A dendron is a fundamental neural unit of the cerebral cortex. Distinguished neuroscientist and Nobel Prize winner Sir John Eccles proposes that each of the 40 million dendrons is linked with a mental unit, or psychon, representing a unitary conscious experience. In willed actions and thought, psychons act on dendrons and momentarily increase the probability of the firing of selected neurons, while in perception the reverse process takes place. The mind is split between a material component and a spiritual component—the former influences the latter, but it is the latter that is the true "captain" of our mental processes. The dendrons collectively comprise the material component of the mind, which receives message impulses from the spiritual component through quantum energy, which Eccles calls non-physical etheric energy.