ABSTRACT
Brain signals are electrical signals or impulses moving from neuron to neuron throughout our elaborate web of brain circuitry. However, the passage of electrical impulses along neuronal wires in the brain is very different from electricity passing through a copper wire such as used in our houses. Perhaps the greatest difference is that “wires” in the brain and nervous system are surrounded inside and out by a watery milieu, a condition that would instantly short-circuit the passage of electricity along a copper wire. Thus, a radically different electrical design is needed by neurons. Evolution has honed a remarkable oil-based “wire,” the axon, enabling electrical ¦ow from neuron to neuron. However, electrical transmission as occurs in our brain is faced with a huge handicap. Speed of electrical ¦ow through neural connections is dramatically slower compared to electrical transmission lines. This slow pace of bioelectrical transmission has never been fully overcome (Fox, 2011), although numerous evolutionary adaptations have occurred toward maximizing brain speed. In other words, brain speed seems to have maxed out in humans. Recall from Chapter 1 that oils or lipids are the predominant structural molecules in our neural wires. It is now clear that Mother Nature tinkered with every conceivable class of biological raw material, especially fatty acids, as building blocks toward maximizing brain speed along axon/ synaptic circuits (Crawford et al., 1999; Cunnane and Crawford, 2003; Cunnane and Stewart, 2010). It is also clear that our survival as a species is tied in no small way to Mother Nature’s selection of DHA for optimizing speed of our neurons. But speed is only one of several key biochemical parameters needed in neuron membranes. Energy is often in short supply because of its prodigious consumption in neurons. Consequently, neurons are under great selective pressure not only to produce as much energy as possible but also to build transmission lines that conserve energy.
