The K-Complex: A 7-Decade History

The K-complex was first described by Loomis et al 67 years ago in a paper that was one of a series of seminal studies of sleep conducted in Loomis' private laboratory. The study of the K-complex was almost immediately taken up by many notable figures in early electroencephalography research, such as Robert Schwab, Mary Brazier, and W. Gray Walter. More than 200 papers have been published in the years since these early studies, including major reviews in 1956 by Roth et al and in 1985 by Peter Halász. More recently, K-complex study has been taken up by event-related potentials researchers such as Ken Campbell and animal neurophysiologists such as Florin Amzica and Mircea Steriade. The present paper provides a historical and thematically based review of the K-complex literature and attempts to integrate the various theoretical positions and neurophysiologic data. Specifically, K-complexes are discussed in terms of their relationship to other electroencephalographic phenomena, their relationship to autonomic activation, their role in the study of information processing during sleep, and what is understood of their underlying neurophysiology.

From single-channel recordings to brain-mapping devices: the impact of electroencephalography on experimental psychology

Since its discovery in 1920, the electroencephalogram (EEG) has become a widely used tool in experimental psychology. Although originally the merits of the method were seen first of all in an improvement of medical diagnostics it was soon understood by psychologists that EEG can also be used to study psychic processes in healthy participants. This article summarizes important events in the history of EEG research that laid the ground for this development, as fast Fourier transformation to analyze the spontaneous activity and signal averaging to improve the signal-to-noise ratio. The article shows how general technological developments were the prerequisite for these methodological improvements in EEG research and how they inspired new research questions. Key discoveries that proved unequivocally that psychic processes do become manifest in EEG signals are briefly reviewed, and the emerging paradigm of cognitive psychophysiology, which is closely linked to the development of EEG research, is described.

Writing brains: tracing the psyche with the graphical method

At the end of the 19th century, the graphic method kindled attempts to use it for investigating psychic processes. In Germany, Hans Berger took up this line of research, later to become the pioneer of electroencephalography (EEG). This trajectory of Berger's work is analyzed as an "enabling constraint" guiding him toward the EEG at a time when nobody else was pursuing this line of research and also causing serious methodological problems. In the epistemological perspective of this analysis, many of his problems extend beyond the local context of his work and point toward ambiguities surrounding the project to trace the psyche with the graphic method. From the mid-1930s, the EEG inspired ongoing attempts to decipher the specific meanings of these recordings, and large ensembles of machinery were mobilized, molding concepts of the psyche according to the results and the specifications of the graphic method.

[Hans Berger (1873-1941)--the history of electroencephalography]

The discovery of electroencephalography (EEG) in 1929 by the German psychiatrist Hans Berger was a historical breakthrough providing a new neurologic and psychiatric diagnostic tool at the time, especially considering the lack of all those now available in daily practice (EP, CT, MRI, DSA, etc.) whithout which the making of neurologic diagnosis and planning neurosurgical operative procedures would now be unconceivable. There are no recent reports on the topic in the Croatian medical literature. The methods used in the study included search through previous reports, bibliographic notes, Internet sources, and analysis of continuous scientific attempts made through centuries to discover the real nature and meaning of electrical activity. Galvani's accidental discovery of "biological electricity" led to Volta's discovery of the battery (voltaic pile). Using it, Rolando was the first to stimulate cerebral surface. Thus, enabling Fritsch and Hitzig and Ferrier to develop the idea of cerebral localization (Jackson, Gowers, Gotch and Horsley). It was understandable that brain electrical stimulation produces contralateral motor response, but it was unknown whether there was a spontaneous (intrinsic) brain electrical current that could be recorded. Caton was the first to report on the "current in the brain gray substances onto open brain. Based on Caton's discovery and of those of Beck, Danilevsky, Prawdicz-Neminsky and others, Berger made the first EEG (electrocorticogram) recording on July 6, 1924, during a neurosurgical operation on a 17-year-old boy, performed by the neurosurgeon Nikolai Guleke. He reported on the topic in 1929, using the terms alpha and beta waves. The "spike and waves" (Spitzenwellen) were described shortly thereafter by the American group of EEG pioneers (H. and P. Davies, F. and E. Gibbs, Lenox and Jasper), although Berger had also observed them but considered them artifacts. The discovery of electroencephalography was a milestone for the advancement of neuroscience and of neurologic and neurosurgical everyday practice, especially for patients with seizures. The real nature of the disease and its management (anticonvulsants, excision of brain scars, tumors, etc.) were unkonown at that time. Berger's persistent, hardworking and steady personal style overcame all technical and other obstacles during the experiments. Unfortunately, he gained neither acceptance nor recognition, among his fellow contemporaries from abroad. Political turmoils at the dawn of World War II, in the country of Nazi's ideology and finally the outbreak of war, along with the complete ban of any further work on EEG after his forced retirement, led him to an uneasy professional and personal end. In the era when lumbar puncture, pneumoencephalography and ventriculography were the only diagnostic tools to detect and localize "sick sites" in the brain, EEG revolutionized daily neurologic and neurosurgic procedures, and bridged a time period of about 40 years (1930-1970) until the advent of computer tomography. Nowadays its importance is not as great as it was before, but it still has its place in the diagnostic work-up of seizures, brain tumors, degenerative brain changes, and other diseases.

The neurologist and Harvard criteria for brain death

The Harvard ad hoc committee to examine the definition of brain death, chaired by anesthesiologist Beecher, published their report in 1968. Throughout the years, the committee has been a target of criticism. However, the workings of the ad hoc committee have not been carefully evaluated, and could provide insight into the role of the neurologists and their interaction with contemporaries. Review of the original files and interviews with three surviving members-Adams, Potter, and Murray-revealed 1) a major role and original contributions of the neurologists Schwab and Adams in defining criteria, and 2) a swift and decisive working committee that formulated a document aimed at simplicity and accuracy, and without special interest.

Mario Gozzano: the work of an EEG pioneer

The study of the early history of electroencephalography can yield fascinating insights and surprises. A revisit to the work of Mario Gozzano (1898-1986) has proved to be particularly stimulating. His EEG study of 1935 is a classic and should be resurrected from the graveyard of history. Gozzano was an eminent clinical neurologist-epileptologist and chairman of the neurological-psychiatric university departments in Cagliari, Pisa, Bologna and, from 1951 to his retirement, in Rome. He quickly recognized the significance of EEG and produced his major experimental EEG work in the wake of a stay at the Berlin-Buch Brain Institute. His prolonged corticograms of various regions in the rabbit demonstrated striking differences between various cortical areas. Topical cortical strychnine produced spikes (a barely known phenomenon at that time) and the evolution from interictal to ictal spiking. Spikes induced by visual stimuli may be regarded as precursors of evoked potentials. While Hans Berger was a holist ("the brain working as a whole"), Gozzano (influenced by Vogt and Kornmueller) provided EEG support for the localizationists.

[QEEG and brain mapping. Historial develoment, clinical practices and epistemological issues]

Although it has been more than two decades since brain mapping was introduced in medicine, its scientific value and clinical practice have not been proved. This paper makes an overview about the historical development of brain mapping, its usefulness in psychiatry and lays epistemological issues concerning the role of technology in medical settings. Both historical and technological development of qEEG gives us the opportunity to think about complexity between ethics, science, technology and medicine.

Clinical neurophysiology in Uppsala, 1967-2001

This is a review of the activities at the Department and Institution of Clinical Neurophysiology at Uppsala University Hospital from 1967 to 2001. The most important routine clinical methods are briefly described, and a summary of some of the research projects is given.

[From historical EEG to signal treatment: applications in childhood epilepsy]

Electroencephalography is a fundamental investigation for the characterization of an epilepsy. It remains a unique way for the evaluation of a cortical activity in real time. The classification of epileptic syndromes is based on electroclinical correlations. The characterization of EEG abnormalities is essential for establishing a specific syndromic diagnosis. Discussing the historical evolution of EEG techniques we show how the recent development of numerized EEG provided the medical community with very useful and simple tools for the treatment of EEG signals. These tools are now integrated in everyday clinical practice. Several methods are presented, illustrating potential applications in childhood epilepsies.

Sleep deprivation in the rat: X. Integration and discussion of the findings. 1989

The results of a series of studies on total and selective sleep deprivation in the rat are integrated and discussed. These studies showed that total sleep deprivation, paradoxical sleep deprivation, and disruption and/or deprivation of non-rapid eye movement (NREM) sleep produced a reliable syndrome that included death, debilitated appearance, skin lesions, increased food intake, weight loss, increased energy expenditure, decreased body temperature during the late stages of deprivation, increased plasma norepinephrine, and decreased plasma thyroxine. The significance of this syndrome for the function of sleep is not entirely clear, but several changes suggested that sleep may be necessary for effective thermoregulation.

The tortoise and the love-machine: Grey Walter and the politics of electroencephalography

The life of the pioneer electroencephalographer, William Grey Walter, initially appears to be a paradigmatic example of the process of network building and delegation identified by Michel Callon and Bruno Latour. In his professional career, Walter continually repositioned himself, moving from an unhappy beginning as an expert in the apparently unless and suspect technology of the EEG, to become a self-styled crucial mediator in subjects as diverse as medical diagnosis, forensic detection, marriage counseling, and international diplomacy. This position was achieved moreover through the construction and co-option of human and mechanical accomplices - laboratory assistants, electrical tortoises, and mechanical analyzers - which sustained his research and propagated his arguments. However in contrast to Callon and Latour's atomistic account of scientific power and agency, this paper will extend their analysis to explore the impact of network building and delegation on domestic life, human desire, and personal identity. Walter's engagement with the complexities of love and the human brain demonstrates how the transformative power of scientific rhetoric extends simultaneously into both the organization of the world and the subjectivity of the individual.

The golden age of rapid eye movement sleep discoveries. 1. Lucretius--1964

Although there were several premonitory signs of a sleep stage with dreaming, it was only in 1953 that such a stage was identified with certainty. This paper analyses the observations and research related to this dreaming stage (rapid eye movement sleep) until 1964. During these 11 years of research, the main psychological and physiological characteristics of this sleep stage were first described. Where the few results or discussions were later questioned, today's current state of knowledge is briefly outlined.