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" It is pretty clear, then, that attention can control the brain’s sensory processing. But it can do something else, too, something that we only hinted at in our discussion of neuroplasticity. It is a commonplace observation that our perceptions and actions do not take place in a vacuum. Rather, they occur on a stage set that has been concocted from the furniture of our minds. If your mind has been primed with the theory of pointillism (the use of tiny dots of primary colors to generate secondary colors), then you will see a Seurat painting in a very different way than if you are ignorant of his technique. Yet the photons of light reflecting off the Seurat and impinging on your retina, there to be conveyed as electrical impulses into your visual cortex, are identical to the photons striking the retina of a less knowledgeable viewer, as well as of one whose mind is distracted. The three viewers “see” very different paintings. Information reaches the brain from the outside world, yes—but in “an ever-changing context of internal representations,” as Mike Merzenich put it. Mental states matter. Every stimulus from the world outside impinges on a consciousness that is predisposed to accept it, or to ignore it. We can therefore go further: not only do mental states matter to the physical activity of the brain, but they can contribute to the final perception even more powerfully than the stimulus itself. Neuroscientists are (sometimes reluctantly) admitting mental states into their models for a simple reason: the induction of cortical plasticity discussed in the previous chapters is no more the simple and direct product of particular cortical stimuli than the perception of the Seurat painting is unequivocally determined by the objective pattern of photons emitted from its oil colors: quite the contrary. "
― Jeffrey M. Schwartz , The Mind and the Brain: Neuroplasticity and the Power of Mental Force
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" Let’s take the example of a person suffering from OCD. In this case, one possible brain state corresponds to “Wash your hands again.” Another is, “Don’t wash—go to the garden.” By expending mental effort—or, as I think of it, unleashing mental force—the person can focus attention on this second idea. Doing so, as we saw, brings into play the Quantum Zeno Effect. As a result, the idea—whose physical embodiment is a physical brain state—“Go to the garden” is held in place longer than classical theory predicts. The triumphant idea can then make the body move, and through associated neuroplastic changes, alter the brain’s circuitry. This will change the brain in ways that will increase the probability of the “Go to the garden” brain state arising again. (See schematic on Chapter 10.) "
― Jeffrey M. Schwartz , The Mind and the Brain: Neuroplasticity and the Power of Mental Force
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" The cortex, that is, is as subject to remapping through attention as it is through the changes in sensory input described in our survey of neuroplasticity. In addition, in all three of the cortical systems where scientists have documented neuroplasticity—the primary auditory cortex, somatosensory cortex, and motor cortex—the variable determining whether or not the brain changes is not the sensory input itself but, crucially, the attentional state of the animal. In 1993 Merzenich showed that passive stimulation alone simply did not cut it. He and his students repeatedly exposed monkeys to specific sound frequencies. When the monkeys were trained to pay attention, the result was the expected tonotopic reorganization of the auditory cortex: the representation of the repeatedly heard frequency expanded. But when the monkeys were distracted by another task, and so were paying little or no attention to the tones piped into their ears, no such tonotopic expansion occurred. Inputs that the monkey does not pay attention to fail to produce long-term cortical changes; closely attended behaviors and inputs do. Let me repeat: when stimuli identical to those that induce plastic changes in an attending brain are instead delivered to a nonattending brain, there is no induction of cortical plasticity. Attention, in other words, must be paid. "
― Jeffrey M. Schwartz , The Mind and the Brain: Neuroplasticity and the Power of Mental Force
