Tuesday, March 22, 2011
This is chiropractic’s greatest challenge and opportunity for increasing human potential.
The central theory of biology is evolution through natural selection. Frankly, if we assume a stationary environment, natural selection improves the ability of an average organism to reproduce fertile offspring. But the internal and external environment is certainly not stationary. Since internal and external resources are limited and finite, organisms evolve as compromises. Most of these compromises can be expressed in terms of energy efficiency. Consequently we arrive at the notion of natural selection as an energy efficiency optimization process. These plastic changes have to happen at the microscopic cellular level (DNA expression) and globally in neural connections and signaling.
Since the CNS controls and regulates all physiological process of the human body, these optimizations must occur at the microscopic cellular level in the nervous system first.
All these changes can be explained by considering the process of energy efficiency of neural communication and neural processing. Energy (available ATP) is finite. It is reasonable to assume that the limiting factor for this energy efficiency optimization process is the use of available ATP and other resources needed by the neuron to process and communicate information. Thus, to optimize neurological programs, the CNS will shunt and mobilize ATP (and other energy resources such as lactate) to the areas of greatest physiological need in the CNS. Or the CNS will ‘turn off’ or mute metabolically expensive processing programs. This is neurophysiological partitioning.
Immediate energy-efficient processing of information can explain seemingly isolated physiological processes. The energy used for signaling (communication & processing) constrains the flow of information within cells and between cells and regions in the CNS.
In the context of energy, neural processing is rather expensive. The adult human brain accounts for 20 percent or more of the body’s total energy use (metabolic costs). In young children, whose brains are nearly as large as an adult, the energy use by this organ can account for nearly 50 percent of the ATP use. Recent studies have shown that 85 percent of the energy used by the brain goes toward restoring the ion fluxes across neuronal membranes that are the biophysical basis of computation and communication in the neocortex. Thus signaling, processing, filtering, controlling, filtering, summing, integrating and management of incoming information account for up to 85 percent of the energy used by the brain.
Thus information processing, although perhaps five or six orders of magnitude more energy efficient than man-made computation, is a considerable expense for the organism.
Energy usage is decisively coupled to neuronal performance in the immediate, during the organism’s lifetime and over the natural selection process over millions of years. The evidence is strong that neuronal processing has evolved to be metabolically efficient.
Because of such energy costs, natural selection has optimized energy use as well as information processing in constructing the way neurons compute and communicate. Our survival and dominance as a species is dependent on the energy efficiency of CNS processing. The large metabolic costs of neural processing and CNS signaling suggest that efficiency is fundamental for survival. Neurons are unable to generate enough energy to meet the requirements of maximal physiological activity. Energy limitation is a factor in shaping the normal operation of the brains circuitry. A process requiring less energy is preferred to a process requiring more energy. The process is forced to become efficient or is eliminated.
Energy metabolism is central to life because cells cannot exist without an adequate supply of ATP. The CNS is particularly sensitive to any disturbances in energy generation and even short term interruption can lead to long lasting damage. Understanding the relations between energy metabolism and function during brain development has not only enormous theoretical but also practical implications for the human race.
This is chiropractic’s greatest challenge and opportunity for increasing human potential. Increasing the efficiency of CNS processing is the chiropractor’s true goal.