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Background: Previous studies suggested a link between serotonergic neurotransmission and impaired insight in schizophrenia. In this study, we examined the relationship between serotonin transporter (SERT) availability in regions of the prefrontal cortex (dorsolateral, ventrolateral, ventromedial, and orbitofrontal cortices) and insight deficits in antipsychotic-free patients with schizophrenia using high-resolution positron emission tomography (PET) with [11C]DASB. Methods: Nineteen patients underwent [11C]DASB PET and 7-Tesla magnetic resonance imaging scans. To assess SERT availability, the binding potential with respect to non-displaceable compartment (BPND) was derived using the simplified reference tissue model. Patients' level of insight was assessed using the Insight and Treatment Attitude Questionnaire (ITAQ). The relationship between ITAQ scores and [11C]DASB BPND values was examined using the region-of-interest (ROI)- and voxel-based analyses with relevant variables as covariates. The prefrontal cortex and its four subregions were selected as a priori ROIs since the prefrontal cortex has been implicated as the critical neuroanatomical substrate of impaired insight in schizophrenia. Results: The ROI-based analysis revealed that the ITAQ illness insight dimension had significant negative correlations with the [11C]DASB BPND in the left dorsolateral, left orbitofrontal, and bilateral ventrolateral prefrontal cortices. The ITAQ treatment insight dimension had significant negative correlations with the [11C]DASB BPND in the bilateral dorsolateral, left orbitofrontal, and bilateral ventrolateral prefrontal cortices. The ITAQ total score showed significant negative correlations with the [11C]DASB BPND in the bilateral prefrontal cortex and three subregions (dorsolateral, ventrolateral, and orbitofrontal cortices). A supplementary voxel-based analysis corroborated a significant negative association between the ITAQ score and the [11C]DASB BPND in the prefrontal cortices. Conclusion: Our study provides in vivo evidence of significant negative correlations between insight deficits and prefrontal SERT availability in patients with schizophrenia, suggesting significant involvement of prefrontal serotonergic signaling in impaired insight, one of the core symptoms of schizophrenia. [ABSTRACT FROM AUTHOR]

Background: Continuous mouth breathing results not only morphological deformations but also poor learning outcomes. However, there were few studies that observed correlations between mouth breathing and cognition. This study aimed at investigating the changes in brain activity during mouth breathing while the participant simultaneously performed a cognitive task using electroencephalography (EEG). Methods: Twenty subjects participated in this study, and EEG electrodes (32 channels, 250-Hz sampling rate) were placed on their scalp. Brain waves during a resting state and n-back tasks (0-back and 2-back) and physiological parameters such as SpO2, ETCO2, and the airway respiratory rate were measured. The pre-processed EEG signals were analyzed based on their frequencies as delta waves (0.5 ∼ 4 Hz), theta waves (4 ∼ 8 Hz), alpha waves (8 ∼ 13 Hz), beta waves (13 ∼ 30 Hz) and gamma waves (30 ∼ 50 Hz) using fast Fourier transform (FFT). Results: When compared with nose breathing, theta and alpha powers were lower during mouth breathing at rest and alpha wave presented low power at 0-back and 2-back tasks. Furthermore, beta and gamma waves exhibited low powers at 2-back task. However, the behavioral results (accuracy and response time) have no significant difference between two breathing methods (mouth and nose). Mouth breathing showed different brain activity patterns, compared to nose breathing, and these changes are related to cognitive regions. Conclusion: The reason for this change seems to relate to the decreased oxygen saturation during mouth breathing, suggesting that when cognitive abilities are required, mouth breathing can act as one of the variables that cause different outcomes in brain activities. [ABSTRACT FROM AUTHOR]

Background: Refugees commonly experience difficulties with emotional processing, such as alexithymia, due to stressful or traumatic experiences. However, the functional connectivity of the amygdala, which is central to emotional processing, has yet to be assessed in refugees. Thus, the present study investigated the resting-state functional connectivity of the amygdala and its association with emotional processing in North Korean (NK) refugees. Methods: This study included 45 NK refugees and 40 native South Koreans (SK). All participants were administered the Toronto Alexithymia Scale (TAS), Beck Depression Inventory (BDI), and Clinician-administered PTSD Scale (CAPS), and differences between NK refugees and native SK in terms of resting-state functional connectivity of the amygdala were assessed. Additionally, the association between the strength of amygdala connectivity and the TAS score was examined. Results: Resting-state connectivity values from the left amygdala to the bilateral dorsolateral prefrontal cortex (dlPFC) and dorsal anterior cingulate cortex (dACC) were higher in NK refugees than in native SK. Additionally, the strength of connectivity between the left amygdala and right dlPFC was positively associated with TAS score after controlling for the number of traumatic experiences and BDI and CAPS scores. Conclusions: The present study found that NK refugees exhibited heightened frontal–amygdala connectivity, and that this connectivity was correlated with alexithymia. The present results suggest that increased frontal–amygdala connectivity in refugees may represent frontal down-regulation of the amygdala, which in turn may produce alexithymia. [ABSTRACT FROM AUTHOR]