The Thinking Heart:
12 June 2009
By Steven JamesAnt's may not strike you as the representation of wisdom. Their brains have only 10,000 neurons, nevertheless they are noted for their problem solving abilities. They construct complex dwellings using tools, their society is intricate with a caste system, additionally they know of war and politics.
Ants developed agriculture millions of years before humans, and communicate elaborate information through diverse means (sound, smell, body language). In short, 10,000 neurons is enough for the operation of a complicated society.
Now consider this, there are 40,000 neurons in human heart. That is more than sufficient to make a brain. If an ant brain possesses the capacity for almost 50 million neural connections, your heart brain has close to 800 million. No surprise that the ‘heart’s brain’ is a system so sophisticated, that it is able to sense, learn and recollect.
Because evidently, our heart actually stores its own memories. Additionally, it may very well be involved in dreaming activity. Our ‘two brains’ are in constant communication and they clearly affect each other. For example, stress coming through the brain may affect your cardiac rhythm, but it is also true the other way around. Some information may be perceived through the heart, and only then communicated to the brain.
For ages, the heart has been considered the cradle of emotion, courage and wisdom. At the Institute of HeartMath (IHM) Research Center, they are investigating the physiological mechanisms by which the heart communicates with the brain, thereby influencing information processing, perceptions, emotions and well-being.
Some of the first contemporary psychophysiological researchers to examine the conversations between the heart and brain were John and Beatrice Lacey. During 20 years of research throughout the 1960s and ’70s, they determined that the heart communicates with the brain in ways that significantly affect how we perceive and respond to the world.
A generation before the Laceys began their research, Walter Cannon had shown that deviation in emotions are accompanied with predictable changes in heart rate, blood pressure, respiration and digestion. In Cannon’s view, when we are "aroused", the mobilizing part of the nervous system ( sympathetic ) energizes us for fight or flight, and in more placid moments, the calming part of the nervous system ( parasympathetic ) calms us down. In this view, it was presumed that the autonomic nervous system and all the physiological responses moved in concert with the brain’s reaction to a given stimulus. Presumably, our inner systems tooled up together when we were aroused and simmered down together when we were at rest, and the brain was in control of the entire process.
The Laceys noticed that this simple model only partially matched actual physiological behavior. As their investigation evolved, they found that the heart seemed to have its own peculiar logic that frequently diverged from the direction of the autonomic nervous system. The heart appeared to be sending significant messages to the brain that it not only comprehended, but obeyed. Even more intriguing was that it looked as though these messages could affect a person’s conduct. Shortly after this, neurophysiologists discovered a neural pathway and mechanism whereby input from the heart to the brain could "inhibit" or "mitigate" the brain’s electrical activity.
Then in 1974, the French researchers Gahery and Vigier, working with cats, stimulated the vagus nerve and determined that the brain’s electrical response was reduced to about half its normal rate. In summary, evidence alluded that the heart and nervous system was not simply following the brain’s directions, as Cannon had theorized.
While the Laceys were conducting their research in psychophysiology, a small group of cardiovascular researchers joined with a similar band of neurophysiologists to explore areas of mutual curiosity. This represented the conception of the new discipline of neurocardiology, which has since contributed critically important insights into the nervous system within the heart and how the brain and heart communicate with each other via the nervous system.
After extensive research, one emerging trailblazer in neurocardiology, Dr. J. Andrew Armour, introduced the concept of a functional "heart brain" in 1991. His work revealed that the heart has a perplexing intrinsic nervous system that is sufficiently sophisticated to qualify as a "little brain" in its own right. The heart’s brain is an intricate network of numerous forms of neurons, neurotransmitters, proteins and support cells like those identified in the brain proper. Its elaborate circuitry empowers it to act independently of the cranial brain to comprehend, remember, and sense. The recent book Neurocardiology , edited by Dr. Armour and Dr. Jeffrey Ardell, provides a comprehensive overview of the function of the heart’s intrinsic nervous system and the role of central and peripheral autonomic neurons in the regulation of cardiac function.
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 details. Hormonal, chemical, rate and pressure information is translated into neurological stimuli 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 conveyed to the brain. These afferent nerve pathways access 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. Furthermore, they also cascade up into the higher centers of the brain, where they may sway perception, decision making and other cognitive processes.
Dr. Armour describes the brain and nervous system as a distributed parallel processing system consisting of separate but interacting groups of neuronal processing intersections dispersed throughout the body.
The heart has its own intrinsic nervous system that operates and processes information independently of the brain or nervous system. This is what enables a heart transplant to work: Normally, the heart communicates with the brain via nerve fibers running through the vagus nerve and the spinal column.
In a heart transplant, these nerve connections do not reconnect for a prolonged period of time, if at all. Nevertheless, the transplanted heart is able to function in its new host through the capacity of its intact, intrinsic nervous system.
The Thinking Heart Part2
