Discussion
In the last 25 years, a variety of new techniques have been introduced as alternatives to more traditional psychotherapies or pharmaceutical interventions for improving mental and emotional imbalances. In addition to the more conventional psychological approaches like cognitive restructuring and neurolinguistic programming, psychologists have employed several techniques from eastern cultures to "still the mind" during a focused meditation period. Yoga, for example, generally focuses on the breath or differing parts of the brain (2), whereas Qigong focuses on the "Dan Tien" point (below the navel). HeartMath techniques, on the other hand, focus on the area of the heart in order to disengage from the racing mind or emotions and shift perception. It is interesting to note that all the above systems focus attention to areas of the body which are known to contain biological oscillators. The heart, brain and intestines [5] all have natural rhythms around 0.1Hz which is the entrainment frequency shown in Figure 1. It appears that these three systems can operate in or out of sync with one another. Further, by the intentional focusing of attention on any one of these systems, their rhythm can be altered. This is at least true for the brain (meditation) and the heart (Freeze-Frame), and most likely true in the case of the gut (Qigong) as well, since the interaction of the sympathetic and parasympathetic nervous systems innervates and affects its rhythms [23]. Figure 2 shows an almost hundred fold increase in the MF signal power after the FF-intervention and a correlated 4 to 5 fold increase in the EEG signal power for that same frequency. If this EEG signal was associated with direct radiation from the heart, one would expect the increases to be in the ~1.0-1.5 Hz range (R-R wave frequency) rather than the ~0.1 Hz range (baroreceptor frequency). Our present hypothesis is that a strong and sustained increase in baroreceptor system activity leads to a greatly increased coupling between the heart (HRV) and the brain (EEG) via nerve conducted signals. Independent brain oscillator capability in the ~0.1 Hz range appears to exist as illustrated in Figure 2a before FF; however, strong baroreceptor signals appear to be able to resonate these brain oscillation modes to greater amplitudes. The data of Figure 5 tend to support this position in that different portions of the brain do not always simultaneously exhibit entrainment in this narrow frequency range. The activity recorded from any particular EEG electrode location tends to wander in and out of entrainment over time (some more than others). The data of Figure 4 also supports this view in that, for some individuals, very large power density is present in this frequency range even when the heart is not functioning in the entrainment mode. Perhaps one of the lessons to be learned here is that one should not consider the electrical output of the brain in isolation from the other major biological oscillators of the body since they all form a coupled system.

Although one can certainly see how a strong ~0.1Hz signal traveling from the heart to the brain via the baroreceptor link might frequency-pull the sympathetic and parasympathetic branches of the ANS into this frequency range and also frequency-pull the respiratory system into the same range, it is not so clear where this ~0.1 Hz baroreceptor signal originates. We propose that Figure 2a needs to be altered to include an intentionality source, which exists at a more subtle level than the physical, and it is this source that pumps the initiating ~0.1 Hz signal into the baroreceptor channel heading for the brainstem. Figure 10 provides a pictorial representation of this speculative modeling.

In the evoked potential study, the EEG was averaged, synchronized to the R-wave of the ECG as can be seen in Figure 8. From the hemodynamics, the associated blood pressure pulse, seen with the ear lobe measurement, is detected in the evoked potential trace 240 ms later (see bottom of Figure 8). This blood pressure pulse was clearly manifested in the O1 and O2 plots of Figure 8 but not in the waterfall evoked potential traces of Figure 9a before the FF intervention. After the FF intervention, a rather abrupt transition appeared in the waterfall traces with a fairly rapid shift to a trace that closely approximates that of the last trace in Figure 9a. This contrast is apparent in Figure 9b which reproduces the first and the last trace of figure 9a. This data is very important in that it shows how rapidly the evoked potential can reflect changes in the functioning of the heart.

With the present experiments, we are unable to make any unequivocal statements concerning the presence or absence of pacemaker cells in the brain; however, the neural network appears capable of stable oscillation in the ~0.1 Hz range.

Although the issue of the individual’s perceptual change, that occurs in association with the entrainment mode of heart function, needs to be discussed, electrophysiological monitoring alone does not provide the appropriate data base for meaningful evaluation. Short term psychological tests are needed to discriminate the perceptual changes associated with the FF intervention experience. Although a single or several simultaneous sensory information inputs lead to a particular perception, and integration of a number of perceptions leads to awareness, the latter is only one facet or correlate of consciousness. Clearly, we have a long way to go before the full scope of head/heart entrainment can be understood.