Akademik Merkezler / Academic Centers
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Browsing Akademik Merkezler / Academic Centers by Publisher "Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA"
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Publication Open Access Beta Oscillatory Responses in Healthy Subjects and Subjects with Mild Cognitive Impairment Upon Application of Stimuli with Cognitive Load(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2013-05-01) Güntekin, Bahar; Emek, Derya Durusu; Yener, Görsev; Kurt, Pınar; BAŞAR, EROL; 142226; 204666; 227002; 143760; 24351The aim of the present study was to investigate the role of beta oscillatory responses upon cognitive load in healthy subjects and in subjects with mild cognitive impairment (MCI). The role of beta oscillations upon cognitive stimulation is least studied in comparison to other frequency bands. The study included 17 consecutive patients with MCI (mean age = 70.8 ± 5.6 years) according to Petersen's criteria, and 17 age- and education-matched normal elderly controls (mean age = 68.5 ± 5.5 years). The experiments used a visual oddball paradigm. EEG was recorded at 30 cortical locations. EEG-evoked power, inter-trial phase synchronization, and event-related beta responses filtered in 15–20 Hz were obtained in response to target and non-target stimuli for both groups of subjects. In healthy subjects, EEG-evoked beta power, inter-trial phase synchronization of beta responses and event-related filtered beta responses were significantly higher in responses to target than non-target stimuli (p < 0.05). In MCI patients, there were no differences in evoked beta power between target and non-target stimuli. Furthermore, upon presentation of visual oddball paradigm, occipital electrodes depict higher beta response in comparison to other electrode sites. The increased beta response upon presentation of target stimuli in healthy subjects implies that beta oscillations could shift the system to an attention state, and had important function in cognitive activity. This may, in future, open the way to consider beta activity as an important operator in brain cognitive processes.Publication Metadata only Combined evaluation of oscillatory responses and memory performance in Bipolar disorder(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2009-04-15) Özerdem, Ayşegül; Akdede, Berna Binnur; Oğuz, Meral; Tunca, Zeliha; BAŞAR, EROL; 140995; 137693; 143327; 142226Publication Metadata only Decrease of Auditory Event Related Delta Oscillatory Responses in Patients with Alzheimer Type of Dementia(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2011-05-01) Yener, Görsev G.; Güntekin, Bahar; Necioğlu, Dilek; Tülay, Elif; BAŞAR, EROL; 143760; 204666; 142226Publication Metadata only Decrease of Event Related Delta Oscillations in Euthymic Patients with Bipolar Disorder(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2013-05-01) Atagün, Murat İlhan; Güntekin, Bahar; Masali, Belinda; Tülay, Emine Elif; BAŞAR, EROL; 142226; 25145; 204666; 142311Decreased delta oscillation upon cognitive load is common in patients with Alzheimer׳s disease, mild cognitive impairment, and schizophrenia. However, there is no previous study analyzing the delta responses in euthymic medication-free patients with bipolar disorder. Participants comprised of 22 euthymic medication-free patients with DSM-IV diagnoses of bipolar disorder and 21 healthy controls who were matched to the patients for sex, age, and education. Electroencephalographic activity was recorded at 30 electrode sites using an application of an auditory oddball paradigm. The maximum peak-to-peak amplitudes for each subject׳s averaged delta response (0.5-3.5Hz) were measured. There was a significant inter-group difference in evoked and event-related delta (0.5-3.5Hz) responses. Post-hoc comparisons revealed that the event-related delta oscillatory responses of the bipolar patient group were significantly lower than those of the healthy control group over the temporo-parietal and occipital electrode sites. Euthymic bipolar patients showed reduced event-related delta oscillatory responses in comparison to healthy subjects under cognitive load. The decrease of delta oscillations may be a common phenomenon that can be observed in different neuropsychiatric disorders with cognitive dysfunction.Publication Metadata only Decrease of event related theta coherence at left frontal-parietal connection in Alzheimer patients(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2008-04-01) Güntekin, Bahar; Yener, Görsev G.; Saatçı, Ertuğrul; BAŞAR, EROL; 142226; 204666; 143760; 10488Publication Metadata only Decrease of Long Distance Gamma (28-48 Hz) Coherence in Euthymic Drug Free Bipolar Patients upon Cognitive Load(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2010-05-01) Özerdem, Ayşegül; Güntekin, Bahar; Atagün, Murat İlhan; Turp, Bilge; Oral, Esat Timuçin; BAŞAR, EROL; 140995; 204666; 25145; 22231; 142226Publication Metadata only Decreased Evoked Right Fronto-Temporal Gamma Coherence in Acute Mania Improves After Valproate Monotherapy(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2009-04-15) Özerdem, Ayşegül; Güntekin, Bahar; Saatçı, Ertuğrul; BAŞAR, EROL; 140995; 204666; 10488; 142226Publication Metadata only Eeg event related coherence during affective picture viewing(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2015-05-01) Güntekin, Bahar; Femir, Banu; Turp Gölbaşı, Bilge; Tülay, Elif; BAŞAR, EROL; 204666; 142226Publication Metadata only Effect of valproate on oscillatory delta frequency responses to visual stimuli in a group of euthymic bipolar patients in comparison to healthy controls(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2007-04-15) Özerdem, Ayşegül; Kocaaslan, Sibel; Tunca, Zeliha; BAŞAR, EROL; 140995; 12868; 143327; 142226Publication Metadata only Event Related Coherence of Healthy Subjects upon Application of an Auditory Oddball Paradigm(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2010-05-01) Güntekin, Bahar; BAŞAR, EROL; 142226; 204666Publication 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 during recognition of face expressions(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2008-04-01) Güntekin, Bahar; BAŞAR, EROL; 142226; 204666Publication Metadata only Evoked and Event Related Theta Oscillations are Decreased in Drug-Free Euthymic Bipolar Patients(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2011-05-01) Atagün, Murat İlhan; Özerdem, Ayşegül; Güntekin, Bahar; BAŞAR, EROL; 25145; 140995; 204666; Erol Başar 142226Publication Metadata only Evoked Coherence in Alzheimer Patients Upon Application of Basic Visual Paradigm(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2009-04-15) Güntekin, Bahar; Yener, Görsev G.; BAŞAR, EROL; 142226; 204666; 143760Publication Metadata only Evolution of alpha activity and intuitive behaviour(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2007-04-15) Güntekin, Bahar; BAŞAR, EROL; 142226; 204666Publication Metadata only Gender differences in recognition of facial expressions: Occipital beta oscillations of female subjects depict higher amplitudes(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2007-04-15) Güntekin, Bahar; BAŞAR, EROL; 204666; 142226Publication Metadata only High occipital beta (18-30 Hz) and low occipital alpha (8-13 Hz) oscillatory response to target visual stimuli in bipolar disorder reduce with chronic valproate use(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2008-04-01) Özerdem, Ayşegül; Güntekin, Bahar; Tunca, Zeliha; BAŞAR, EROL; 140995; 204666; 143327; 142226Publication Metadata only Increase of Beta Response upon Application of Lithium in Euthymic Bipolar Patients(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2011-05-01) Tan, Devran; Özerdem, Ayşegül; Güntekin, Bahar; Atagün, Murat İlhan; Tülay, Elif; Karadağ, Figen; BAŞAR, EROL; 103606; 140995; 204666; 25145; 111061; Erol Başar 142226Publication Open Access Occipital sources of resting-state alpha rhythms are related to local gray matter density in subjects with amnesic mild cognitive impairment and Alzheimer's disease(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2015-02) Yener, Görsev; Emek Savaş, Derya Durusu; Babiloni, Claudio; Del Percio, Claudio; Boccardi, Marin; Lizio, Roberta; Lopez, Susanna; Carducci, Filippo; Marzano, Nicola; Soricelli, Andrea; Ferri, Raffaele; Triggiani, Antonio Ivano; Prestia, Annapaola; Salinari, Serenella; Rasser, Paul E.; Fama, Francesco; Nobili, Flavio; Gesualdo, Loreto; Mundi, Ciro; Thompson, Paul M.; Rossini, Paolo M.; Frisoni, Giovanni B.; BAŞAR, EROL; 142226Occipital sources of resting-state electroencephalographic (EEG) alpha rhythms are abnormal, at the group level, in patients with amnesic mild cognitive impairment (MCI) and Alzheimer's disease (AD). Here, we evaluated the hypothesis that amplitude of these occipital sources is related to neuro-degeneration in occipital lobe as measured by magnetic resonance imaging. Resting-state eyes-closed EEG rhythms were recorded in 45 healthy elderly (Nold), 100 MCI, and 90 AD subjects. Neuro-degeneration of occipital lobe was indexed by weighted averages of gray matter density, estimated from structural MRIs. EEG rhythms of interest were alpha 1 (8-10.5 Hz) and alpha 2 (10.5-13 Hz). EEG cortical sources were estimated by low-resolution brain electromagnetic tomography. Results showed a positive correlation between occipital gray matter density and amplitude of occipital alpha 1 sources in Nold, MCI, and AD subjects as a whole group (r = 0.3, p = 0.000004, N = 235). Furthermore, there was a positive correlation between the amplitude of occipital alpha 1 sources and cognitive status as revealed by Mini Mental State Examination score across all subjects (r = 0.38, p = 0.000001, N = 235). Finally, amplitude of occipital alpha 1 sources allowed a moderate classification of individual Nold and AD subjects (sensitivity: 87.8%; specificity: 66.7%; area under the receiver operating characteristic curve: 0.81). These results suggest that the amplitude of occipital sources of resting- state alpha rhythms is related to AD neurodegeneration in occipital lobe along pathologic aging. (C) 2015 Elsevier Inc. All rights reserved.Publication Metadata only Significant Reduction of EEG Alpha Activity and Sensory Alpha Response in Bipolar Patients(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2010-05-01) Güntekin, Bahar; Atagün, Murat İlhan; Özerdem, Ayşegül; BAŞAR, EROL; 142226; 204666; 25145; 140995