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    Abnormal global signal topography of self modulates emotion dysregulation in major depressive disorder
    (Springernature, 2023) Keskin, Kaan; Eker, Mehmet Cagdas; Gonul, Ali Saffet; Northoff, Georg
    Major depressive disorder (MDD) is a complex mental disorder featured by an increased focus on the self and emotion dysregulation whose interaction remains unclear, though. At the same time, various studies observed abnormal representation of global fMRI brain activity in specifically those regions, e.g., cortical midline structure (CMS) in MDD that are associated with the self. Are the self and its impact on emotion regulation related to global brain activity unevenly represented in CMS relative to non-CMS? Addressing this yet open question is the main goal of our study. We here investigate post-acute treatment responder MDD and healthy controls in fMRI during an emotion task involving both attention and reappraisal of negative and neutral stimuli. We first demonstrate abnormal emotion regulation with increased negative emotion severity on the behavioral level. Next, focusing on a recently established three-layer topography of self, we show increased representation of global fMRI brain activity in specifically those regions mediating the mental (CMS) and exteroceptive (Right temporo-parietal junction and mPFC) self in post-acute MDD during the emotion task. Applying a complex statistical model, namely multinomial regression analyses, we show that increased global infra-slow neural activity in the regions of the mental and exteroceptive self modulates the behavioral measures of specifically negative emotion regulation (emotion attention and reappraisal/suppression). Together, we demonstrate increased representation of global brain activity in regions of the mental and exteroceptive self, including their modulation of negative emotion dysregulation in specifically the infra-slow frequency range (0.01 to 0.1 Hz) of post-acute MDD. These findings support the assumption that the global infra-slow neural basis of the increased self-focus in MDD may take on the role as basic disturbance in that it generates the abnormal regulation of negative emotions.
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    Altered hippocampal formation shape in first-episode depressed patients at 5-year follow-up
    (Pergamon-Elsevier Science Ltd, 2013) Isikli, Serhan; Ugurlu, Onur; Durmusoglu, Ece; Kizilates, Gozde; Kitis, Omer; Ozan, Erol; Eker, Cagdas; Coburn, Kerry; Gonul, Ali Saffet
    It is generally accepted that patients with major depressive disorder have smaller hippocampus size compared to healthy people. However, it is still not known if this situation exists before the onset of the disease or is a result of the toxic mechanism created by the depression itself. The findings of the long-term follow-up studies of first-episode depressed patients might contribute to solve the ongoing problem. In this study, the hippocampus of 18 first-episode patients who were followed-up for 5 years, were compared with those of healthy controls. There were no volumetric differences among groups neither at the baseline nor after 5 years of follow-up. However, shape analyses, using high dimensional mapping methods, revealed regional structural changes in the head and tail of the hippocampal formation in CA1 and subiculum regions in patients at the follow-up. Furthermore, a significant negative correlation was found with the number of days in depression without antidepressant treatment in the CA1 region in the head and tail of the hippocampal formation bilaterally. The findings of this study support the hypothesis that pathophysiological processes of depression induce structural alterations in depressed patients. (C) 2012 Elsevier Ltd. All rights reserved.
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    The Association Between Familial Risk and Brain Abnormalities Is Disease Specific: An ENIGMA-Relatives Study of Schizophrenia and Bipolar Disorder
    (Elsevier Science Inc, 2019) de Zwarte, Sonja M. C.; Brouwer, Rachel M.; Agartz, Ingrid; Alda, Martin; Aleman, Andre; Alpert, Kathryn I.; Bearden, Carrie E.; Bertolino, Alessandro; Bois, Catherine; Bonvino, Aurora; Bramon, Elvira; Buimer, Elizabeth E. L.; Cahn, Wiepke; Cannon, Dara M.; Cannon, Tyrone D.; Caseras, Xavier; Castro-Fornieles, Josefina; Chen, Qiang; Chung, Yoonho; De la Serna, Elena; Di Giorgio, Annabella; Doucet, Gaelle E.; Eker, Mehmet Cagdas; Erk, Susanne; Fears, Scott C.; Foley, Sonya F.; Frangou, Sophia; Frankland, Andrew; Fullerton, Janice M.; Glahn, David C.; Goghari, Vina M.; Goldman, Aaron L.; Gonul, Ali Saffet; Gruber, Oliver; de Haan, Lieuwe; Hajek, Tomas; Hawkins, Emma L.; Heinz, Andreas; Hillegers, Manon H. J.; Pol, Hilleke E. Hulshoff; Hultman, Christina M.; Ingvar, Martin; Johansson, Viktoria; Jonsson, Erik G.; Kane, Fergus; Kempton, Matthew J.; Koenis, Marinka M. G.; Kopecek, Miloslav; Krabbendam, Lydia; Kraemer, Bernd; Lawrie, Stephen M.; Lenroot, Rhoshel K.; Marcelis, Machteld; Marsman, Jan-Bernard C.; Mattay, Venkata S.; McDonald, Colm; Meyer-Lindenberg, Andreas; Michielse, Stijn; Mitchell, Philip B.; Moreno, Dolores; Murray, Robin M.; Mwangi, Benson; Najt, Pablo; Neilson, Emma; Newport, Jason; van Os, Jim; Overs, Bronwyn; Ozerdem, Aysegul; Picchioni, Marco M.; Richter, Anja; Roberts, Gloria; Aydogan, Aybala Saricicek; Schofield, Peter R.; Simsek, Fatma; Soares, Jair C.; Sugranyes, Gisela; Toulopoulou, Timothea; Tronchin, Giulia; Walter, Henrik; Wang, Lei; Weinberger, Daniel R.; Whalley, Heather C.; Yalin, Nefize; Andreassen, Ole A.; Ching, Christopher R. K.; van Erp, Theo G. M.; Turner, Jessica A.; Jahanshad, Neda; Thompson, Paul M.; Kahn, Rene S.; van Haren, Neeltje E. M.
    BACKGROUND: Schizophrenia and bipolar disorder share genetic liability, and some structural brain abnormalities are common to both conditions. First-degree relatives of patients with schizophrenia (FDRs-SZ) show similar brain abnormalities to patients, albeit with smaller effect sizes. Imaging findings in first-degree relatives of patients with bipolar disorder (FDRs-BD) have been inconsistent in the past, but recent studies report regionally greater volumes compared with control subjects. METHODS: We performed a meta-analysis of global and subcortical brain measures of 6008 individuals (1228 FDRs-SZ, 852 FDRs-BD, 2246 control subjects, 1016 patients with schizophrenia, 666 patients with bipolar disorder) from 34 schizophrenia and/or bipolar disorder family cohorts with standardized methods. Analyses were repeated with a correction for intracranial volume (ICV) and for the presence of any psychopathology in the relatives and control subjects. RESULTS: FDRs-BD had significantly larger ICV (d = +10.16, q < .05 corrected), whereas FDRs-SZ showed smaller thalamic volumes than control subjects (d = -0.12, q < .05 corrected). ICV explained the enlargements in the brain measures in FDRs-BD. In FDRs-SZ, after correction for ICV, total brain, cortical gray matter, cerebral white matter, cerebellar gray and white matter, and thalamus volumes were significantly smaller; the cortex was thinner (d < -0.09, q < .05 corrected); and third ventricle was larger (d = +0.15, q < .05 corrected). The findings were not explained by psychopathology in the relatives or control subjects. CONCLUSIONS: Despite shared genetic liability, FDRs-SZ and FDRs-BD show a differential pattern of structural brain abnormalities, specifically a divergent effect in ICV. This may imply that the neurodevelopmental trajectories leading to brain anomalies in schizophrenia or bipolar disorder are distinct.
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    Association of the brain-derived neurotrophic factor Val66Met polymorphism with hippocampus volumes in drug-free depressed patients
    (Taylor & Francis Ltd, 2011) Gonul, Ali Saffet; Kitis, Omer; Eker, M. Cagdas; Eker, Ozlem Donat; Ozan, Erol; Coburn, Kerry
    Objectives. Val66Met BDNF gene polymorphism is shown to affect the function of mature BDNF and mature BDNF plays an important role in the hippocampal neurogenesis and neuronal survival. Methods. A relationship of Val66Met BDNF gene polymorphism and hippocampal volumes in 33 MDD patients and 40 healthy controls is investigated. Region of interest analysis was conducted on the images acquired via MRI. Results. Depressed patients had smaller left hippocampal volumes compared to healthy controls. The diagnosis of MDD was not significantly related to hippocampal volumes among Met carriers; however, among Val homozygotes depressed patients had significantly smaller left hippocampal volumes compared to controls. Although both right and left hippocampal volumes showed nearly significant correlation with the duration of illness, this correlation reached (negative) significant levels only in the right hippocampal volume of the Val homozygotes. Conclusions. Val homozygote genotype may serve as a vulnerability factor in MDD regarding hippocampal volume loss. This finding can be considered as a supportive evidence for the neurotrophic factor hypothesis of depression.
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    Automatic Detection of Emotional Changes Induced by Social Support Loss Using fMRI
    (Ieee-Inst Electrical Electronics Engineers Inc, 2023) Candemir, Cemre; Gonul, Ali Saffet; Selver, M. Alper
    We propose using fMRI to study emotional changes related to social-support. In this respect, a Social Support fMRI task, which triggers emotional changes was designed and implemented. The detection of emotional changes from fMRI signals has significant importance in understanding the underlying mechanisms of social-support. Unfortunately, acquired signals exhibit a very low signal-to-noise ratio and strong inter-subject variations, which render the detection process a very challenging task. For this purpose, a three-phase detection system is designed. First, possible emotional change intervals are classified to isolate trivial samples and further process the challenging ones. Second, a new denoising strategy is proposed to preserve the structural waveform properties of the emotional changes, while removing noise. Third, fMRI signals are synthesized using trapezoidal modeling and a novel feature set is extracted to characterize the varying social-support levels. The analysis shows that emotional changes can be detected automatically up to a requisite level. Despite the results cannot be generalized for the entire population due to its small sample size, our findings are meaningful and suggest further research with larger datasets. The introduced task may enable further research and the proposed system may be used as a tool for social neuroscience studies.
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    Bilateral keratoconus, acute hydrops and unilateral corneal perforation due to Tourette syndrome
    (Elsevier, 2019) Palamar, Melis; Dincer, Gulsah; Teker, Mehmet Esat; Kayahan, Bulent; Gonul, Ali Saffet
    A 27-year-old male with a repetitive behavior of eyeball pressing for six months presented with decreasing visual acuity for three months. Upon arrival his best corrected visual acuity was 0.2 on the right and 0.6 on the left eyes. Scheimpflug camera system demonstrated grade 4 and grade 2 keratoconus, respectively. Psychiatric consultation revealed Tourette syndrome and treatment was started. Despite psychiatric treatment, acute hydrops occurred in both eyes decreasing visual acuity to hand motions bilaterally. Left corneal perforation due to ongoing habit of eyeball pressure was experienced which led the loss of light perception and phtisis bulbi. Although Tourette syndrome is rare, it might cause bilateral acute onset keratoconus when the repetitive movements affect periocular region. Psychiatric treatment should be considered as early as possible in these patients in order to prevent unfavorable complications.
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    Brain areas associated with resilience to depression in high-risk young women
    (Springer Heidelberg, 2021) Burhanoglu, Birce Begum; Dincer, Gulsah; Yilmaz, Alpaslan; Ozalay, Ozgun; Uslu, Ozgul; Unaran, Esmin; Gonul, Ali Saffet
    Previous structural brain-imaging studies in first-degree relatives of depressed patients showed alterations that are generally accepted as vulnerability markers for depression. However, only half of the relatives had depression at follow-up, while the other half did not. The aim of this study was to identify the brain areas associated with resilience to depression in high-risk subjects with familial depression. We recruited 59 young women with a history of depressed mothers. Twenty-nine of them (high-risk group [HRG]) had no depression history, while 30 (depressive group) had at least 1 depressive episode in adolescence. The brain structures of the groups were compared through voxel-based morphometry and analysis of cortical thickness. Individual amygdala nuclei and hippocampal subfield volumes were measured. The analysis showed larger amygdala volume, thicker subcallosal cortex and bilateral insula in the women in the HRG compared with those in the depressive group. in addition, we detected more gray matter in the left temporal pole in the HRG. The larger gray matter volume and increased cortical thickness in the key hub regions of the salience network (amygdala and insula) and structurally connected regions in the limbic network (subcallosal area and temporal pole) might prevent women in the HRG from converting to depression.
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    Brain regions associated with risk and resistance for bipolar I disorder: a voxel-based MRI study of patients with bipolar disorder and their healthy siblings
    (Wiley-Blackwell, 2014) Eker, Cagdas; Simsek, Fatma; Yilmazer, Evrim Ebru; Kitis, Omer; Cinar, Cem; Eker, Ozlem Donat; Coburn, Kerry; Gonul, Ali Saffet
    ObjectiveBipolar I disorder is a highly heritable disorder but not all siblings manifest with the illness, even though they may share similar genetic and environmental risk factors. Thus, sibling studies may help to identify brain structural endophenotypes associated with risk and resistance for the disorder. MethodsStructural magnetic resonance imaging (MRI) scans were acquired for 28 euthymic patients with bipolar disorder, their healthy siblings, and 30 unrelated healthy controls. Statistical Parametric Mapping 8 (SPM8) was used to identify group differences in regional gray matter volume by voxel-based morphometry (VBM). ResultsUsing analysis of covariance, gray matter analysis of the groups revealed a group effect indicating that the left orbitofrontal cortex [Brodmann area (BA) 11] was smaller in patients with bipolar disorder than in unrelated healthy controls [F=14.83, p<0.05 (family-wise error); 7mm(3)]. Paired t-tests indicated that the orbitofrontal cortex of patients with bipolar disorder [t=5.19, p<0.05 (family-wise error); 37mm(3)] and their healthy siblings [t=3.89, p<0.001 (uncorrected); 63mm(3)] was smaller than in unrelated healthy controls, and that the left dorsolateral prefrontal cortex was larger in healthy siblings than in patients with bipolar disorder [t=4.28, p<0.001 (uncorrected); 323mm(3)] and unrelated healthy controls [t=4.36, p<0.001 (uncorrected); 245mm(3)]. Additional region-of-interest analyses also found volume deficits in the right cerebellum of patients with bipolar disorder [t=3.92, p<0.001 (uncorrected); 178mm(3)] and their healthy siblings [t=4.23, p<0.001 (uncorrected); 489mm(3)], and in the left precentral gyrus of patients with bipolar disorder [t=3.61, p<0.001 (uncorrected); 115mm(3)] compared to unrelated healthy controls. ConclusionsThe results of this study suggest that a reduction in the volume of the orbitofrontal cortex, which plays a role in the automatic regulation of emotions and is a part of the medial prefrontal network, is associated with the heritability of bipolar disorder. Conversely, increased dorsolateral prefrontal cortex volume may be a neural marker of a resistance factor as it is part of a network of voluntary emotion regulation and balances the effects of the disrupted automatic emotion regulation system.
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    Comorbidity of psychotic disorder and substance use disorder in a psychiatry inpatient unit: A retrospective study
    (Klinik Psikiyatri Dergisi, 2018) Aldemir, Ebru; Baklaci, Umut; Gonul, Ali Saffet
    Objective: Comorbidity of psychotic disorder and substance use disorder is common. Studies demonstrate that this comorbidity constitutes a major mental health problem. The aim of this study is to investigate sociodemographic and clinical differences between illicit drug users and non-users in hospitalised male patients diagnosed with psychotic disorder. Method: This was a retrospective study evaluating files of 237 inpatients treated between January 2013 and December 2016 in Ege University Department of Psychiatry Male Inpatient Unit with diagnosis of Schizophrenia Spectrum and Other Psychotic Disorders according to DSM-5. Results: Of 237 participants, 16% had a lifetime use of an illicit drug. Participants with substance use disorder had a smaller mean age and shorter duration of education than participants without substance use disorder. Of all the participants with a history of substance use, 76.3% had a history of substance use in the first episode of psychosis. The most preferred substance in 72.4% of the participants with substance use during the first psychotic episode and in 68.4% of all the participants with substance use was cannabis. Treatment compliance was worse in the participants with substance use. Discussion: Our findings show that, when psychotic disorder is comorbid with substance use disorder, age of onset of psychotic symptoms decreases, duration of education shortens and treatment compliance deteriorates. These results should be supported by longitudinal studies using quantitative analysis methods.
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    Comparison of Alcohol Attentional Bias and Alcohol Craving Among Alcohol Abusers and Non-Abusers
    (2022) Amado, Sonia; Eker, Mehmet Çağdaş; Gonul, Ali Saffet; Türkoğlu, Sevgül
    The aim of this research is to investigate implicit cognitive process underlying alcohol craving and relationship between alcohol attentional bias and alcohol craving by using visual probe task. Current study examined whether alcohol abusers show attentional bias toward alcohol related task compared with non- abusers and causal relationship between alcohol attentional bias and alcohol craving. Firstly, participants were divided two groups (non abusers- abusers) and they were completed alcohol craving scale to determinate their alcohol craving level. Then, participants alcohol attentional bias was investigated using the visual probe task. In this task, images (alcohol-related and neutral) were presented for 500 ms on a computer screen. After that, probe (*, asterisk) was presented. Participants were asked to decide the place of the probe place by using keyboard keys within 1500 ms. Participants reaction time and number of correct and incorrect answers during the test. According to results, alcohol abuser group’s reaction times were faster than non-abuser when probe was associated with alcohol picture but not in neutral trials. These results suggested that, alcohol abusers showed significantly greater attentional bias to alcohol related pictures than non- abusers. From this point, investigation of alcohol attentional bias might be important component of alcohol dependence in terms of the alcohol relapse risk and determination of the alcohol craving.
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    Comparison of Atlas Based Segmentation and Manual Segmentation of Hippocampus
    (Ieee, 2009) Kutucu, Hakan; Eker, Cagdas; Kitis, Omer; Gonul, Ali Saffet
    High-resolution Magnetic resonance imaging (MRI) is helpful in diagnosing diseases such as schizophrenia, alzheimer, dementia etc. Brain segmentation is an important preprocess in medical imaging applications. In this study we compare atlas based segmentation and manual segmentation of hippocampus for volumetric measures. A statistically difference was obtained between automatic and manual measurement. We conclude that contemporary techniques are not adequate to obtain sensitive data in some barin structures such as hippocampus core.
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    Correlation of serum BDNF levels with hippocampal volumes in first episode, medication-free depressed patients
    (Springer Heidelberg, 2010) Eker, Cagdas; Kitis, Omer; Taneli, Fatma; Eker, Ozlem Donat; Ozan, Erol; Yucel, Kaan; Coburn, Kerry; Gonul, Ali Saffet
    The hippocampus seems to be affected in MDD, and brain-derived neurotrophic factor (BDNF) has positive effects on neurogenesis within the hippocampus. Although there are inconsistencies among study results, a smaller hippocampal volume in depressed patients is thought to be related to the pathophysiology of the disease. We looked at the correlation between serum BDNF (sBDNF) levels and hippocampal volumes (HCV) of first-episode MDD patients (18 female, 7 male; mean age = 32.1 +/- A 9.3) and healthy controls (17 female, 5 male; mean age = 29.7 +/- A 6.4). Region of interest analysis was conducted on the images acquired via MRI. sBDNF levels and HCV correlated only in the MDD group (right: r = 0.46, P = 0.02; left: r = 0.47, P = 0.02); however, HCV did not differ between MDD patients and healthy controls (right: F = 2.45, df = 1.46, P > 0.05; left: F = 0.05, df = 1.46, P > 0.05). BDNF may be a factor underlying HCV differences between MDD and healthy control subjects, which become apparent as severe and multiple episodes are experienced.
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    Cortical thickness and VBM in young women at risk for familial depression and their depressed mothers with positive family history
    (Elsevier Ireland Ltd, 2016) Ozalay, Ozgun; Aksoy, Burcu; Tunay, Sebnem; Simsek, Fatma; Chandhoki, Swati; Kitis, Omer; Eker, Cagdas; Gonul, Ali Saffet
    It has been demonstrated that compared to low-risk subjects, high-risk subjects for depression have structural and functional alterations in their brain scans even before the disease onset. However, it is not known if these alterations are related to vulnerability to depression or epiphenomena. One way to resolve this ambiguity is to detect the structural alterations in the high-risk subjects and determine if the same alterations are present in the probands. In this study, we recruited 24 women with the diagnosis of Major Depressive Disorder (MDD) with recurrent episodes and their healthy daughters (the high-risk for familial depression group; HRFD). We compared structural brain scans of the patients and HRFG group with those of 24 age-matched healthy mothers and their healthy daughters at similar ages to the HRFD group; respectively. Both cortical gray matter (GM) volume and thickness analyses revealed that HRFD daughters and their MDD mothers had similar GM differences in two regions: the right temporoparietal region and the dorsomedial prefrontal cortex. These results suggested that the observed alterations may be related to trait clinical and neurophysiological characteristics of MDD and may present before the onset of illness. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
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    Cortical thickness and VBM in young women at risk for familial depression and their depressed mothers with positive family history (vol 252, pg 1, 2016)
    (Elsevier Ireland Ltd, 2016) Ozalay, Ozgun; Aksoy, Burcu; Tunay, Sebnem; Simsek, Fatma; Chandhoke, Swati; Kitis, Omer; Eker, Cagdas; Gonul, Ali Saffet
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    Cortisol response patterns in depressed women and their healthy daughters at risk: Comparison with healthy women and their daughters
    (Pergamon-Elsevier Science Ltd, 2017) Gonul, Ali Saffet; Cetinkalp, Sevki; Tunay, Sebnem; Polat, Irmak; Simsek, Fatma; Aksoy, Burcu; Kizilates, Gozde; Erdogan, Yigit; Coburn, Kerry L.
    A dysfunctional hypothalamic pituitary adrenal (HPA) axis is widely accepted as a significant pathophysiological aspect of Major Depressive Disorder (MDD). Despite studies suggesting that a dysfunctional HPA axis might be present before the clinical syndrome becomes apparent, the functioning of the HPA axis in high risk populations has not been well defined. The aim of the present study was to investigate the HPA axis functioning of mothers suffering from MDD and their healthy daughters compared to age and sex-matched healthy controls. This design allowed a comparison of HPA axis functional differences among daughter and mother groups. HPA axis function was evaluated with a modified dexamethasone/ corticotropin-releasing hormone (Dex/CRH) test, which was performed after obtaining the diurnal adrenocorticotropic hormone (ACTH) and cortisol values at 8:00, 16:00, and 23:00 h. We found that MDD mothers and their daughters had low morning cortisol and the MDD mothers additionally had low morning ACTH compared with controls. Dexamethasone suppressed both cortisol and ACTH in all groups and subsequent HPA axis stimulation by CRH-evoked a lower cortisol response but a higher ACTH response among subjects with MDD mothers. Although high-risk daughters had comparable cortisol levels after CRH infusion, the AUC for ACTH was greater than those of controls. These patterns of results suggest that multiple level HPA dysfunctions are present in both MDD patients and their high-risk carrying daughters. However, insufficient cortisol secretion was only present in MDD mothers, while the daughters could compensate cortisol levels during CRH challenge. (C) 2016 Elsevier Ltd. All rights reserved.
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    Detection and Evaluation of Activation Instances as Change Points in Functional MR Images
    (Ieee, 2018) Candemir, Cemre; Oguz, Kaya; Korukoglu, Serdar; Gonul, Ali Saffet
    Change point analysis is an efficient method for understanding the unexpected behavior of the data used in many different disciplines including medical imaging. It is important to find the instances the activations occur as much as finding the activation areas in the analysis of functional magnetic resonance imaging (fMRI). Change point detection algorithms can be used to find the activation instances. in this study, a regression based point detection method is proposed to find the activation instances in fMRI experiments. The proposed method is applied to a fMRI experiment which includes a motor task. A linear based evaluation method is also proposed. The analyses show that the activations are in accordance with the established methods in the literature.
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    The Disrupted Connection Between Cerebral Hemispheres in Schizophrenia Patients: A Diffusion Tensor Imaging Study
    (Turkiye Sinir Ve Ruh Sagligi Dernegi, 2011) Kitis, Omer; Eker, M. Cagdas; Zengin, Burcak; Akyilmaz, Dincer Aydin; Yalvac, Dilek; Ozdemir, Halil Ibrahim; Haznedaroglu, Damla Isman; Bilgi, Mustafa Melih; Gonul, Ali Saffet
    Aim: In schizophrenia, the disruption of the communication between two brain hemispheres has not been shown clearly in the anatomical aspect despite other studies with different modalities suggested so. In this study, the structural integrity and the variables affecting the structural integrity of the corpus callosum, which is the main connection between two hemispheres, was investigated via diffusion tensor imaging (DTI). Methods: The participants were evaluated by SCID-I and symptoms of the patients were assessed with PANSS. DT images of 25 schizophrenia patients and 17 healthy volunteers were acquired via 1.5 T MR. Fractioned Anisotropy (FA) values of two groups, measured on the DT images, were compared. Results: It was found that fractioned anisotropy (FA) values were lower in the genu of the patients than the healthy controls; however, there was no difference between the FA values of the patients and the controls in the splenium. Moreover, a significant negative correlation between the splenium FA values and the antipsychotic medication doses; and a trend level negative correlation of splenium FA and PANSS scores were found. Conclusion: Corpus callosum is the most important structure that connects two frontal lobes. The hypothesis that posits the fundamental role of the disconnection of frontal lobes in schizophrenia is supported by the findings of this study.
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    Diverse Task Classification from Activation Patterns of Functional Neuro-Images Using Feature Fusion Module
    (MDPI, 2023) Biskin, Osman Tayfun; Candemir, Cemre; Gonul, Ali Saffet; Selver, Mustafa Alper
    One of the emerging fields in functional magnetic resonance imaging (fMRI) is the decoding of different stimulations. The underlying idea is to reveal the hidden representative signal patterns of various fMRI tasks for achieving high task-classification performance. Unfortunately, when multiple tasks are processed, performance remains limited due to several challenges, which are rarely addressed since the majority of the state-of-the-art studies cover a single neuronal activity task. Accordingly, the first contribution of this study is the collection and release of a rigorously acquired dataset, which contains cognitive, behavioral, and affective fMRI tasks together with resting state. After a comprehensive analysis of the pitfalls of existing systems on this new dataset, we propose an automatic multitask classification (MTC) strategy using a feature fusion module (FFM). FFM aims to create a unique signature for each task by combining deep features with time-frequency representations. We show that FFM creates a feature space that is superior for representing task characteristics compared to their individual use. Finally, for MTC, we test a diverse set of deep-models and analyze their complementarity. Our results reveal higher classification accuracy compared to benchmarks. Both the dataset and the code are accessible to researchers for further developments.
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    The effect of emotional faces on reward-related probability learning in depressed patients
    (Elsevier, 2024) Keskin-Gokcelli, Duygu; Kizilates-Evin, Gozde; Eroglu-Koc, Seda; Oguz, Kaya; Eraslan, Cenk; Kitis, Omer; Gonul, Ali Saffet
    Background: Existing research indicates that individuals with Major Depressive Disorder (MDD) exhibit a bias toward salient negative stimuli. However, the impact of such biased stimuli on concurrent cognitive and affective processes in individuals with depression remains inadequately understood. This study aimed to investigate the effects of salient environmental stimuli, specifically emotional faces, on reward-associated processes in MDD. Methods: Thirty-three patients with recurrent MDD and thirty-two healthy controls (HC) matched for age, sex, and education were included in the study. We used a reward-related associative learning (RRAL) task primed with emotional (happy, sad, neutral) faces to investigate the effect of salient stimuli on reward-related learning and decision-making in functional magnetic resonance imaging (fMRI). Participants were instructed to ignore emotional faces during the task. The fMRI data were analyzed using a full-factorial general linear model (GLM) in Statistical Parametric Mapping (SPM12). Results: In depressed patients, cues primed with sad faces were associated with reduced amygdala activation. However, both HC and MDD group exhibited reduced ventral striatal activity while learning reward-related cues and receiving rewards. Limitations: The patients'medication usage was not standardized. Conclusions: This study underscores the functional alteration of the amygdala in response to cognitive tasks presented with negative emotionally salient stimuli in the environment of MDD patients. The observed alterations in amygdala activity suggest potential interconnected effects with other regions of the prefrontal cortex. Understanding the intricate neural connections and their disruptions in depression is crucial for unraveling the complex pathophysiology of the disorder.
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    The effect of previous psychotic mood episodes on cognitive impairment in euthymic bipolar patients
    (Blackwell Publishing, 2007) Bora, Emre; Vahip, Simavi; Akdeniz, Fisun; Gonul, Ali Saffet; Eryavuz, Ayse; Ogut, Melise; Alkan, Muge
    Objectives: Cognitive dysfunctions in several domains were proposed to be trait markers of bipolar patients. The aim of this study was to evaluate the effect of previous psychotic features on neuropsychological measures, including sustained attention, in remitted bipolar patients. Methods: The study participants were 40 euthymic psychotic, 25 non-psychotic bipolar I patients and 30 healthy control subjects. Participants were assessed with a battery of neuropsychological tests targeting attention, executive functions, psychomotor speed, verbal learning and memory. Results: Euthymic psychotic bipolar patients performed worse than controls on most of the measures, after controlling for the confounding effects of education, age and residual symptoms. Non-psychotic patients were also impaired on tasks of attention, fluency and psychomotor speed. 'Number of Wisconsin Card Sorting Test (WCST) categories' achieved was the only measure on which psychotic patients performed significantly worse compared to non-psychotic patients. Differences among patient groups were not explained by illness severity measures. The duration of illness was related to slowness in psychomotor speed tasks. Verbal memory deficits may be related to serum lithium levels and age of onset of disease. Conclusions: Deficits in cognitive flexibility may be a candidate for being a trait marker of psychotic features among bipolar patients. However, verbal fluency, psychomotor speed and sustained attention deficits may be candidates for vulnerability indicators of bipolar disorder in general.