The human organism, with all of its various interacting cognitive, emotional, and physiological systems, is a shining example of self-organization and integration across multiple systems. For most of scientific and medical history it has been commonly accepted that the brain is the prime-organizing agent in the human body. It has also been generally accepted that the cognitive and emotional functions of the body exist independent of one another, where the cognitive systems play a more significant role in the overall functioning of the body. However, recent research suggests that while the brain and cognitive systems surely play a vital role in coordinating the various physiological and psychological systems, the heart and emotions may play a much more fundamental role. This paper will attempt to elucidate this core perspective as well as describe the relationship between psychophysiological coherence or emotional/heart coherence and the level of global synchrony and integration of the body as a whole.
    In the 1950's, with such researchers as Walter Cannon, it was assumed that the autonomic nervous system, the heart, and the other organ systems were passive structures merely taking top-down directions from the brain. It was not until the 1970's with John and Beatrice Lacey and eventually French researchers Gahery and Vigier that this foundational assumption began to be challenged. The Lacey's, in their work with the heart, found that it seemed to be sending meaningful messages to the brain, not just passively receiving instructions. In 1974, Gahery and Vigier, working with cats, stimulated the vagus nerve (which carries many of the signals from the heart to the brain) and found that the brain's activity could be reduced by as much as fifty percent (McCraty et al., 2001). There was surely something more complex going on than had previously been thought.
    In 1991, Dr. Armour, an early pioneer in the field of neurocardiology, coined the term "heart brain" to refer to what he considered to be a fully autonomous and complex processing unit. Dr. Armour describes the nervous system as, "A distributed parallel processing system consisting of separate but interacting neuronal processing centers distributed throughout the body” (McCraty et al., 2001). What he has tried to show is that the heart itself has its own intrinsic nervous system that processes information independently of the central nervous system.
Researchers discovered that the heart contains upwards of 40,00 neurons, responsible for detecting circulating hormones and neurochemicals and sense heart rate and pressure information. The cardiac nervous system contains both afferent, local circuit, and efferent parasympathetic and sympathetic neurons. The cardiac ganglia integrate information from the brain and other organ systems, with information received by the cardiac sensory neurons. Once this information is processed, the hormonal and other chemical information is translated into nerve impulses that are sent via several afferent pathways to the medulla in the lower reptilian brain, where it eventually feeds into the intralaminar nuclei of the thalamus and the amygdala. The intralaminar nuclei are directly connected to the frontal lobes and residually to the rest of the cortex, whereby it can effectively synchronize cortical activity.
    While all the physiological, cognitive, and emotional systems are intimately interrelated through ongoing bi-directional communication and feedback, the heart and the emotional systems seem to have a more significant impact on the overall organization and functioning of the human organism as a whole. The reason for this stems from the hearts position as the most powerful and consistent generator of rhythmic information patterns in the body. The heart also possesses the most extensive communication system with the brain and other organs through multiple pathways: neurological, biochemical, biophysical, and energetic. While any node in this complex network of interacting subsystems necessarily exerts an impact on overall organismic functioning, those nodes that maintain multi-level linkages across different subsystems will have a greater influence on the global functioning of the system. It is the proper coordination and synchronization of these linkages that allows for the emergence of higher order functioning. This concept of coherent organization or simply coherence will be discussed in more depth below.
Just as the heart seems to be more primary and influential than the other organ systems, so to do the emotional systems with their relation to the heart seem have a fundamental and perhaps larger effect on the cognitive systems. While bi-directional communication between emotional and cognitive systems are hardwired in the brain, the actual number of neural connections going from the emotional centers to the cognitive centers is higher than going the other way (McCraty et al., 2001).
    But what are emotions to begin with? From this perspective, cognitive and emotional experience is the composite of stimuli from the outside world and internal stimuli in the form of feedback from the other organ systems. From the work of Dr. Karl Pribram, it has been found that these internal and external inputs solidify into psychophysiological patterns in the body over time as certain environments and situations are repeatedly experienced. These patterns are essentially rhythms from the heart, digestive, respiratory, and reproductive systems that are repeated and translated into neural and hormonal activity. When these patterns are repeated enough times they get written into the basic neural circuitry of the brain and become the backdrop by which new information is measured. According to this model when an internal or external stimulus is sufficiently different from the hardwired pattern, the so-called "departure from the familiar" is essentially what creates feelings and emotions (McCraty et al., 2001). Emotions are in essence the subjective experience of this internal physiological mismatch. It is my conjecture that the degree to which an internal or external stimuli is different from ingrained patterns in effect determines the objective arousal level and the subjective or felt intensity of an emotion.
    It has been maintained for thousands of years by numerous cultures across the world that there is a connection between feelings and the specific area around the heart. Why is this? Why do people feel sharp pangs in their chest when they are overcome with sadness or grief? Why did the heart become the universal symbol of love? It is only recently that this intuitive connection has had a valid scientific explanation. The Institute of Heartmath has demonstrated in their 15 years of neurocardiological research that there is a direct connection between different emotions and the rhythmic pattern of heart activity. Using instruments that measure the electromagnetic output of the heart, scientists can actually predict with a very high degree of accuracy the felt emotional state of a person. There is indeed a very real physiological connection between the physical heart and the experience of emotion.
    After analyzing many different physiological measures, the Institute of Heartmath concluded that the natural fluctuations in heart rate, known as heart rate variability (HRV) was most directly associated with the subjective activation of distinct emotional states. More specifically, while changes in heart rate and in the amount of variability can and often do co-vary with emotions, they realized that it is the pattern of the heart's rhythm that is primarily reflective of the emotional state. Also, they realized that the changes in the heart rhythm pattern are independent of heart rate, meaning one can have a high or low heart rate irregardless of the rhythm of their heart wave.
The fact that the Institute of Heartmath found rhythmic activity to be most closely related to emotional activity is not insignificant as it speaks to the very fundamentals of how information is communicated internally amongst the various bodily systems. On an inter-human level, information is communicated via language, symbols, gestures, and various other abstract representations. On the intra-human level, information is communicated by changes in chemical concentrations, the amount of biological activity, and the pattern of rhythmic activity.
Communication, in the way that it is being used here, is referring to, "the process by which meaning is encoded as a message and transmitted in a signal to be received, processed, and comprehended by the various elements of a system." While physiological communication necessarily involves the processing of variation of the amount of chemical or physiological activity, based on the research done by Heartmath, rhythms and patterns of physiological activity appear reflective of a more fundamental order of information communication. Patterns of physiological activity are associated with waveforms of energy that can be measured by external measuring equipment such as the EEG for brain activity and the ECG for heart activity. Physiological information is encoded in waveforms produced by the various neural, chemical, electromagnetic, and oscillatory pressure systems. In this language of waveforms and dynamic patterns, information is encoded by dynamically changing the time interval between bursts of physiological activity. If you graph this change over time you get a sin wave like representation. It is the particular rhythm, pattern, or coherence of this wave that actually communicates encoded physiological information.
    Based on the heart's central role in the network of physiological systems, it is hypothesized that information relative to macro-level integration is encoded in the interbeat intervals of the heartbeat. The means by which this process is carried out is both through neural and hormonal pulses but especially through a near instantaneous energetic communication via the electromagnetic field of the heart. The heart is producing a continuous series of electromagnetic pulses, giving rise to fields within fields of energy, which form interference patterns when they interact with magnetically polarizeable tissues and structures. Further, the waves from the heart interact with the rhythmic waves of the other organs and structures creating additional interference patterns. Based on Karl Pribram's model of bioenergetic information processing (endnote), the Institute of Heartmath has hypothesized that whenever two wave patterns overlap and an interference pattern emerges, the features of each object are encoded and stored in the complexities of the interference wave. The heart produces by far the strongest energy field of any organ or physiological structure, and thus could conceivably act as a global carrier wave for the entire global system. Such a carrier wave would interact with all bodily structures and thus encode all of the rhythmic activity of the body, whereby it would then be able to distribute this information throughout all other systems. This is not to say that other structures are not acting to varying degrees as carrier waves themselves, only that the heart is the most powerful carrier wave and thus likely to distribute information about the highest levels of macro-scopic integration (McCraty et al. 2006).
    With this understanding, what then are the specific qualities of heart waves as they relate to the degree of global synchronization? The rhythm or pattern of heart waves can best be understood in terms of coherence. Coherence in common usage means "the quality of being logically integrated, consistent, and intelligible," (McCraty et al. 2006) though in this particular context coherence will more specifically relates to the three distinct but related concepts used in physics: coherence as global order, coherence as a uniform pattern of cyclical behavior, and coherence as synchronized interactions among multiple systems or more simply global coherence, autocoherence, and cross-coherence.
Global coherence is characterized by a "distinctive organization of parts, the relationship among which generate an emergent whole" (McCraty et al. 2006). This is the primary type of coherence thus far alluded to in this paper. It is through this type of coherence that the emergence of higher levels of organization and functioning are possible. While all systems, to produce any function at all, must have some degree of global coherence, the efficiency of that function depends on what degree of global coherence is present. Systems with high levels of global coherence function very efficiently, while systems with low levels often barely function at all.
Autocoherence on the other hand is a concept used in physics to describe the ordered distribution of energy in a waveform. This form of coherence gets its name because it is a phenomenon unique to individual systems. The degree of autocoherence in a system is measured by the stability of the frequency, amplitude, and shape of the waveform. The greater the consistency or stability of these things, the greater the level of autocoherence.
    Finally, cross-coherence is a concept used to describe the synchronization of multiple systems, where the waves of each system are either phase- or frequency-locked together in their interaction. Multiple systems become synchronized through the process called entrainment, where one rhythmic pattern tends to oscillate at the same frequency as another. Why does one wave entrain while the other is being entrained? Research has shown that the level of autocoherence of a given system directly affects its power to entrain or be entrained, where greater levels of autocoherence tend to entrain other systems towards its pattern.
The term psychophysiological coherence is used to describe the state in which the body is experiencing high levels of all three types of coherence. This state is readily identifiable by measuring and graphing the HRV patterns. The closer a heart wave is to approaching a perfect sin wave, the closer it is to perfect coherence.
With a greater understanding of coherence, the central idea of this paper can be more clearly understood. By seeing the a direct correlation between varying levels of physiological efficiency and synchronization and different levels of heart wave coherence, one can more fully appreciate the fundamental role the hearts plays in the body. The Institute of Heartmath has identified six major categories or modes of psychophysiological function: relaxation, psychophysiological incoherence, psychophysiological coherence, mental focus, emotional quiescence, and extreme negative emotion. Each mode is associated with specific psychological and physiological characteristics, many of which are obvious based on their assigned names.
    While an in-depth look at each mode is beyond the scope of this paper, a simplified understanding of the model can be understood by examining the two poles, psychophysiological coherence and incoherence. Psychophysiological coherence is typified by, "1) resetting of baroreceptor sensitivity, associated with improved short-term blood pressure control and increased respiratory efficiency; 2) increased vagal afferent traffic, associated with the inhibition of pain signals and sympathetic outflow; 3) increased cardiac output in conjunction with increased efficiency in fluid exchange, filtration, and absorption between the capillaries and tissues; 4) increased ability of the cardiovascular system to adapt to circulatory requirements; 5) increased temporal synchronization of cells throughout the body, resulting in increased system-wide energy efficiency and metabolic energy savings" (McCraty et al. 2006). Psychologically, coherence is associated with calmness, emotional stability, improved cognitive functioning, a sense of well-being, heightened intuition and creativity, and positive emotions, such as joy, love, care, and appreciation. Psychophysiological incoherence on the other hand is associated with elevated stress levels and negative emotions, such as anger, frustration, and anxiety, and is generally typified by an erratic and disordered heart rhythm pattern.
    To summarize, the heart and emotional systems play a primary role in integrating and synchronizing the various structures and functions of the human body. The heart, as the most powerful rhythmic generator in the body, communicates with and about the other bodily systems via encoded information in the electromagnetic interference patterns of rhythmic physiological pulsations. When these rhythms are in a state of coherence, the communication within and between systems is much more efficient, resulting in greater levels of cross-system integration and synchronization. The various states of coherency are directly associated with the felt experience of different emotions, and greater psychophysiological coherence can be artificially induced by intentionally arousing positive emotions. While there is still much to be learned about the role of the heart and emotions in the over functioning of the human body, research has evolved to a point where these structures can no longer be ignored as central to global organization and functioning.
      
 
References
Childre, D., & Martin, F. (1999). The Heartmath Solution. San Francisco: Harper.

McCraty, R., Atkinson, M., Tomasino, D., & Bradley, R. (2006) The Coherent Heart. Boulder Creek: Institute of Heartmath.

McCraty, R., Atkinson, M., Tomasino, D. (2001) Science of the Heart: Exploring the Role of the Heart in Human Performance. Boulder Creek: Institute of Heartmath.

McCraty R. (2002). The Energetic Heart: Bioelectromagnetic Interactions Within and Between People. Boulder Creek: Institute of Heartmath.

McCraty R. (2003). Heart–Brain Neurodynamics: The Making of Emotions. Boulder Creek: Institute of Heartmath.