. grasping). However interestingly, only specific sets (15 neurons) within the IPL fired during the second goal constrained acts.
Some of these “action-constrained” motor neurons had mirror properties and selectively discharged during the observation of motor acts when these were embedded in a given action (e.g., grasping-for-eating, but not grasping-for-placing). Thus, the activation of IPL action-constrained mirror neurons give information not only about, but also on why grasping is done (grasping-for-eating or grasping-for placing). This specificity allowed the observer not only to recognize the observed motor act, but also to code what will be the next motor act of the not-yet-observed action, in other words to understand the intentions of the action’s agent.
Autism and intention understanding
It has been postulated and proved by neuroscientists that the inability of autistic children to relate to people and life situations in the ordinary way depends on a lack of a normally functioning mirror neuron system.[17–19] EEG recordings mu waves from motor areas are suppressed when someone watches another person’s move, a signal that may relate to the mirror neuron system. This suppression was less in children with autism.
Basically autism is characterized by two neuropsychiatric abnormalities. First is the defect in the social-cognitive domain which presents as mental aloneness, a lack of contact with the external world and lack of empathy. The second is sensorimotor defects like temper tantrums, head banging, and some form of repetitive rituals. All these are now suggested to be because of some anomaly of the mirror neuron development. One interesting phenomena in autism is the inability to comprehend abstract reasoning and metaphors, which in normal humans is subserved by left supramarginal gyrus rich in mirror neurons. Mirror neuron abnormalities have also been blamed for a number of other autistic problems like language difficulties, self-identification, lack of imitation, and finally intention understanding.
However, the autistic enigma continues as whether the primary deficit in intention understanding found in autistic children is due to damage of the mirror neuron system as it is responsible for understanding the actions of others, or rather there exists more basic defects in the organization of the motor chains. In other words, the fundamental deficit in autistic children resides in the incapacity to organize their own intentional motor behavior.
Emotions and empathy
Many studies have independently argued that the mirror neuron system is involved in emotions and empathy.[20–23] Studies have shown that people who are more empathic according to self-report questionnaires have stronger activations both in the mirror system for hand actions and the mirror system for emotions, providing more direct support for the idea that the mirror system is linked to empathy. Functions mediated by mirror neurons depend on the anatomy and physiological properties of the circuit in which these neurons are located. Emotional and empathetic activations were found in parieto-premotor circuits responsible for motor action control. In a fMRI experiment represented schematically below, [Figure 4] one group of participants were exposed to disgusting odorants and, the other group, to short movie clips showing individuals displaying a facial expression of disgust. It was found that the exposure to disgusting odorants specifically activates the anterior insula and the anterior cingulate. Most interestingly, the observation of the facial expression of disgust activated the same sector of the anterior insula. In agreement with these findings, the data are obtained in another fMRI experiment that showed activation of the anterior insula during the observation and imitation of facial expressions of basic emotions.
Similar results[26,27] have been obtained for felt pain and during the observation of a painful situation, which was involved another person loved by the observer. Taken together, these experiments suggest that feeling emotions is due to the activation of circuits that mediate the corresponding emotional responses.
Evolution of language and mirror neurons
The discovery of mirror neurons provided strong support for the gestural theory of speech etymology. Mirror neurons create a direct link between the sender of a message and its receiver. Thanks to the mirror mechanism, actions done by one individual become messages that are understood by an observer without any cognitive mediation. The observation of an individual grasping an apple is immediately understood because it evokes the same motor representation in the parieto-frontal mirror system of the observer. On the basis of this fundamental property of mirror neurons and the fact that the observation of actions like hand grasping activates the caudal part of IFG (Broca’s area), neuroscientists proposed that the mirror mechanism is the basic mechanism from which language evolved.
Humans mostly communicate by sounds. Sound-based languages, however, do not represent the only natural way for communication. Languages based on gestures (signed languages) represent another form of complex, fully-structured communication system. This hypothesis argues that speech is the only natural human communication system, the evolutionary precursor of which is from animal calls. The argument goes as follows: Humans emit sound to communicate, animals emit sounds to communicate, therefore human speech evolved from animal calls.
The contradictions of the above syllogism are:
The anatomical structures underlying primate calls and human speech are different. Primate calls are mostly mediated by the cingulate cortex and by deep, diencephalic, and brain stem structures. In contrast, the circuits underlying human speech are formed by areas located around the Sylvian fissure, including the posterior part of IFG.
Animal calls are always linked to emotional behavior contrary to human speech.
Speech is mostly a dyadic, person-to-person communication system. In contrast, animal calls are typically emitted without a well-identified receiver.
Human speech is endowed with combinatorial properties that are absent in animal communication.
Humans do possess a “call” communication system like that of non-human primates and its anatomical location is similar. This system mediates the utterances that humans emit when in particular emotional states (cries, yelling, etc.). These utterances are preserved in patients with global aphasia.
THEORIES OF LANGUAGE EVOLUTION AND ROLE OF MIRROR NEURON SYSTEM
The alternate hypothesis
According to this theory, the initial communicative system in primate precursors of modern humans was based on simple, elementary gesturing. Sounds were then associated with the gestures and became progressively the dominant way of communication. In fact, the mirror mechanism solved, at an initial stage of language evolution, two fundamental communication problems: Parity and direct comprehension. Thanks to the mirror neurons, what counted for the sender of the message also counted for the receiver. No arbitrary symbols were required. The comprehension was inherent in the neural organization of the two individuals.
It is obvious that the mirror mechanism does not explain by itself the enormous complexity of speech. but, it solves one of the fundamental difficulties for understanding language evolution, that is, how and what is valid for the sender of a message become valid also for the receiver. Hypotheses and speculations on the various steps that have led from the monkey mirror system to language have been recently advanced.
In humans, functional MRI studies have reported finding areas homologous to the monkey mirror neuron system in the inferior frontal cortex, close to Broca’s area, one of the hypothesized language regions of the brain. This has led to suggestions that human language evolved from a gesture performance/understanding system implemented in mirror neurons. Mirror neurons have been said to have the potential to provide a mechanism for action-understanding, imitation-learning, and the simulation of other people’s behavior. It must be noticed that the mirror neuron system seems to be inherently inadequate to play any role in the syntax, given that this definitory property of human languages which is implemented in hierarchical recursive structure is flattened into linear sequences of phonemes making the recursive structure not accessible to sensory detection.
Theory of cross-modal abstraction
The ability to make consistent connections across different senses may have initially evolved in lower primates, but it went on developing in a more sophisticated manner in humans through remapping of mirror neurons which then became co-opted for other kinds of abstraction that humans excel in, like reasoning metaphors. Development of sophisticated modules inside the brain makes us unique as far as language is concerned.
Examples: The connections between the inferior temporal gyrus (fusiform gyrus/visual processing area) and the auditory area guide sound mediated visual abstraction/synesthesia.
V. S. Ramachandran, a cognitive neuroscientist, demonstrates this through his famous bouba-kiki effect through cross-modal abstraction [Figure 5]. In this experiment, if we are to name the following diagrams with two given options (bouba and kiki) then, our brain predominantly names Figure 1 as bouba, and Figure 2 as kiki.
Analysis of bouba is abstracted in the visual center as somewhat gross, voluptuous, rounded, etc., and kiki is abstracted as somewhat sharp or more chiseled.
Example 2: Similarly doing “pincer-like” hand gestures while pronunciation of terms like “tiny”, “little”, “diminutive”, and pouting the lips outwards while pronunciation of words like “you” meaning pointing towards someone.
These features signify cross-modal connections of neurons between face and hand area in the motor cortex (motor-to-motor synkinesia).
This theory also revolves around mirror neurons. Onomatopoeia show how man perceives sound. Sounds are defined as disturbances of mechanical energy that propagates through matter as a wave. What makes a particular sound distinct from others are its properties like frequency, wavelength, period, amplitude, and speed. Onomatopoeia is an attempt to produce the sound we hear by converting it into symbols. For instance, we would say the sound a gun makes when it is fired is “BANG”. Although the actual sound is different, we have come to associate “BANG” with a gun. This symbolic association of sound which we perceive through vision in the form of a specific word with correct interpretation is hypothesized to be possible because of mirror neurons.
Theory of recursive em bedding
Michael Corballis, an eminent cognitive neuroscientist, argues that what distinguishes us in the animal kingdom is our capacity for recursion, which is the ability to embed our thoughts within other thoughts. “I think, therefore I am” is an example of recursive thought, because the thinker has inserted himself into his thought. Recursion enables us to conceive of our own minds and the minds of others. It also gives us the power of mental “time travel” that is the ability to insert past experiences, or imagined future ones, into present consciousness. Corballis demonstrates how these recursive structures led to the emergence of language and speech, which ultimately enabled us to share our thoughts, plan with others, and reshape our environment to better reflect our creative imaginations. Mirror neurons shape the power of recursive embedding.
Theory of mind
This theory suggests that humans can construct a model in their brains of the thoughts and intentions of others. We can predict the thoughts, actions of others. The theory holds that humans anticipate and make sense of the behavior of others by activating mental processes that, if carried into action, would produce similar behavior. This includes intentional behavior as well as the expression of emotions. The theory states that children use their own emotions to predict what others will do. Therefore, we project our own mental states onto others. Mirror neurons are activated both when actions are executed, and the actions are observed. This unique function of mirror neurons may explain how people recognize and understand the states of others; mirroring observed action in the brain as if they conducted the observed action.
It has been speculated that mirror neurons may provide the neurological basis of human self-awareness. Mirror neurons can not only help simulate other people’s behavior, but can be turned “inward” to create second-order representations or meta-representations of ones own earlier brain processes. This could be the neural basis of introspection, and of the reciprocity of self-awareness and other awareness.
Although the enigma of human brain is unfathomable, but still the indefatigable attempts made by the ever aspiring cognitive neuroscientsts has opened up a realm of metaphysical secrets in the mirror neuron modular brain that has shaped our civilization.
Source of Support: Nil.
Conflict of Interest: None declared.