Restoring the Brain

Neurofeedback as an Integrative Approach to Health

Hanno W. Kirk, Hanno W. Kirk

• Éditeur: Routledge
• Année: 2020
• ISBN:
  9781000767230
• Édition: 2
• Sujet: Medicina
• Sous-sujet: Psiquiatría y salud mental

This thoroughly updated second edition of Restoring the Brain is the definitive book on the theory and the practice of Infra-Low Frequency brain training. It provides a comprehensive look at the process of neurofeedback within the emerging field of neuromodulation and essential knowledge of functional neuroanatomy and neural dynamics to successfully restore brain function.

Integrating the latest research, this thoroughly revised edition focuses on current innovations in mechanisms-based training that are scalable and can be deployed at any stage of human development. Included in this edition are new chapters on clinical data and case studies for new applications; using neurofeedback for early childhood developmental disorders; integrating neurofeedback with psychotherapy; the impact of low-frequency neurofeedback on depression; the issue of trauma from war or abuse; and physical damage to the brain.

Practitioners and researchers in psychiatry, medicine, and behavioral health will gain a wealth of knowledge and tools for effectively using neurofeedback to recover and enhance the functional competence of the brain.

Part I

Development, History, and Theory of Neurofeedback

Chapter 1

Changing the Paradigm from Neurochemical to Neuroelectrical Models

Hanno W. Kirk

Communication patterns in the brain are mediated by chemical and electrical signals. Because of the enormous clinical and commercial potential of psychiatric medications thus far, only the chemical paradigm has received significant interest from the scientific community. The electric patterns in the brain have been almost entirely ignored.

Bessel A. van der Kolk,¹ Author of the Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma

1.1 The Early Days of Speculation

Our understanding of how the brain functions has changed dramatically over the centuries. Through much of time the heart was celebrated as the central locus of thought, emotions, and even the soul. The contents of the skull were regarded as an undifferentiated biomass. While an ancient Egyptian papyrus, attributed to a battlefield surgeon, noted that head trauma affected physical function, there was no anatomical knowledge of the brain. In the 1st century bc, Greek philosophers theorized that the brain was where the mind was located, and that it might be the seat of sensations. In the 2nd century ad, the great Roman physician and anatomist Galen used dissection and produced detailed hand-drawn maps of the brain and the spinal cord. Galen believed that soul and mind consisted of pneumo, or spirits emanating from the heart, and that the role of the brain was to ennoble these spirits in human beings. Galen’s “hydraulic” view of spirits moving around the body like fluids was to dominate thinking into the Renaissance.²

The intensely curious Renaissance genius Leonardo da Vinci used anatomical dissection to study all parts of the body, including the brain. He left behind beautifully detailed and accurate anatomical drawings of the brain, including the cavities, or ventricles. Da Vinci’s slight departure from the heart-centered spirits view was his belief that perception and cognition resided not in the brain “substance” itself, but in these cavities. Without modern tools, however, he and others could only speculate. A radical departure from this spirit-dominated view of the body came in the 17th century, when Rene Descartes declared that the mind and the body were distinct. This dualistic view has largely dominated Western medical thinking ever since. Even today it seems to inform how the brain is seen as an organ driven by biochemical actions, yet somehow separate from the myriad of mental activities sparked by electrical networks. Brain surgeons and neurologists look at neurological dysfunctions in terms of a physical pathology, but only minimally concern themselves with mental health issues deriving from these conditions.

Psychiatrists, in turn, tend to look at mental dysfunctions with little understanding of how they are impacted by dysregulation of the neural networks in the brain, as well as by biomedical issues in other parts of the body, like the gut. Part of the effort of this book is to move away from this arbitrary dualistic view and instead take an integrative view of mind and body, one that recognizes that seamless interplay between physical and mental health can be used for enhancing overall functioning.

Modern understanding of the nervous system, and later of brain functions, had to await the technological advances in the 19th and 20th centuries. In succession, they were the invention of the microscope; the development of the Golgi staining method for nerve tissue; the development of a refined sensitive galvanometer for measuring the electrical action potentials in the nerves; the invention of micropipettes; and, ultimately, the appearance of the electron microscope in 1950. Each of these breakthroughs allowed for more detailed examination of theories and assumptions that had previously been based on speculation.

In the 1880s, Italian scientist Camillo Golgi invented a silver chromate staining solution that made the study and identification of neural tissue in the spinal cord and in muscular tissue possible for the first time under the microscope. However, because he was limited by the low amplification of microscopes in the 1890s, Golgi drew a critical conclusion that turned out to be incorrect. He believed that the nerve tissue he was identifying with his staining technique was comprised of a seamless network (reticulum) through which nerve impulses could travel in either direction. This became known as the Reticular Theory.³

At about the same time, Spanish pathologist Santiago Ramon y Cajal, using Golgi’s new staining technique, came to a completely different conclusion. He was able to identify and follow individual long axons to their termination. Through this, he demonstrated that the neuron was the principal structural and functional unit of the nervous system. This became known as the Neuron Doctrine.⁴ This doctrine states that each nerve cell is separate and individual, bounded like all other cells in the body by its plasma membrane. He argued that the junction (or synaptic gap) between neurons was essential in regulating the transmission of signals in the nervous system. From his discovery of the axonal growth cone, he experimentally demonstrated that the relationship between nerve cells was contiguous, rather than continuous as Golgi had supposed.⁵ The Neuron Doctrine was initially very controversial and was opposed by Golgi and other histologists, who continued to defend the Reticular Theory past the turn of the 20th century.^{6, 7}

However, Cajal’s discoveries, including his detailed drawings and lucid prose explanations, had a major influence on the work of British physiologist Charles ­Sherrington. After meeting Cajal in Spain, Sherrington turned his attention to the connection between the brain and the spinal cord. He observed that signal conduction in the long nerve trunks of the spinal cord was much faster than in the grey matter of the brain. To explain the differential in the speed of conduction, Sherrington hypothesized that neurons had to have gaps between them, to which he gave the term “synapse” in 1897. He argued that the synaptic gap between neurons was essential in the regulation of the transmission of signals in the nervous system.⁸ If a synaptic gap existed, then the burning question became what was happening at this gap?

In 1921, the Austrian pharmacologist Otto Loewi, inspired by a dream, conducted experiments on the vagus nerve of frog hearts. He found that during the stimulation of the vagus nerve, a substance was formed. From these experiments, he concluded that neurohumoral substances were critical in nerve transmission, but it was difficult to identify this vagus-stimulating neurohumoral substance, which turned out to be acetylcholine (ACH). As Loewi later realized, the difficulty was that “acetylcholine produces only a very short-acting effect [and] is speedily metabolized.” This is why other scientists had trouble replicating his findings.⁹ The problem of proving the existence and function of these seemingly ephemeral substances, which later became known as neurotransmitters (NTs), turned into a 40-year scientific quest to determine what role these chemical substances played in neurotransmission.

Another group of scientists believed that the transmission of the nerve impulses was accomplished simply by electrical “sparks” flying across the synaptic gaps from one neuron to another. The idea of electrical transmission was seemingly substantiated by the work of German physiologist Emil du Bois-Reymond. After inventing a highly refined and sensitive galvanometer, he was able to observe that nerve impulses were accompanied by electrical discharges. He identified that there could be fluctuations of these discharges from negative to positive, and back again. He found that this corresponded to variation in the action potential as nerve impulses traveled from the brain and through the spinal cord to cause muscle contractions. With only low-amplification microscopes and crude measuring tools, du Bois-Reymond could only speculate on the mystery of how this nerve transmission was accomplished. In a textbook of the time, he wrote:

Of known natural processes that might pass on excitation, only two are, in my opinion, worth talking about – either there exists at the boundary of the contractile substance – a stimulating secretion … or the phenomenon is electrical in nature.¹⁰

Even though du Bois-Reymond considered that chemical change was part of muscle contraction, he did not consider that the transmission between nerve and muscle was chemical. Based on his observations with the galvanometer, du Bois-Reymond tended to place more emphasis on the concept of electrical transmission. Indeed, he became known as the father of the field of electrophysiology.¹¹

1.2 The Soups and the Sparks

Du Bois-Reymond’s speculation that the process might be either chemical or electrical had defined the debate over the nature of neural transmission that was to continue over the next 60 years. Elliott Valenstein called the debate between the two scientific camps The War of the Soups and the Sparks (2005). The chemists and pharmacologists argued for the primacy of neurohumoral secretions in triggering neurotransmission.¹² The physiologists proposed that nerve conduction was achieved primarily by electrical impulses traveling along neural pathways and then into the muscles.

At the beginning of the 20th century, the intensive study of the nervous system by various eminent scientists produced exciting speculation and debate about which side was right. The research on the autonomic nervous system conducted between 1890 and 1920 laid the foundations for later studies on the role of chemicals. Two well-known anatomists, Walter Haskell and John Langley, conducted research at Cambridge University that led to the discovery of the sympathetic and parasympathetic nervous systems. Their studies, and those of Wilhelm Feldberg, led to the positive identification of ACH at the junction of motor neurons and muscle when the muscle contracted. Much of the systematic search for evidence to support chemical transmission of nerve impulses was conducted under the leadership of Henry Dale at the Institute of Medical Research outside London.¹³ A spirited debate developed between the “Soups” group, headed by Dale, and the “Sparks” group, whose most prominent proponent was the Australian physiologist John Eccles. Eccles did not believe that the “ACH hypothesis”, derived from Feldberg’s work with parasympathetic ganglia, applied to the central nervous system. The neurophysiologists, who recorded electrical impulses with a multistage vacuum tube that displayed on fast-responding cathode ray oscilloscopes, were sure that their impressive visual data proved that neurotransmission was electrical. As Valenstein records, there was “also a tendency of the neurophysiologists to look down on the pharmacologists, who spent their time investigating ‘spit, sweat, snot and urine’.”¹⁴ The principal flaw in the Sparks hypothesis was that neurotransmission did not occur at the speed of electrical transport. To account for this discrepancy, Eccles came up with various explanations that seemed plausible at the time. He cleverly proposed that “wave interference” slowed the transmission. He also attempted to explain the excitation and inhibition phenomenon were caused by “eddy currents” of different polarities. Then, in 1947, he posited a new theory based on a dream. He claimed that interneurons (previously identified with the Golgi staining method) were responsible for producing inhibition at the synapse level.

Four years later it was Eccles who disproved his own theory and confirmed the chemical neurotransmission theory. Two technological advances allowed for this. In 1950, magnification provided by the electron microscope brought into view individual cells and even the...