Current Trends in Neurosciences, Nurcan Orhan,Zeynep Karakaş,Tamer Demiralp, Editör, Istanbul University Press, İstanbul, ss.249-267, 2024
CURRENT TRENDS IN NEUROSCIENCES CHAPTER 9 ELECTROENCEPHALOGRAPHIC INVESTIGATION OF BRAIN FUNCTIONS Sevcan AYAŞ-KÖKSAL1, Emine Elif TÜLAY2, Banu FEMİR-GÜRTUNA3, Mesut CANLI4, Nuh YILMAZ5, Zeliha MATUR6, Tamer DEMİRALP7 1PhD, Istanbul University, Institute of Graduate Studies in Health Sciences, Advanced Neurological Sciences PhD Program, Istanbul, Türkiye E-mail: sevcanayas@gmail.com 2PhD, Muğla Sıtkı Koçman University, Faculty of Engineering, Department of Software Engineering, Muğla, Türkiye E-mail: eliftulay@mu.edu.tr 3PhD, MEF University, Department of Psychology, Istanbul, Türkiye E-mail: femirb@mef.edu.tr 4MD, Istanbul University, Faculty of Medicine, Department of Physiology, Istanbul, Türkiye E-mail: mesut.canli@istanbul.edu.tr 5MD, Istanbul University, Faculty of Medicine, Department of Physiology, Istanbul, Türkiye E-mail: nuh.yilmaz@istanbul.edu.tr 6Professor, Bezmialem Vakıf University, Faculty of Medicine, Department of Neurology, Istanbul, Türkiye E-mail: zmatur@bezmialem.edu.tr 7Professor, Istanbul University, Faculty of Medicine, Department of Physiology, Istanbul, Türkiye E-mail: demiralp@istanbul.edu.tr DOI: 10.26650/B/LSB44.2024.037.009 ABSTRACT Electroencephalogram (EEG) as a non-invasive method of measuring brain’s electrical activity has been widely used for investigating many neuroscientific and clinical questions. Generated mainly by the post-synaptic potentials on the apical dendrites of the cortical pyramidal neurons, it represents the synchronized inputs from a wide variety of local and/or distant sources to the main output cells of the cortex and reflects the neuronal activity with a high temporal resolution. Despite the poor spatial resolution and ill-defined inverse problem of estimating the generator locations, the high temporal resolution of the EEG signal allows for precisely detecting transient brain signals such as epileptic spikes or event-related potentials (ERP) as well as for precisely characterizing the neural synchronization patterns in specific 250 ELECTROENCEPHALOGRAPHIC INVESTIGATION OF BRAIN FUNCTIONS frequency bands. While the analysis of the ongoing EEG is based on the statistical characterization of rhythmic components, event-related EEG signals temporally associated with specific sensory, motor, or cognitive events, can be characterized both as transient ERP wave components in time-domain or as event-related oscillations (ERO) in the frequency domain. Such EEG analyses have provided important information about the functional organization of the healthy brain. Additionally, beyond the fundamental clinical use of the EEG in the diagnosis of the epilepsy, the ERPs and EROs allowed for a range of further clinical investigations on the neural mechanisms of various neuropsychiatric disorders. This chapter will present basic concepts, measurement and analysis methods of the EEG, and an overview with few sample studies for the use of the EEG for basic neuroscientific and clinical questions. Keywords: Ongoing EEG, event-related potentials, event-related oscillations, cognition