Browsing by Subject "Auditory cortex"

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    Intrinsic oscillations of auditory networks in schizophrenia and bipolar disorder
    (Yerküre Tanıtım ve Yayıncılık Hizmetleri A. Ş., 2019) Atagün, M. İ.; Akın, B.; Algın, Oktay; Sıkoğlu, E. M.; Can, S. S.; Kaymak, S. U.; Çayköylü, A.; Moore, C.; Phillips, M.; Ongur, D.
    Objective: Several types of evidence have shown that auditory networks are dysfunctional in schizophrenia (Sch) and bipolar disorders (BD). Auditory cortices show abnormalities in hallucinations or during remission. This study aimed to assess resting-state connectivity of auditory cortices in Sch and BD. Method: Patients with BD-1 (n=28), BD-2 (n=21), Sch (n=30), and healthy controls (HC, n=30) were enrolled into the study. A 3 Tesla whole-body magnetic resonance imaging (MRI) system with a 32-channel phase-array head coil was used to acquire the MRI data. T1-weighted anatomical and gradient-echo based Echoplanar Imaging sequences were used. MATLAB and Freesurfer software packages were used for data analyses. Connectivity alterations within the auditory network guided our further seedbased connectivity analysis. Results: The left angular gyrus volume was decreased in Sch and BD-2 groups. The supramarginal gyrus had hyperconnectivity with the medial prefrontal cortices and decreased connectivity with the medial superior temporal gyrus (STG) in the BD-1 and BD-2 groups. The left superior temporal sulcus (STS) had increased connectivity with the bilateral posterior cingulate cortex in BD-1 and BD-2 and increased connectivity with the dorsal prefrontal cortices in the Sch group. The STS had increased connectivity with the medial STG in the BD-1 and Sch groups, whereas connectivity decreased in the BD-2 group. Conclusion: These findings suggest that functional connectivity of resting-state networks are altered in BD and Sch. Auditory network alterations may predispose to dysfunctional auditory information processing. Further studies are needed to determine the relationship between symptoms and auditory network dysfunction.
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    Perisylvian GABA levels in schizophrenia and bipolar disorder
    (Elsevier Ireland Ltd, 2017) Atagün, M. İ.; Şıkoglu, M. E.; Soykan, Ç.; Can, S. S.; Ulusoy-Kaymak S.; Çayköylü, A.; Algın O.; Phillips, M. L.; Öngür, D.; Moore, C. M.
    The aim of this study is to measure GABA levels of perisylvian cortices in schizophrenia and bipolar disorder patients, using proton magnetic resonance spectroscopy (1H-MRS). Patients with schizophrenia (n = 25), bipolar I disorder (BD-I; n = 28) and bipolar II disorder (BD-II; n = 20) were compared with healthy controls (n = 30).1H-MRS data was acquired using a Siemens 3 T whole body scanner to quantify right and left perisylvian structures’ (including superior temporal lobes) GABA levels. Right perisylvian GABA values differed significantly between groups [χ2= 9.62, df: 3, p = 0.022]. GABA levels were significantly higher in the schizophrenia group compared with the healthy control group (p = 0.002). Furthermore, Chlorpromazine equivalent doses of antipsychotics correlated with right hemisphere GABA levels (r2= 0.68, p = 0.006, n = 33). GABA levels are elevated in the right hemisphere in patients with schizophrenia in comparison to bipolar disorder and healthy controls. The balance between excitatory and inhibitory controls over the cortical circuits may have direct relationship with GABAergic functions in auditory cortices. In addition, GABA levels may be altered by brain regions of interest, psychotropic medications, and clinical stage in schizophrenia and bipolar disorder. � 2016 Elsevier Ireland Ltd