Person: BAŞAR, EROL
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BAŞAR
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EROL
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Publication Metadata only Event Related Beta and Gamma Oscillations in Perception of Affective Pictures(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 Usa, 2014-05-01) Güntekin, Bahar; Tülay, Elif; Turp Gölbaşı, Bilge; BAŞAR, EROL; 204666; 142226Publication Metadata only Affective pictures processing is reflected by an increased long-distance EEG connectivity(Springer, Van Godewijckstraat 30, 3311 Gz Dordrecht, Netherlands, 2017-08) Güntekin, Bahar; Femir, Banu; Turp Gölbaşı, Bilge; Tülay, Elif; BAŞAR, EROL; 204666; 142226Analysis of affective picture processing by means of EEG has invaded the literature. The methodology of event-related EEG coherence is one of the essential methods used to analyze functional connectivity. The aims of the present study are to find out the long range EEG connectivity changes in perception of different affective pictures and analyze gender differences in these long range connected networks. EEGs of 28 healthy subjects (14 female) were recorded at 32 locations. The participants passively viewed emotional pictures (IAPS, unpleasant, pleasant, neutral). The long-distance intra-hemispheric event-related coherence was analyzed for delta (1-3.5 Hz), theta (4-7.5 Hz), and alpha (8-13 Hz) frequency ranges for F-3-T-7, F-4-T-8, F-3-TP7, F-4-TP8, F-3-P-3, F-4-P-4, F-3-O-1, F-4-O-2, C-3-O-1, C-4-O-2 electrode pairs. Unpleasant pictures elicited significantly higher delta coherence values than neutral pictures (p < 0.05), over fronto-parietal, fronto-occipital, and centro-occipital electrode pairs. Furthermore, unpleasant pictures elicited higher theta coherence values than pleasant (p < 0.05) and neutral pictures (p < 0.05). The present study showed that female subjects had higher delta (p < 0.05) and theta (p < 0.05) coherence values than male subjects. This difference was observed more for emotional pictures than for neutral pictures. This study showed that the brain connectivity was higher during emotional pictures than neutral pictures. Females had higher connectivity between different parts of the brain than males during emotional processes. According to these results, we may comment that increased valence and arousal caused increased brain activity. It seems that not just single sources but functional networks were also activated during perception of emotional pictures.Publication Metadata only Lithium Excessively Enhances Alpha and Beta Oscillatory Responses in Bipolar Disorder(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 Usa, 2013) Atagün, Murat İlhan; Güntekin, Bahar; Tan, Devran; Tülay, Elif; BAŞAR, EROL; 25145; 204666; 103606; 142226Background: Previous resting-state electroencephalography studies have consistently shown that lithium enhances delta and theta oscillations in default mode networks. Cognitive task based networks differ from resting-state networks and this is the first study to investigate effects of lithium on evoked and event-related beta oscillatory responses of patients with bipolar disorder. Methods: The study included 16 euthymic patients with bipolar disorder on lithium monotherapy, 22 euthymic medication-free patients with bipolar disorder and 21 healthy participants. The maximum peak-to-peak amplitudes were measured for each subject's averaged beta responses (14-28 Hz) in the 0-300 ms time window. Auditory simple and oddball paradigm were presented to obtain evoked and event-related beta oscillatory responses. Results: There were significant differences in beta oscillatory responses between groups (p=0.010). Repeated measures ANOVA revealed location (p=0.007), lateralityXgroup (p=0.043) and stimulusXlocation (p=0.013) type effects. Serum lithium levels were correlated with beta responses. Limitations: The lithium group had higher number of previous episodes, suggesting that patients of the lithium were more severe cases than patients of the medication-free group. Discussion: Lithium stimulates neuroplastic cascades and beta oscillations become prominent during neuroplastic changes. Excessively enhanced beta oscillatory responses in the lithium-treated patients may be indicative of excessive activation of the neuron groups of the certain cognitive networks and dysfunctional GABAergic modulation during cognitive activity. Lithium Excessively Enhances Event Related Beta Oscillations in Patients with Bipolar Disorder | Request PDF. Available from: https://www.researchgate.net/publication/264897974_Lithium_Excessively_Enhances_Event_Related_Beta_Oscillations_in_Patients_with_Bipolar_Disorder [accessed Jul 12 2018].Publication 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 Brain's oscillatory responses in perception of emotional pictures(Elsevier Science Bv, Po Box 211, 1000 Ae Amsterdam, Netherlands, 2014-11) Güntekin, Bahar; Tülay, Elif; Turp Gölbaşı, Bilge; BAŞAR, EROL; 204666; 142226Publication Metadata only A comparative analysis of sensory visual evoked oscillations with visual cognitive event related oscillations in Alzheimer's disease(ELSEVIER IRELAND LTD, ELSEVIER HOUSE, BROOKVALE PLAZA, EAST PARK SHANNON, CO, CLARE, 00000, IRELAND, 2009-09-25) Yener, Görsev G.; Güntekin, Bahar; Tülay, Elif; BAŞAR, EROL; TR142226; TR142311; TR204666; TR143760We compared visual evoked oscillatory responses of subjects with Alzheimer's disease (AD) (n = 22) to healthy elderly controls (n = 19) elicited by simple light stimuli. The visual evoked oscillatory responses in AD subjects without cholinergic treatment (n = 11) show significant differences (df = 2.38. F = 4.957, P = 0.012) from the controls and the AD subjects treated with a cholinesterase inhibitor (n = 11). Higher theta oscillatory responses in untreated AD subjects are seen on the electrode locations over bi-parietal and right occipital regions after simple light stimuli with less, if any, cognitive load. These changes were restricted to the theta frequency range only and are related to location, frequency bands and drug effects. In our previous work we observed that visual event related oscillations elicited after the visual stimuli with a higher cognitive load, i.e. an oddball target, display lower amplitudes: between controls and AD subjects in delta frequency band without a drug effect, over the left and mid-central region. These differences between the visual evoked oscillations and the visual event related oscillations imply that there are at least two different cognitive circuits that are activated upon visual stimuli in AD patients. (c) 2009 Published by Elsevier Ireland Ltd.Publication Metadata only Increase of EEG functional connectivity during emotional picture processing(Wiley-Blackwell, 111 River St, Hoboken 07030-5774, Nj Usa, 2015-09) Güntekin, Bahar; Femir, Banu; Turp Gölbaşı, Bilge; Tülay, Elif; BAŞAR, EROL; 204666; 142226Publication Metadata only Increased Beta Frequency (15-30 Hz) Oscillatory Responses in Euthymic Bipolar Patients Under Lithium Monotherapy(Sage Publications Inc, 2455 Teller Rd, Thousand Oaks, Ca 91320 USA, 2016-04) Tan, Devran; Özerdem, Ayşegül; Güntekin, Bahar; Atagün, Murat İlhan; Tülay, Elif; Karadağ, Figen; BAŞAR, EROL; 103606; 140995; 204666; 25145; 111061; 142226The effect of lithium on neurocognition is not still fully explored. Brain oscillatory activity is altered in bipolar disorder. We aimed to assess the oscillatory responses of euthymic bipolar patients and how they are affected by lithium monotherapy. Event-related oscillations in response to visual target stimulus during an oddball paradigm in 16 euthymic drug-free and 13 euthymic lithium-treated bipolar patients were compared with 16 healthy controls. The maximum peak-to-peak amplitudes were measured for each subject's averaged beta (15-30 Hz) responses in the 0- to 300-ms time window over frontal (F3, Fz, F4), central (C3, Cz, C4), temporal (T7, T8), temporo-parietal (TP7, TP8), parietal (P3, Pz, P4), and occipital (O1, Oz, O2) areas. Patients under lithium monotherapy had significantly higher beta responses to visual target stimuli than healthy controls (P = .017) and drug-free patients (P = .015). The increase in beta response was observed at all electrode locations, however, the difference was statistically significant for the left (T7; P = .016) and right (T8; P = .031) temporal beta responses. Increased beta responses in drug-free patients and further significant increase in lithium-treated patients may be indicative of a core pathophysiological process of bipolar disorder and how it is affected by lithium. Whether the finding corresponds to lithium's corrective effect on the underlying pathology or to its neurocognitive side effect remains to be further explored. In either case, the finding is a sign that the oscillatory activity may be useful in tracking medication effect in bipolar disorder.Publication Metadata only Significant decrease of EEG alpha activity and visual-evoked alpha response in bipolar patients(Elsevier Science Bv, Po Box 211, 1000 AE Amsterdam, Netherlands, 2010-09) Güntekin, Bahar; Atagün, Murat İlhan; Tülay, Elif; Özerdem, Ayşegül; BAŞAR, EROL; Erol Başar 142226; 204666; 25145; 140995Publication Metadata only Visual sensory evoked oscillations in Alzheimer patients(Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA, 2009-04-15) Yener, Görsev G.; Güntekin, Bahar; Tülay, Elif; BAŞAR, EROL; 143760; 204666; 142226