In prior posts (here and here), we have learned of the non-toxic, anti-cancer and anti-aging ("free-radical scavenger") properties of a typical component of the cannabis ("marijuana") plant called cannabidiol (CBD). We have also learned through review of some animal research that CBD is associated with the growth of new neurons in the brain. At this juncture, let me explicitly enunciate that the human body and, in specific, the brain are in actuality very elastic. I mentioned previously that it has been demonstrated that humans can and do build new neural pathways as has been again shown through the clinical application of computer-aided biofeedback technology in brain rehabilitative therapy and cognitive performance enhancement. The growth rates of cells and tissues (some organs are heterogeneous cell collections while others are not) of the body vary. For instance, in an adult human it can take about six months after a root canal for the bone cells to fill the holes left from the tooth extraction. Next, there tends to be the popular notion that the brain is the control center of the body. The fact of the matter is that it is not.

In 1915, Walter Bradford Cannon, M.D., discovered the stress response– changes in emotions are accompanied by predictable changes in heart rate, blood pressure, respiration and digestion– and thereby made a significant contribution to psychology and medicine. However, Cannon presumed that the brain was in control of the entire process.

In 1960s and 1970s John and Beatrice Lacey were some of the first modern psychophysiological researchers to examine information flow between the brain and the heart and observe that the heart communicates with the brain in ways that significantly affect human perception and reactions to the world. In 1974, French neurophysiologists Gahery and Vigier discovered a neural pathway and mechanism whereby input from the heart to the brain could "inhibit" or "facilitate" the brain’s electrical activity ("Inhibitory effects in the cuneate nucleus produced by vago-aortic afferent fibers." Brain Research. Volume 75, Issue 2, 26 July 1974, Pages 241-246. DOI:10.1016/0006-8993(74)90744-6.). Working with cats, Gahery and Vigier stimulated the vagus nerve and found that the brain’s electrical response was reduced to about half its normal rate. Therefore, the new evidence suggested that the heart and nervous system were not simply following the brain’s directions as previously assumed since Cannon.

In 1991, an early pioneer in neurocardiology, Dr. J. Andrew Armour, introduced the concept of a functional "heart brain." Armour found that:

The heart’s nervous system contains around 40,000 neurons, called sensory neurites, which detect circulating hormones and neurochemicals and sense heart rate and pressure information. Hormonal, chemical, rate and pressure information is translated into neurological impulses by the heart’s nervous system and sent from the heart to the brain through several afferent (flowing to the brain) pathways. It is also through these nerve pathways that pain signals and other feeling sensations are sent to the brain. These afferent nerve pathways enter the brain in an area called the medulla, located in the brain stem. The signals have a regulatory role over many of the autonomic nervous system signals that flow out of the brain to the heart, blood vessels and other glands and organs. However, they also cascade up into the higher centers of the brain, where they may influence perception, decision making and other cognitive processes.

The new research showed that the brain and nervous system was really a "distributed parallel processing system" composed of distinct but interplaying groups of neuronal processing centers disbursed throughout the body. Further, the heart had its own built-in nervous system that functions and processes information independently of the brain or the previously identified nervous system (e.g. why a heart transplant works; also see "The heart reinnervates after transplantation." Ann Thorac Surg 2000;69:1769-1781.).

Another piece of the heart-brain communication puzzle was provided by research on the hormonal system. In 1981, the heart was reclassified as an endocrine or hormonal gland when Atrial Natriuretic Factor (ANF) was isolated. ANF, a hormone produced and excreted by the heart, has a regulatory effect on the blood vessels, the kidneys and the adrenal glands and a large number of regulatory regions in the brain.

Dr. J. Andrew Armour and research team found that the heart contains a cell type known as "intrinsic cardiac adrenergic" (ICA) cells ("Capacity of intrinsic cardiac neurons to modify the acutely autotransplanted mammalian heart." J Heart Lung Transplant. 1994 Sep-Oct;13(5):847-56.). Such cells are considered "adrenergic" because they synthesize and release catecholamines (norepinephrine and dopamine), neurotransmitters previously thought to be produced only by neurons in the brain and ganglia outside the heart. An even more recent discovery is that the heart also secretes oxytocin, the "cuddle" or "love" hormone. Beyond its well-known functions in childbirth and lactation, recent evidence indicates that this hormone is also involved in cognition, tolerance, adaptation, complex sexual and maternal behaviors as well as in the learning of social cues and the establishment of enduring pair bonds. Concentrations of oxytocin in the heart are as high as those found in the brain (also see "Chronic Oxytocin Treatment Mediates Heart Rate Responses Following Social Isolation." 2007).

These findings show that the heart is actually:

a highly complex, self-organized information processing center with its own functional "brain" that communicates with and influences the cranial brain via the nervous system, hormonal system and other pathways. These influences profoundly affect brain function and most of the body’s major organs, and ultimately determine the quality of life.

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[w]hile two-way communication between the cognitive and emotional systems is hard-wired into the brain, the actual number of neural connections going from the emotional centers to the cognitive centers is greater than the number going the other way. [This in part explains] the tremendous power of emotions, in contrast to thought alone. Once an emotion is experienced, it becomes a powerful motivator of future behaviors, affecting moment-to-moment actions, attitudes and long-term achievements. Emotions can easily bump mundane events out of awareness, but non-emotional forms of mental activity (like thoughts) do not so readily displace emotions from the mental landscape.

So, an even more sophisticated application of recent research beyond the aforementioned computer-aided cranial brain-centric biofeedback technique is the self-moderated biofeedback technique of "meditation" or "psychophysiological coherence":

[..] individuals can gain more conscious control over the process of creating increased coherence within and between the mental and emotional systems than might be commonly believed. This, in turn, can lead to greater physiological coherence, manifesting as more ordered and efficient function in the nervous, cardiovascular, hormonal and immune systems. We call the resulting state psychophysiological coherence, as it involves a high degree of balance, harmony and synchronization within and between cognitive, emotional and physiological processes. Research has shown that this state is associated with high performance, reduced stress, increased emotional stability and numerous health benefits.