Cybernetic Approach
The cybernetic approach to EMF-induced biological effects begins with a view of the living system as a black box. The animal is considered to have an unknown internal organization, and the only factors regarded as accessible to investigation are the applied EMF (input) and the biological effect (output). Empirical data that describe relationships between various inputs and outputs is generalized into empirical laws that furnish insights into the relevant component processes. The empirical laws cannot conflict with known physical law, but they need not conform to a process or behavior observed only in a model system. The reports described in the preceding chapters provide a basis for this approach, and they may be summarized this way:
I. EMFs can alter the metabolism of all body systems, including the nervous, endocrine, cardiovascular, hematological, immune-response, and reproductive systems.
2. The effects on each tissue or system are largely independent of the type of EMF. The studies suggest that there are common physiological pathways for spectrally different EMFs, and that the major consequence associated with specificity of the EMF is that it determines the magnitude or direction-as opposed to the existence-of the biological effect. On the other hand, certain spectral characteristics-pulse modulation frequency seems to be one of the most important-can fundamentally modify the biological response.
3. An organism's response to an EMF is determined in part by its physiological history and genetic predisposition; individual animals, even in an apparently homogeneous population, may exhibit changes in opposite directions in a dependent biological parameter.
4. Although high-field-strength and long-duration studies are exceptions, EMF-induced biological effects seem best characterized as adaptive or compensatory; they present the organism with an environmental factor to which it must accommodate.
If attention were restricted to EMF-related changes in individual body systems such as intermediary metabolism, the immune-response system, or the adrenal gland, it might be hypothesized that the action of the field involved certain enzymes, specific antibody regions of certain cells or particular organs. But the studies clearly showed that EMFs produce a complex interrelated series of physiological changes (see Figure 8.4). It follows that the consequences of EMF exposure must be understood in terms of an integrative response of the entire organism. In our view, after the EMF is detected, information concerning it is communicated to the central nervous system which then activates the broad array of physiological mechanisms that are available to furnish a compensatory response (Fig. 9.1). As is generally true of an adaptive response, the particular biological system that is invoked, and the nature of its response, will depend on numerous factors including the animal's internal conditioning and its external environment. With one notable exception, the biological processes that follow detection of an EMF are the same as those associated with the response to any biological stressor. Thus, for example, the cellular or molecular mechanisms that operate in the adrenal following a cold stress to produce altered serum corticoid levels will also operate following an electromagnetic stress, because adrenal activity is initiated by neuronal and hormonal signals, not by the actual presence of the stressor agent in the tissue. Thus, advances in the understanding of EMF-induced systemic effects are tied to general progress in physiology. Even so, electromagnetic stress has a characteristic which sets it apart from other stressors: electromagnetic stress is not consciously perceived. This suggests that sub-cortical brain centers are the first mediators of the electromagnetic stress response. The physical processes that occur in this as-yet-unidentified center must, therefore, be different than those associated with the mediation of other stressors -heat, cold, trauma, for example- all of which are detected peripherally and are then consciously perceived.
Fig. 9.1. The basic control system that mediates EMF-induced biological effects. The field is detected and transduced into a biological signal which is received in the CNS. The resulting hormonal and electrical signals to the various body systems initiate the appropriate adaptive physiological responses.
Bearing in mind the studies described in part two of this book, it can be concluded that the adaptive response occurs primarily when the EMF is outside the frequency range to which the organism is intrinsically sensitive. Inside the range, the EMF can supply information to the organism concerning its environment.