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Yayın Auditory Event-Related Delta Oscillatory Responses are Reduced in Patients with Mild Cognitive Impairment(ELSEVIER SCIENCE INC, 2012) Kurt, Pinar; Emek, Derya Durusu; Batum, Kubra; Golbasi, Bilge Turp; Guntekin, Bahar; Karsidag, Sibel; Basar, Erol; Yener, Gorsev…Yayın Increase of Beta Response upon Application of Lithium in Euthymic Bipolar Patients(ELSEVIER SCIENCE INC, 2011) Tan, Devran; Ozerdem, Aysegul; Guntekin, Bahar; Atagun, Ilhan; Tulay, Elif; Karadag, Figen; Basar, Erol…Yayın Increased Beta Frequency (15-30 Hz) Oscillatory Responses in Euthymic Bipolar Patients Under Lithium Monotherapy(SAGE PUBLICATIONS INC, 2016) Tan, Devran; Ozerdem, Aysegul; Guntekin, Bahar; Atagun, M. Ilhan; Tulay, Elif; Karadag, Figen; Basar, ErolThe 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.Yayın Lithium Excessively Enhances Alpha and Beta Oscillatory Responses in Bipolar Disorder(ELSEVIER SCIENCE INC, 2013) Ataguen, Murat I.; Guntekin, Bahar; Tan, Devran; Tulay, Elif; Basar, Erol…Yayın Lithium excessively enhances event related beta oscillations in patients with bipolar disorder(ELSEVIER SCIENCE BV, 2015) Atagun, Murat Ilhan; Guntekin, Bahar; Tan, Devran; Tulay, Emine Elif; Basar, ErolBackground: Previous resting-state electroencephalography studies have consistently shown that lithium enhances delta and theta oscillations in default mode networks. Cognitive task based networks differ horn resting-state networks and this is the first study to investigate effects or 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), laterality X group (p=0.043) and stimulus X location (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. (C) 2014 Elsevier B.V. All rights reserved.Yayın Patients with Mild Cognitive Impairment Display Reduced Auditory Event-Related Delta Oscillatory Responses(HINDAWI PUBLISHING CORPORATION, 2014) Kurt, Pinar; Emek-Savas, Derya Durusu; Batum, Kubra; Turp, Bilge; Guntekin, Bahar; Karsidag, Sibel; Yener, Gorsev GulmenBackground. Event-related oscillations (ERO) may provide a useful tool for the identification of cognitive deficits in mild cognitive impairment (MCI) and Alzheimer's disease (AD). In the present study, we investigate peak-to-peak amplitude of auditory eventrelated delta oscillations of MCI subjects. Method. The study included twenty-two consecutive patients with MCI recruited in neurology clinic and 21 age-and education-matched normal elderly controls. A classical auditory oddball paradigm was used in the experiments. EEG was recorded from F-3, F-z, F-4, C-3, C-z, C-4, P-3, P-z, P-4, O-1, O-z, and O-2 locations. The maximum peak-to-peak amplitudes for each subject's averaged delta response (0.5-2.2Hz) weremeasured. Results. The amplitudes between groups differed significantly at the frontal and mid-centroparietal locations. ANOVA on delta responses revealed a significant effect for groups (F-(1.41) = 4.84, P = 0.033), indicating a larger delta response for healthy controls thanMCI subjects. Post hoc comparisons revealed that peak-to-peak delta response was significantly larger for healthy controls than for MCI over electrode sites F-3, F-z, F-4, C-z, C-4, and Pz. Discussion. Event-related delta frequency band seems to be the most affected oscillatory response in cognitive impairment due to AD. Therefore, it deserves to be investigated as a candidate electrophysiological biomarker in further studies.
