Akgül, Özge
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Akgul, Ozge
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ozge.akgul@ieu.edu.tr
Main Affiliation
02.04. Psychology
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Former Staff
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Sustainable Development Goals
Documents
13
Citations
79
h-index
3
Documents
19
Citations
74
Scholarly Output
5
Articles
5
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0/0
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0
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0
WoS Citation Count
43
Scopus Citation Count
46
WoS h-index
2
Scopus h-index
2
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0
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0
WoS Citations per Publication
8.60
Scopus Citations per Publication
9.20
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0
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0
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5 results
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Article Citation - WoS: 1Citation - Scopus: 1Enhanced Punishment Responses in Patients With Schizophrenia: an Event-Related Potential Study(Sage Publications Inc, 2023) Akgül, Özge; Fide, Ezgi; Özel, Fatih; Alptekin, Koksal; Bora, Emre; Akdede, Berna Binnur; Yener, GorsevIt is well known that abnormal reward processing is a characteristic feature of various psychopathologies including schizophrenia. Reduced reward anticipation has been suggested as a core symptom of schizophrenia. The Monetary Incentive Delay Task (MID) is frequently used to detect reward anticipation. The present study aims to evaluate the amplitude and latency of event-related potential (ERP) P300 in patients with schizophrenia (SCH) compared to healthy controls during the MID task. Twenty patients with SCH and 21 demographically matched healthy controls (HC) were included in the study. ERP P300 amplitude and latency values were compared between groups using an MID task in which reward and loss cues were presented. Relations between P300 and clinical facets were investigated in the patient group. SCH group had enhanced mean P300 amplitudes and delayed peak latency in the punishment condition compared with HC. These higher responses were also associated with negative symptoms. SCH group showed altered reward processing as being more sensitive to loss of reward conditions as firstly evidenced by electrophysiological methods, possibly due to abnormality in various systems including social withdrawal, social defeat, and behavioral inhibition system.Article Citation - WoS: 1Reduced Reward Processing in Schizophrenia: a Comprehensive Eeg Event-Related Oscillation Study(Springer, 2023) Akgül, Özge; Fide, Ezgi; Özel, Fatih; Alptekin, Köksal; Bora, Emre; Akdede, Berna Binnur; Yener, GörsevIt is well known that abnormal reward processing is a characteristic feature of various psychopathologies including schizophrenia (SZ). Reduced reward anticipation has been suggested as a core symptom of SZ. The present study aims to evaluate the event-related oscillations (EROs) delta, theta, alpha, beta, and gamma in patients with SZ during the Monetary Incentive Delay (MID) task, which elicits the neural activity of reward processing. Twenty-one patients with SZ and twenty-two demographically matched healthy controls were included in the study. EROs were compared between groups and correlation analyses were conducted to determine a possible relationship between clinical scores and ERO values. Compared with healthy controls, the SZ group had reduced (1) delta and theta amplitudes in the reward condition (2) total beta and non-incentive cue-related beta amplitudes, and (3) incentive cue-related frontal gamma amplitudes. These reductions can be interpreted as impaired dopaminergic neurotransmission and disrupted cognitive functioning in the reward processing of SZ. In contrast, SZ patients showed higher incentive cue-related theta and occipital gamma amplitudes compared to controls. These increments may reflect negative symptoms in SZ. Moreover, theta amplitudes showed a negative correlation with Calgary Depression Scale for Schizophrenia scores and a positive correlation with attentional impulsivity. This is the first study showing the impairments of SZ patients in EROs from delta to gamma frequency bands compared with healthy controls during reward anticipation. Being the first comprehensive study, our results can be interpreted as providing evidence for disrupted brain dynamics in the reward processing of SZ studied by EROs. It may become possible to help patients' wellness by improving our understanding of reward processing in schizophrenia and developing innovative rehabilitation treatments based on these findings.Article Transdiagnostic Investigation of White Matter Integrity and Cortical Thickness in Cognitive Subgroups Within the Schizophrenia-Bipolar Spectrum(Elsevier Ireland Ltd, 2026) Verim, Burcu; Demirlek, Cemal; Zorlu, Nabi; Erdeniz, Burak; Akgul, Ozge; Ceylan, Deniz; Bora, EmreBackground: Cognitive deficits are cardinal features of schizophrenia-spectrum disorders (SSD) and bipolar disorder (BD). However, their heterogeneous and overlapping characteristics require a dimensional approach to better understand the neurobiological basis of cognition in the psychosis spectrum. To date, only a few studies have examined the neuroanatomical features of cognitive subgroups in transdiagnostic samples, and white matter microstructural characteristics of these subgroups have not been elucidated. This study aimed to investigate white matter and cortical thickness alterations in cognitive subgroups in the schizophrenia-bipolar spectrum. Methods: Globally Impaired (n = 31) and Near-Normal (n = 28) cognitive subgroups, comprising individuals diagnosed with schizophrenia (SZ), schizoaffective disorder (SAD) or BD, and healthy controls (HCs, n = 29), underwent 3T T1-weighted structural magnetic resonance imaging and diffusion tensor imaging scanning. Fractional anisotropy and cortical thickness measures were compared between the cognitive subgroups and healthy controls. Results: Abnormalities in white matter microstructure were only observed in patients with global cognitive impairment compared to HCs. The Near-Normal subgroup did not differ from HCs in white matter integrity. A bilateral reduction in cortical thickness was observed in both the Globally Impaired and Near-Normal subgroups when compared to HCs. Cortical thickness measures did not differentiate between the cognitive subgroups. Conclusions: While reductions in cortical thickness in frontal and temporal regions appear to be a common feature of SZ and BD, abnormalities in white matter microstructure are associated with global cognitive impairment in the schizophrenia-bipolar spectrum. These original findings may be important in identifying more biologically valid clinical syndromes within the schizophrenia-bipolar spectrum.Article Citation - WoS: 2Citation - Scopus: 3Early and Late Contingent Negative Variation (cnv) Reflect Different Aspects of Deficits in Schizophrenia(Wiley, 2024) Akgül, Özge; Fide, Ezgi; Özel, Fatih; Alptekin, Köksal; Bora, Emre; Akdede, Berna Binnur; Yener, GörsevAbnormal reward processing and psychomotor slowing are well-known in schizophrenia (SZ). As a slow frontocentral potential, contingent negative variation (CNV) is associated with anticipatory attention, motivation and motor planning. The present study aims to evaluate the early and late amplitude and latencies of CNV in patients with SZ compared to healthy controls during a reward processing task and to show its association with clinical symptoms. We recruited 21 patients with SZ and 22 healthy controls to compare early and late CNV amplitude and latency values during a Monetary Incentive Delay (MID) Task between groups. Patients' symptom severity, levels of negative symptoms and depressive symptoms were assessed. Clinical features of the patients were further examined for their relation with CNV components. In conclusion, we found decreased early CNV amplitudes in SZ during the reward condition. They also displayed diminished and shortened late CNV responses for incentive cues, specifically at the central location. Furthermore, early CNV amplitudes exhibited a significant correlation with positive symptoms. Both CNV latencies were linked with medication dosage and the behavioural outcomes of the MID task. We revealed that early and late CNV exhibit different functions in neurophysiology and correspond to various facets of the deficits observed in patients. Our findings also emphasized that slow cortical potentials are indicative of deficient motivational processes as well as impaired reaction preparation in SZ. To gain a deeper understanding of the cognitive and motor impairments associated with psychosis, future studies must compare the effects of CNV in the early and late phases. The aim was to evaluate the early and late amplitude and latencies of CNV in schizophrenia (SZ) patients compared to healthy controls (HC) during a reward processing task. Decreased early CNV amplitudes in SZ during the reward condition, and diminished and shortened late CNV responses for incentive cues were found. Early CNV amplitudes exhibited a significant correlation with positive symptoms. Both CNV latencies were linked with medication dosage and the behavioural outcomes of the MID task. imageReview Article Citation - WoS: 39Citation - Scopus: 42Neurological Soft Signs in Bipolar Disorder in Comparison To Healthy Controls and Schizophrenia: a Meta-Analysis(Elsevier, 2018) Bora, Emre; Akgul, Ozge; Ceylan, Deniz; Ozerdem, AysegulNeurological soft signs (NSS) are subtle deficits in motor coordination, sensory integration, and sequencing of complex motor acts. Increased NSS is a well-established feature of patients with schizophrenia but a relatively smaller number of studies have investigated NSS in bipolar disorder (BD). Some authors but not others suggested that NSS can distinguish schizophrenia from BD. We conducted a meta-analysis of 18 studies to quantitatively review NSS in BD in comparison to schizophrenia and healthy controls. The current meta-analysis compared NSS scores of 725 BD patients and 634 healthy controls, and 391 BD and 471 schizophrenia patients. Patients with BD had significantly higher NSS scores (d = 1.14, CI = 0.89-1.44) than healthy controls and increased scores in BD was evident in all aspects of NSS (d = 0.88-0.99). BD was associated with a less severe increase in NSS compared to schizophrenia, however, between-group difference was modest (d = 0.42, CI = 0.18-0.65). The results of this meta-analysis demonstrated that BD is characterized by a robust increase in NSS which is only moderately less severe than schizophrenia. Increased NSS is a common feature of both disorders. (c) 2018 Elsevier B.V. and ECNP. All rights reserved.
