Objective:Using graph theory analysis, this study compares the topological and node attributes of the brain network to explore the differences in gray matter structural and functional network topological properties between bipolar depression (BD) patients with and without obsessive-compulsive symptoms (OCS).Methods:A total of 90 BD patients (27 males, 63 females; median age 19.0(22.0, 25.0) years) were recruited from the psychiatric outpatient and inpatient departments of the First Affiliated Hospital of Jinan University between March 2018 and December 2022. Fifty healthy controls (19 males, 31 females; median age: 23.0 (20.0, 27.0) years) were also enrolled. The BD patients were divided into two groups based on the presence of OCS: 53 with OCS (OCS group) and 37 without OCS (NOCS group). Resting-state structural and functional MRI data were collected for all participants to construct gray matter structural and functional networks. Graph therory analysis was applied to calculate network topological metrics such as small-world properties. The structural and functional network topological properties were compared among the BD-OCS, BD-nOCS, and control groups. Partial correlation analysis was conducted to examine the association between network topological metrics with significant group differences and Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores. Support vector machines (SVM) were used with these metrics as classification feature values to improve diagnostic accuracy through pairwise group classification.Results:Structural network analysis of gray matter: compared to HC group, both OCS group and NOCS group showed increased shortest path length and standardized characteristic path length (shortest path length: 0.78 and 0.80 vs. 0.69; normalized characteristic path length: 0.48 and 0.49 vs. 0.43), and decreased global efficiency (0.21 and 0.21 vs. 0.24) compared to the HC group (permutation test, all P<0.05). Compared to NOCS and HC groups, the OCS group showed increased nodal centrality and betweenness centrality in the right rolandic operculum and left superior occipital gyrus (permutation test, all P<0.05). Functional network analysis of gray matter: compared to the NOCS group, the OCS group showed increased node efficiency and decreased betweenness centrality in the cerebellum ( t=2.15, -3.04; all P<0.05); compared to HC groups, the OCS group showed decreased betweenness centrality in the cerebellum and left inferior frontal gyrus, along with increased node centrality and nodal efficiency in the right transverse temporal gyrus ( t=-2.99, -3.61, 3.06, 3.10; all P<0.05). In the OCS group, betweenness centrality in the left inferior frontal gyrus positively correlated with Y-BOCS scale obsessive thinking score ( r=0.303, P=0.034). Nodal centrality and node efficiency of the right transverse temporal gyrus negatively correlated with Y-BOCS total score ( r=-0.301, -0.311) and Y-BOCS obsessional thinking scores ( r=-0.385, -0.380) separately(all P<0.05). SVM classification: the combined network features achieved an area under the curve of 0.80 in distinguising OCS from NOCS patients. Conclusion:BD-OCS and BD-nOCS patients both exhibit consistent changes in gray matter structural network topology, with the OCS group displaying more pronounced nodal topological abnormalities. Multi-network feature integration demostrates potential for diagnostic classfication.

Anhedonia is one of the core symptoms of major depressive disorder, and its underlying mechanisms remain unclear. The regulation of the reward process in brain regions, such as the hippocampus, amygdala, striatum, ventral tegmental brain, and prefrontal lobe, may play a role in anhedonia. This study has concluded the changes in relevant brain regions in reward anticipation, decision-making, and feedback processes. The neuroimaging mechanisms of inflammation, neurotransmitter metabolism, and gene expression on depression anhedonia symptoms were reviewed.

Gender identity disorder, also known as transsexualism, has an unclear pathogenesis. Compared to cisgender individuals with this condition may exhibit specific alterations in brain gray matter, white matter, brain network, and metabolism. This article aims to summarize the brain imaging researches related to gender dysphoria, and to provide a review of the research findings on the brain structure and function for further research in this field.

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Rumination is a core cognitive symptom of post-traumatic stress disorder(PTSD),which significantly exacerbates difficulties in emotional regulation and impedes symptom recovery.Its occurrence is closely associated with gray matter structural impairments and abnormal white matter connectivity in the prefrontal-limbic system,including the hippocampus,amygdala,and prefrontal cortex.Functional neuroimaging studies indicate that the neural basis of rumination involves hyperactivation of the default mode network and the salience network,coupled with reduced functionality of the executive control network.Neurochemical research suggests that metabolic imbalances in the glutamate/γ-aminobutyric acid system may further contribute to the maintenance and reinforcement of rumination.Systematically elucidating the neural mechanisms of rumination in PTSD patients based on multimodal neuroimaging evidence will facilitate a deeper understanding of its neuropathological mechanisms and help expand future research directions.

The prevalence of comorbidity of eating disorders(ED)and bipolar disorder(BD)is high,and patients with comorbid conditions often have a high risk of suicide and poor prognosis.Exploring the pathogenesis of BD comorbid with ED is of great significance for improving clinical efficacy and adverse prognosis in patients.The mechanisms underlying BD comorbid ED remain unclear,involving multifaceted neurobiological factors such as serotonin system dysfunction,dopamine reward pathway disruption,abnormal immune system activation,fluctuations in sex hormone levels,and functional and structural abnormalities in brain regions associated with emotional control and reward system pathways.Therefore,this article provides ideas for the research direction of BD comorbid with ED by analyzing the roles of genetic metabolism,neurobiochemistry,immune,and imaging changes in the comorbidity mechanism.

Rumination is a core cognitive symptom of post-traumatic stress disorder(PTSD),which significantly exacerbates difficulties in emotional regulation and impedes symptom recovery.Its occurrence is closely associated with gray matter structural impairments and abnormal white matter connectivity in the prefrontal-limbic system,including the hippocampus,amygdala,and prefrontal cortex.Functional neuroimaging studies indicate that the neural basis of rumination involves hyperactivation of the default mode network and the salience network,coupled with reduced functionality of the executive control network.Neurochemical research suggests that metabolic imbalances in the glutamate/γ-aminobutyric acid system may further contribute to the maintenance and reinforcement of rumination.Systematically elucidating the neural mechanisms of rumination in PTSD patients based on multimodal neuroimaging evidence will facilitate a deeper understanding of its neuropathological mechanisms and help expand future research directions.

The prevalence of comorbidity of eating disorders(ED)and bipolar disorder(BD)is high,and patients with comorbid conditions often have a high risk of suicide and poor prognosis.Exploring the pathogenesis of BD comorbid with ED is of great significance for improving clinical efficacy and adverse prognosis in patients.The mechanisms underlying BD comorbid ED remain unclear,involving multifaceted neurobiological factors such as serotonin system dysfunction,dopamine reward pathway disruption,abnormal immune system activation,fluctuations in sex hormone levels,and functional and structural abnormalities in brain regions associated with emotional control and reward system pathways.Therefore,this article provides ideas for the research direction of BD comorbid with ED by analyzing the roles of genetic metabolism,neurobiochemistry,immune,and imaging changes in the comorbidity mechanism.

Objective:Using graph theory analysis, this study compares the topological and node attributes of the brain network to explore the differences in gray matter structural and functional network topological properties between bipolar depression (BD) patients with and without obsessive-compulsive symptoms (OCS).Methods:A total of 90 BD patients (27 males, 63 females; median age 19.0(22.0, 25.0) years) were recruited from the psychiatric outpatient and inpatient departments of the First Affiliated Hospital of Jinan University between March 2018 and December 2022. Fifty healthy controls (19 males, 31 females; median age: 23.0 (20.0, 27.0) years) were also enrolled. The BD patients were divided into two groups based on the presence of OCS: 53 with OCS (OCS group) and 37 without OCS (NOCS group). Resting-state structural and functional MRI data were collected for all participants to construct gray matter structural and functional networks. Graph therory analysis was applied to calculate network topological metrics such as small-world properties. The structural and functional network topological properties were compared among the BD-OCS, BD-nOCS, and control groups. Partial correlation analysis was conducted to examine the association between network topological metrics with significant group differences and Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores. Support vector machines (SVM) were used with these metrics as classification feature values to improve diagnostic accuracy through pairwise group classification.Results:Structural network analysis of gray matter: compared to HC group, both OCS group and NOCS group showed increased shortest path length and standardized characteristic path length (shortest path length: 0.78 and 0.80 vs. 0.69; normalized characteristic path length: 0.48 and 0.49 vs. 0.43), and decreased global efficiency (0.21 and 0.21 vs. 0.24) compared to the HC group (permutation test, all P<0.05). Compared to NOCS and HC groups, the OCS group showed increased nodal centrality and betweenness centrality in the right rolandic operculum and left superior occipital gyrus (permutation test, all P<0.05). Functional network analysis of gray matter: compared to the NOCS group, the OCS group showed increased node efficiency and decreased betweenness centrality in the cerebellum ( t=2.15, -3.04; all P<0.05); compared to HC groups, the OCS group showed decreased betweenness centrality in the cerebellum and left inferior frontal gyrus, along with increased node centrality and nodal efficiency in the right transverse temporal gyrus ( t=-2.99, -3.61, 3.06, 3.10; all P<0.05). In the OCS group, betweenness centrality in the left inferior frontal gyrus positively correlated with Y-BOCS scale obsessive thinking score ( r=0.303, P=0.034). Nodal centrality and node efficiency of the right transverse temporal gyrus negatively correlated with Y-BOCS total score ( r=-0.301, -0.311) and Y-BOCS obsessional thinking scores ( r=-0.385, -0.380) separately(all P<0.05). SVM classification: the combined network features achieved an area under the curve of 0.80 in distinguising OCS from NOCS patients. Conclusion:BD-OCS and BD-nOCS patients both exhibit consistent changes in gray matter structural network topology, with the OCS group displaying more pronounced nodal topological abnormalities. Multi-network feature integration demostrates potential for diagnostic classfication.

Anhedonia is one of the core symptoms of major depressive disorder, and its underlying mechanisms remain unclear. The regulation of the reward process in brain regions, such as the hippocampus, amygdala, striatum, ventral tegmental brain, and prefrontal lobe, may play a role in anhedonia. This study has concluded the changes in relevant brain regions in reward anticipation, decision-making, and feedback processes. The neuroimaging mechanisms of inflammation, neurotransmitter metabolism, and gene expression on depression anhedonia symptoms were reviewed.