Pharmaco-EEG, Pharmaco-Sleep and EEG-Based Personalized Medicine

Electrophysiological brain research has a long tradition going back as far as 1875 when the first report of the animal electroencephalogram (EEG) was published by Caton [1]. The first recordings from the human skull were reported by Berger [2] in the late 1920s and, not long thereafter, the intriguing world of the effects of drugs on the EEG opened up a scientific area of research known today as pharmaco-EEG. In 1957, Roth and colleagues reported EEG findings associated with a favourable treatment outcome to electroconvulsive therapy (ECT), laying the foundation of what we now consider as EEG-based personalized medicine [3]. The landscape significantly evolved with the advancement of computerized methods and the development of novel technologies for signal processing and quantification of the EEG and sleep polygraphy (polysomnography). More recently, during the last decade, many successful endeavours have improved the understanding and the sophisticated analysis of the electrophysiological brain as a three-dimensional organ.
In essence, pharmaco-EEG deals with the description and quantitative analysis of the effects of substances on the central nervous system (CNS) by means of neurophysiological and electrophysiological methods used within the framework of clinical and experimental pharmacology, neurotoxicology, therapeutic research and associated disciplines. Processing the EEG signals reveals the spontaneous synchronized postsynaptic neuronal activity of the cortex with high temporal resolution, thus providing a more direct measure of brain function than the haemodynamic or metabolic measures assessed by imaging techniques such as fMRI or FDG-PET. EEG is also unique in its direct applicability in both humans and animals. In totality, pharmaco-EEG encompasses a number of non-invasive methods that can be used routinely to assess the effects of pharmacological compounds on the CNS. Pharmaco-EEG can thus help further understanding of brain dynamics or pathology and can support (e.g. as a biomarker) the discovery, development and targeted application of drugs to treat CNS disorders.
The articles included in this issue of Neuropsychobiology are presented by the International Pharmaco-EEG Society (IPEG) to provide an overview of the techniques used in pharmaco-EEG, pharmaco-sleep and EEG-based personalized medicine research. Various aspects of pharmaco-EEG are covered, including EEG studies in animals with their translational applications (Jobert et al. [4,5]), advanced analysis of pharmaco-EEG in humans (Jobert and Wilson [6]) and pharmaco-sleep in humans (Anderer [7]). Further, the potential role of pharmaco-EEG and pharmaco-sleep for early decision-making in drug development and for the purpose of identifying whether compounds are active in the CNS is discussed (Jobert et al. [8]). The key outputs in this application are pharmacodynamic measures of the effects of centrally acting compounds. Additional theoretical aspects are discussed by Sander et al. [9], who demonstrate that detailed assessment of wakefulness and vigilance regulation offers a very exciting prospect in pharmaco-EEG research.