BeyinMer / Beyin Dinamiği Araştırma Merkezi
Permanent URI for this collectionhttps://hdl.handle.net/11413/6773
BeyinMer / Beyin Dinamiği Araştırma Merkezi / Brain Dynamics Research Center
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Browsing BeyinMer / Beyin Dinamiği Araştırma Merkezi by Author "Başar Eroğlu, Canan"
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Publication Open Access Best method for analysis of brain oscillations in healthy subjects and neuropsychiatric diseases(Elsevier Science Bv, Po Box 211, 1000 AE Amsterdam, Netherlands, 2016-05) Turp Gölbaşı, Bilge; Tülay, Elif; Aydın, Serap; Başar Eroğlu, Canan; BAŞAR, EROL; 142226; 17772The research related to brain oscillations and their connectivity is in a new take-off trend including the applications in neuropsychiatric diseases. What is the best strategy to learn about functional correlation of oscillations? In this report, we emphasize combined application of several analytical methods as power spectra, adaptive filtering of Event Related Potentials, inter-trial coherence and spatial coherence. These combined analysis procedure gives the most profound approach to understanding of EEG responses. Examples from healthy subjects, Alzheimer's Diseases, schizophrenia, and Bipolar Disorder are described. (C) 2016 The Authors. Published by Elsevier B.V.Publication Metadata only Brain Oscillations Evoked by the Face of a Loved Person(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2008-06-12) Schmiedt-Fehr, Christina; Öniz, Adile; Başar Eroğlu, Canan; BAŞAR, EROL; TR59951; TR142226Previous studies have shown a close interrelation between emotional processing and memory processes using facial stimuli and applying the concept of oscillatory brain dynamics. Amending prior findings the influence of neural correlates related to the emotional state termed "romantic love" was investigated. Specifically, the effect of feelings of love on face perception was of interest. Pictures of a "loved person" were presented to female subjects and the elicited responses were compared with responses to pictures showing faces of a "known and appreciated person" or an "unknown person" during EEG recordings (n=20 females). As a control condition light stimulation was employed. The sequence of faces shown was presented in random and block-design. EEG data was analyzed considering maximum amplitudes and topographical differences within the conventional frequency bands of delta, theta, alpha, beta and gamma. Differences between light and face stimuli were found in the delta and theta bands and differences between the face types and the two designs were found in the delta band. The delta response to the picture of the "loved person" showed significantly higher amplitude values, not only in comparison with the "unknown person", but also with the picture of the "appreciated person". Frontal lobes appear to react to different types of facial stimuli with specific increases in delta responses. The difference between the response to the "loved person" and of the "known and appreciated person" reflects the component of the emotion denoted as love. The findings and their interpretations are discussed within the framework of event-related oscillations and complex stimulus processing emphasizing the concept of dynamic localization. (C) 2008 Published by Elsevier B.V.Publication Metadata only Brain's Alpha, Beta, Gamma, delta, and theta oscillations in neuropsychiatric diseases: Proposal for biomarker strategies(2013) Başar Eroğlu, Canan; Güntekin, Bahar; Gülmen Yener, Görsev; BAŞAR, EROLBrain oscillations have gained tremendous importance in neuroscience during recent decades as functional building blocks of sensory-cognitive processes. Research also shows that event-related oscillations (EROs) in "alpha," "beta," "gamma," "delta," and "theta" frequency windows are highly modified in pathological brains, especially in patients with cognitive impairment. The strategies and methods applied in the present report reflect the innate organization of the brain: "the whole brain work." The present paper is an account of methods such as evoked/event-related spectra, evoked/ERDs, coherence analysis, and phase-locking. The report does not aim to cover all strategies related to the systems theory applied in brain research literature. However, the essential methods and concepts are applied in several examples from Alzheimer's disease (AD), schizophrenia, and bipolar disorder (BD), and such examples lead to fundamental statements in the search for neurophysiological biomarkers in cognitive impairment. An overview of the results clearly demonstrates that it is obligatory to apply the method of oscillations in multiple electroencephalogram frequency windows in search of functional biomarkers and to detect the effects of drug applications. Again, according to the summary of results in AD patients and BD patients, multiple oscillations and selectively distributed recordings must be analyzed and should include multiple locations. Selective connectivity between selectively distributed neural networks has to be computed by means of spatial coherence. Therefore, by designing a strategy for diagnostics, the differential diagnostics, and application of (preventive) drugs, neurophysiological information should be analyzed within a framework including multiple methods and multiple frequency bands. The application of drugs/neurotransmitters gains a new impact with the analysis of oscillations and coherences. A more clear and differentiated analysis of drug effects can be attained in comparison to the application of the conventional wide-band evoked potential and event-related potential applications.Publication Metadata only Event related oscillations differentiate the face of the loved person from other faces(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2008-04-01) Schmiedt-Fehr, Christina; Öniz, Adile; Başar Eroğlu, Canan; BAŞAR, EROL; 142226; 59951Publication Metadata only Event related oscillations triggered by the face of the loved person(Elsevier Science Bv, Po Box 211, 1000 AE Amsterdam, Netherlands, 2008-09) Schmiedt Fehr, C.; Öniz, Adile; Başar Eroğlu, Canan; BAŞAR, EROL; 142226; 59951Publication Metadata only Mindful brain and EEG-neurophysiology Preface(Elsevier Science Bv, Po Box 211, 1000 AE Amsterdam, Netherlands, 2016-05) Güntekin, Bahar; Yener, Görsev G.; Başar Eroğlu, Canan; BAŞAR, EROL; 142226; 204666; 143760Publication Metadata only Selective Gamma Activation in Alzheimer, Bipolar Disease and Schizophrenia(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 Usa, 2011-05-01) Başar Eroğlu, Canan; Güntekin, Bahar; Özerdem, Ayşegül; Yener, Görsev; BAŞAR, EROL; 142226; 274866; 204666; 140995; 143760Publication Open Access What does the broken brain say to the neuroscientist? Oscillations and connectivity in schizophrenia, Alzheimer's disease, and bipolar disorder(Elsevier Science Bv, Po Box 211, 1000 AE Amsterdam, Netherlands, 2016-05) Mathes, Birgit; Schmiedt-Fehr, Christina; Femir, Banu; Emek Savaş, Derya Durusu; Tülay, Elif; Tan, Devran; Düzgün, Aysel; Güntekin, Bahar; Özerdem, Ayşegül; Yener, Görsev G.; Başar Eroğlu, Canan; BAŞAR, EROL; 142226; 103606; 204666; 140995; 143760The application of the concept and methods of brain oscillations has been an important research area in neurosciences. In the last decades, besides the application in cognitive processes, the study of changes in brain oscillations in diseases has also become an important focal point of research. In the present paper, some remarkable examples in three different diseases are taken into consideration: 1) schizophrenia (SZ), 2) Alzheimer's disease (AD), 3) bipolar disorders (BD). In the current literature, decreased oscillations in cortical recordings are observed in most of the pathologies. For example, decrease of gamma activity in SZ, decrease of delta activity in almost all diseases, as well as frequency shifts in alpha and the lower frequencies were recorded. However, there are also paradoxical cases in which an increase of oscillatory activities is observed. In BD, whereas alpha activity is greatly decreased, a huge increase of beta activity is observed. Or, in SZ, a paradoxical increase of gamma activity can be observed during cognitive loading. We also observed paradoxical changes in the analysis of connectivity. In AD, we find that alpha, delta, and theta coherences between distant parts of the cortex are greatly decreased, whereas in the gamma band, event-related coherences attain very high values. The comparison of the results and paradoxical changes in diseases may lead to important conclusions related to the web of oscillations and neurotransmitters. In turn, we could gain new insights to approach "brain function", in general. (C) 2016 The Authors. Published by Elsevier B.V.