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Background: Abnormalities in white matter (WM) may be a crucial physiologic feature of Alzheimer's disease (AD). However, neuroimaging's ability to visualize the underlying functional degradation of the WM region in AD is unclear. Objective: This study aimed to explore the differences in amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF) in the WM region of patients with AD and healthy controls (HC) and to investigate further whether these values can provide supplementary information for diagnosing AD. Methods: Forty-eight patients with AD and 46 age-matched HC were enrolled and underwent resting-state functional magnetic resonance imaging and a neuropsychological battery assessment. We analyzed the differences in WM activity between the two groups and further explored the correlation between WM activity in the different regions and cognitive function in the AD group. Finally, a machine learning algorithm was adopted to construct a classifier in detecting the clinical classification ability of the values of ALFF/ALFF in the WM. Results: Compared with HCs, patients with AD had lower WM activity in the right anterior thalamic radiation, left frontal aslant tract, and left forceps minor, which are all positively related to global cognitive function, memory, and attention function (all p < 0.05). Based on the combined WM ALFF and fALFF characteristics in the different regions, individuals not previously assessed were classified with moderate accuracy (75%), sensitivity (71%), specificity (79%), and area under the receiver operating characteristic curve (85%). Conclusion: Our results suggest that WM activity is reduced in AD and can be used for disease classification. [ABSTRACT FROM AUTHOR]

Introduction: Somatic symptoms often occur as a manifestation of depression and anxiety. The subgenual anterior cingulate cortex (sgACC) has been shown to be closely related to both depression and anxiety and plays an important role in somatic symptoms. However, little is known regarding whether the abnormal function of the sgACC contributes to the common somatic symptoms of depression and anxiety. Methods: Resting-state functional connectivity (RSFC) analysis based on the seed of the sgACC was investigated in 23 major depressive disorder (MDD) patients with somatic symptoms, 20 generalized anxiety disorder (GAD) patients with somatic symptoms, and 22 demographically matched healthy controls (HCs). The severity of depression, anxiety, and somatic symptoms was assessed using the Hamilton Depression Rating Scale (HAMD), Hamilton Anxiety Rating Scale (HAMA), and the 15-item somatic symptom severity scale from the Patient Health Questionnaire (PHQ-15), respectively. An analysis of covariance analysis (ANCOVA) was conducted to determine RSFC alterations among GAD, MDD, and HC groups with age, gender, and head motion as covariates. Correlation analyses were conducted between the RSFC of the sgACC and PHQ-15. Results: The significantly different RSFC of right sgACC among the three groups was found in right STG, left cerebellum, and right postcentral. Post hoc analysis indicated that both MDD and GAD patients showed a decreased RSFC between the right sgACC and right STG than HCs, and both were negatively correlated with the PHQ-15 scores. Conclusion: The abnormally decreased RSFC of the sgACC and STG may be the underlying common mechanisms of depression and anxiety combined with somatic symptoms. [ABSTRACT FROM AUTHOR]

White matter hyperintensities (WMHs) are commonly observed in older adults and are associated with cognitive impairment. Although previous studies have found abnormal functional connectivities in patients with WMHs based on static functional magnetic resonance imaging (fMRI), the topological properties in the context of brain dynamics remain relatively unexplored. Herein, we explored disrupted dynamic topological properties of functional network connectivity in patients with WMHs and its relationship with cognitive impairment. We included 36 healthy controls (HC) and 104 patients with mild WMHs (n = 39), moderate WMHs (n = 37), and severe (n = 28) WMHs. The fMRI data of all participants were analyzed using Anatomical Automatic Labeling (AAL) and a sliding-window approach to generate dynamic functional connectivity matrics. Then, graph theory methods were applied to calculate the topological properties. Comprehensive neuropsychological scales were used to assess cognitive functions. Relationships between cognitive functions and abnormal dynamic topological properties were evaluated by Pearson's correlation. We found that the patients with WMHs had higher temporal variability in regional properties, including betweenness centrality, nodal efficiencies, and nodal clustering coefficient. Furthermore, we found that the degree of centrality was related to executive function and memory, and the local coefficient correlated to executive function. Our results indicate that patients with WMHs have higher temporal variabilities in regional properties and are associated with executive and memory function. [ABSTRACT FROM AUTHOR]

Linguistic deficits are frequent symptoms among stroke survivors. The neural mechanism of post-stroke aphasia (PSA) was incompletely understood. Recently, resting-state functional magnetic resonance imaging (rs-fMRI) was widely used among several neuropsychological disorders. However, previous rs-fMRI studies of PSA were limited to very small sample size and the absence of reproducibility with different neuroimaging indexes. The present study performed comparisons with static and dynamic amplitude of low-frequency fluctuations (ALFF) and functional connectivity (FC) based on modest sample size (40 PSA and 37 healthy controls). Compared with controls, PSA showed significantly increased static ALFF predominantly in the bilateral supplementary motor area (SMA) and right hippocampus-parahippocampus (R HIP-ParaHip) and decreased static ALFF in right cerebellum. The increased dynamic ALFF in SMA and decreased dynamic ALFF in right cerebellum were also found in PSA. The static and dynamic ALFF in right cerebellum was positively correlated with spontaneous speech. The FC between the SMA and R HIP-ParaHip was significantly stronger in patients than controls and positively correlated with ALFF in bilateral SMA. In addition, the FC between the R HIP-ParaHip and the right temporal was also enhanced in patients and negatively correlated with repetition, naming, and comprehension score. These findings revealed consistently abnormal intrinsic neural activity in SMA and cerebellum, which may underlie linguistic deficits in PSA. [ABSTRACT FROM AUTHOR]

Characterizing the properties of brain networks across mood states seen in bipolar disorder (BP) can provide a deeper insight into the mechanisms involved in this type of affective disorder. In this study, graph theoretical methods were used to examine global, modular and nodal brain network topology in the resting state using functional magnetic resonance imaging data acquired from 95 participants, including those with bipolar depression (BPD; n = 30) and bipolar mania (BPM; n = 39) and healthy control (HC) subjects (n = 26). The threshold value of the individual subjects' connectivity matrix varied from 0.15 to 0.30 with steps of 0.01. We found that: (1) at the global level, BP patients showed a significantly increased global efficiency and synchronization and a decreased path length; (2) at the nodal level, BP patients showed impaired nodal parameters, predominantly within the frontoparietal and limbic sub-network; (3) at the module level, BP patients were characterized by denser FCs (edges) between Module III (the front-parietal system) and Module V (limbic/paralimbic systems); (4) at the nodal level, the BPD and BPM groups showed state-specific differences in the orbital part of the left superior-frontal gyrus, right putamen, right parahippocampal gyrus and left fusiform gyrus. These results revealed abnormalities in topological organization in the whole brain, especially in the frontoparietal-limbic circuit in both BPD and BPM. These deficits may reflect the pathophysiological processes occurring in BP. In addition, state-specific regional nodal alterations in BP could potentially provide biomarkers of conversion across different mood states. [ABSTRACT FROM AUTHOR]

Background : Alzheimer's disease (AD) manifests differently in males and females. However, the neuro-mechanism and influence factors are still unknown. Objective : To explore sex differences in brain network topology during AD disease progression and its association with cognition and possible influencing factors. Methods : Resting-state functional magnetic resonance imaging (MRI) data and cognitive scores were collected from 82 AD patients (50 females), 56 amnestic mildly cognitive impaired patients (29 females), and 63 healthy controls (38 females). Global and regional topological network metrics and modular architecture were calculated. Two-way ANOVA was performed to explore group and sex interactions and their main effects. Mediation analysis was used to explore the relationship among education, inter/intra-network connectivity, and the Mini-Mental State Examination (MMSE) score. Results : Lower levels of education, lower MMSE scores, and a positive correlation between the level of education and MMSE scores were found in female AD patients (p = 0.024, r = 0.319). Significantly lower connectivity strength within the sensorimotor network, dorsal attention network, ventral attention network (VAN), and between the sensorimotor and VAN were observed in male AD patients (p = 0.006, 0.028, 0.046, and 0.013, respectively). Group and sex interactions were also found in nodal properties, mainly in the frontal lobe, temporal lobe, middle cingulum, precuneus, and postcentral gyrus. Several of the altered brain network properties were associated with cognitive behavior in male AD patients. Education regulated the MMSE score through the mediation of connection strength between the default mode and limbic networks (LN) in the patient group (aMCI and AD combined). Conclusion : Our results demonstrate that sex differences exist at the brain network level in AD. Sex differences in network topology and education are correlated with sex differences in cognition during AD progression. [ABSTRACT FROM AUTHOR]

Background: White matter hyperintensities (WMH)s is a very common neuroradiological manifestation in the elderly and is an increased risk of dementia and cognitive decline. As we all know, the thalamocortical circuit plays an important part in cognition regulation. However, the role of this circuit in WMHs and its related cognitive deficits is still unclear. Method: Eighty WMH patients and 37 healthy controls (HCs) were enrolled in the current study. WMH patients were divided into a mild WMH group (n = 33) and moderate-severe WMH group (n = 47) according to Fazekas scores. Resting-state functional magnetic resonance imaging (rs-fMRI) data of all participants were collected for thalamocortical functional connectivity (FC) analysis. The analysis was performed in two steps. First, the whole cerebral cortex was divided into six regions of interest (ROIs), which were used as seeds to investigate the changes of FC with the thalamus. Then, the subregion of the thalamus generated in the previous step was used as the seed for FC analysis with the whole brain. Results: In the first step of FC analysis, it was found that precentral gyrus (PrCG)-interthalamic adhesion (ITA) FC values in moderate-severe WMH group were higher than those in HC and mild WMH groups. However, when compared with the HC group, the increase of PrCG-ITA FC values in mild WMH group was not statistically significant. In the second step of FC analysis, the ITA was set as the seed, and compared with the HC group, the results showed that the FC values of the ITA-medial frontal gyrus (MFG) in mild group and moderate-severe WMH groups were significantly increased. In addition, the FC values in moderate-severe group were significantly higher than those in mild group. Finally, it was also found that FC values (PrCG-ITA and ITA-MFG) were significantly correlated with neuropsychological test results for multiple cognitive functions such as memory, execution and attention in WMH patients. Conclusion: Abnormal thalamocortical FC was closely related with cognitive impairments in WMH patients. [ABSTRACT FROM AUTHOR]

Background: Schizotypal traits are considered as inheritable traits and the endophenotype for schizophrenia. A common variant in the NOTCH4 gene, rs204993, has been linked with schizophrenia, but the neural underpinnings are largely unknown. Methods: In present study, we compared the differences of brain functions between different genotypes of rs204993 and its relationship with schizotypal traits among 402 Chinese Han healthy volunteers. The brain function was evaluated with functional connectivity strength (FCS) using the resting-state functional magnetic resonance image(rs-fMRI). The schizotypal traits were measured by the schizotypal personality questionnaire (SPQ). Results: Our results showed that carriers with the AA genotype showed reduced FCS in the left occipital cortex when compared with carriers with the AG and GG genotypes, and the carriers with the AG genotype showed reduced FCS in the left occipital cortex when compared with carriers with the GG genotype. The FCS values in the left occipital lobe were negatively associated with the SPQ scores and its subscale scores within the carriers with the GG genotype, but not within the carriers with AA or AG genotype. Conclusion: Our results suggested that the common variant in the NOTCH4 gene, rs204993, modulates the function of the occipital cortex, which may contribute to schizotypal traits. These findings provide insight for genetic effects on schizotypal traits and its potential neural substrate. [ABSTRACT FROM AUTHOR]

Individuals with autism-like traits (ALT) belong to a subclinical group with similar social deficits as autism spectrum disorders (ASD). Their main social deficits include atypical eye contact and difficulty in understanding facial expressions, both of which are associated with an abnormality of the right posterior superior temporal sulcus (rpSTS). It is still undetermined whether it is possible to improve the social function of ALT individuals through noninvasive neural modulation. To this end, we randomly assigned ALT individuals into the real (n = 16) and sham (n = 16) stimulation groups. All subjects received five consecutive days of intermittent theta burst stimulation (iTBS) on the rpSTS. Eye tracking data and functional magnetic resonance imaging (fMRI) data were acquired on the first and sixth days. The real group showed significant improvement in emotion recognition accuracy after iTBS, but the change was not significantly larger than that in the sham group. Resting-state functional connectivity (rsFC) between the rpSTS and the left cerebellum significantly decreased in the real group than the sham group after iTBS. At baseline, rsFC in the left cerebellum was negatively correlated with emotion recognition accuracy. Our findings indicated that iTBS of the rpSTS could improve emotion perception of ALT individuals by modulating associated neural networks. This stimulation protocol could be a vital therapeutic strategy for the treatment of ASD. [ABSTRACT FROM AUTHOR]

To understand the neural mechanism of repetitive transcranial magnetic stimulation (rTMS), the after-effects following one session or multiple days of stimulation have been widely investigated. However, the relation between the short-term effect (STE) and long-term effect (LTE) of rTMS is largely unknown. This study aims to explore whether the after-effects of 5-day rTMS on supplementary motor area (SMA) network could be predicted by one-session response. A primary cohort of 38 healthy participants underwent five daily sessions of real or sham continuous theta-burst stimulation (cTBS) on the left SMA. Resting-state functional magnetic resonance imaging (fMRI) data were acquired at the first (before and after the first stimulation) and sixth experimental day. The SMA connectivity changes after the first cTBS and after 5 days of stimulation were defined as STE and LTE, respectively. Compared to the baseline, significant STE and LTE were found in the bilateral paracentral gyrus (ParaCG) after real stimulation, suggesting shared neural correlates of short- and long-term stimulations. Region-of-interest analysis indicated that the resting-state functional connectivity between SMA and ParaCG increased after real stimulation, while no significant change was found after sham stimulation. Leave-one-out cross-validation indicated that the LTE in ParaCG could be predicted by the STE after real but not sham stimulations. In an independent cohort, the after-effects of rTMS on ParaCG and short- to long-term prediction were reproduced at the region-of-interest level. These imaging evidences indicate that one-session rTMS can aid to predict the regions responsive to long-term stimulation and the individualized response degree. [ABSTRACT FROM AUTHOR]

Functional connectomes have been suggested as fingerprinting for individual identification. Accordingly, we hypothesized that subjects in the same phenotypic group have similar functional connectome features, which could help to discriminate schizophrenia (SCH) patients from healthy controls (HCs) and from depression patients. To this end, we included resting‐state functional magnetic resonance imaging data of SCH, depression patients, and HCs from three centers. We first investigated the characteristics of connectome similarity between individuals, and found higher similarity between subjects belonging to the same group (i.e., SCH–SCH) than different groups (i.e., HC–SCH). These findings suggest that the average connectome within group (termed as group‐specific functional connectome [GFC]) may help in individual classification. Consistently, significant accuracy (75–77%) and area under curve (81–86%) were found in discriminating SCH from HC or depression patients by GFC‐based leave‐one‐out cross‐validation. Cross‐center classification further suggests a good generalizability of the GFC classification. We additionally included normal aging data (255 young and 242 old subjects with different scanning sequences) to show factors could be improved for better classification performance, and the findings emphasized the importance of increasing sample size but not temporal resolution during scanning. In conclusion, our findings suggest that the average functional connectome across subjects contained group‐specific biological features and may be helpful in clinical diagnosis for schizophrenia. [ABSTRACT FROM AUTHOR]

Personalized functional connectivity mapping has been demonstrated to be promising in identifying underlying neurophysiological basis for brain disorders and treatment effects. Electroconvulsive therapy (ECT) has been proved to be an effective treatment for major depressive disorder (MDD) while its active mechanisms remain unclear. Here, 46 MDD patients before and after ECT as well as 46 demographically matched healthy controls (HC) underwent resting-state functional magnetic resonance imaging (rs-fMRI) scans. A spatially regularized form of non-negative matrix factorization (NMF) was used to accurately identify functional networks (FNs) in individuals to map individual-level static and dynamic functional network connectivity (FNC) to reveal the underlying neurophysiological basis of therepetical effects of ECT for MDD. Moreover, these static and dynamic FNCs were used as features to predict the clinical treatment outcomes for MDD patients. We found that ECT could modulate both static and dynamic large-scale FNCs at individual level in MDD patients, and dynamic FNCs were closely associated with depression and anxiety symptoms. Importantly, we found that individual FNCs, particularly the individual dynamic FNCs could better predict the treatment outcomes of ECT suggesting that dynamic functional connectivity analysis may be better to link brain functional characteristics with clinical symptoms and treatment outcomes. Taken together, our findings provide new evidence for the active mechanisms and biomarkers for ECT to improve diagnostic accuracy and to guide individual treatment selection for MDD patients. • The longitudinal MRI data for MDD patients before and after ECT were acquired. • Individual large-scale functional network for each subject was mapped. • Static and dynamic large-scale functional network connectivity analyses were employed. • Machine learning based prediction model for treatment outcome was established. [ABSTRACT FROM AUTHOR]

Inter-hemispheric cooperation is a prominent feature of the human brain, and previous neuroimaging studies have revealed aberrant inter-hemispheric cooperation patterns in patients with major depressive disorder (MDD). Typically, inter-hemispheric cooperation is examined by calculating the functional connectivity (FC) between each voxel in one hemisphere and its anatomical (structurally homotopic) counterpart in the opposite hemisphere. However, bilateral hemispheres are actually asymmetric in anatomy. In the present study, we utilized connectivity between functionally homotopic voxels (CFH) to investigate abnormal inter-hemispheric cooperation in 96 MDD patients compared to 173 age- and sex-matched healthy controls (HCs). In addition, we analyzed the spatial correlations between abnormal CFH and the density maps of 13 neurotransmitter receptors and transporters. The CFH values in bilateral orbital frontal gyri and bilateral postcentral gyri were abnormally decreased in patients with MDD. Furthermore, these CFH abnormalities were correlated with clinical symptoms. In addition, the abnormal CFH pattern in MDD patients was spatially correlated with the distribution pattern of 5-HT 1A R. drug effect; the cross-sectional research design precludes causal inferences; the neurotransmitter atlases selected were constructed from healthy individuals rather than MDD patients. These findings characterized the abnormal inter-hemispheric cooperation in MDD using a novel method and the underlying neurotransmitter mechanism, which promotes our understanding of the pathophysiology of depression. • Major depressive disorder (MDD) patients showed a decreased connectivity between functionally homotopic voxels (CFH) in the bilateral orbital frontal gyri and bilateral postcentral gyri, when compared with healthy controls. • At the molecular level, the abnormal CFH pattern in MDD patients was spatially correlated with the distribution pattern of 5-HT 1A R. • The CFH abnormalities were correlated with clinical symptoms. [ABSTRACT FROM AUTHOR]

Background: Cerebral specialization and interhemispheric cooperation are two vital features of the human brain. Their dysfunction may be associated with disease progression in patients with Alzheimer's disease (AD), which is featured as progressive cognitive degeneration and asymmetric neuropathology. Objective: This study aimed to examine and define two inherent properties of hemispheric function in patients with AD by utilizing resting‐state functional magnetic resonance imaging (rs‐fMRI). Methods: Sixty‐four clinically diagnosed AD patients and 52 age‐ and sex‐matched cognitively normal subjects were recruited and underwent MRI and clinical evaluation. We calculated and compared brain specialization (autonomy index, AI) and interhemispheric cooperation (connectivity between functionally homotopic voxels, CFH). Results: In comparison to healthy controls, patients with AD exhibited enhanced AI in the left middle occipital gyrus. This increase in specialization can be attributed to reduced functional connectivity in the contralateral region, such as the right temporal lobe. The CFH of the bilateral precuneus and prefrontal areas was significantly decreased in AD patients compared to controls. Imaging‐cognitive correlation analysis indicated that the CFH of the right prefrontal cortex was marginally positively related to the Montreal Cognitive Assessment score in patients and the Auditory Verbal Learning Test score. Moreover, taking abnormal AI and CFH values as features, support vector machine‐based classification achieved good accuracy, sensitivity, specificity, and area under the curve by leave‐one‐out cross‐validation. Conclusion: This study suggests that individuals with AD have abnormal cerebral specialization and interhemispheric cooperation. This provides new insights for further elucidation of the pathological mechanisms of AD. [ABSTRACT FROM AUTHOR]

Generalized anxiety disorder (GAD) is a highly prevalent disease characterized by chronic, pervasive, and intrusive worry. Previous resting-state functional MRI (fMRI) studies on GAD have mainly focused on conventional static linear features. Entropy analysis of resting-state functional magnetic resonance imaging (rs-fMRI) has recently been adopted to characterize brain temporal dynamics in some neuropsychological or psychiatric diseases. However, the nonlinear dynamic complexity of brain signals has been rarely explored in GAD. We measured the approximate entropy (ApEn) and sample entropy (SampEn) of the resting-state fMRI data from 38 GAD patients and 37 matched healthy controls (HCs). The brain regions with significantly different ApEn and SampEn values between the two groups were extracted. Using these brain regions as seed points, we also investigated whether there are differences in whole brain resting-state function connectivity (RSFC) pattern between GADs and HCs. Correlation analysis was subsequently conducted to investigate the association between brain entropy, RSFC and the severity of anxiety symptoms. A linear support vector machine (SVM) was used to assess the discriminative power of BEN and RSFC features among GAD patients and HCs. Compared to the HCs, patients with GAD showed increased levels of ApEn in the right angular cortex (AG) and increased levels of SampEn in the right middle occipital gyrus (MOG) as well as the right inferior occipital gyrus (IOG). Contrarily, compared to the HCs, patients with GAD showed decreased RSFC between the right AG and the right inferior parietal gyrus (IPG). The SVM-based classification model achieved 85.33 % accuracy (sensitivity: 89.19 %; specificity: 81.58 %; and area under the receiver operating characteristic curve: 0.9018). The ApEn of the right AG and the SVM-based decision value was positively correlated with the Hamilton Anxiety Scale (HAMA). This study used cross-sectional data and sample size was small. Patients with GAD showed increased level of nonlinear dynamical complexity of ApEn in the right AG and decreased linear features of RSFC in the right IPG. Combining the linear and nonlinear features of brain signals may be used to effectively diagnose psychiatric disorders. • A comprehensive analysis method, both brain entropy and RSFC analysis were adopted. • GAD patients showed increased BEN and decreased RSFC compared to HCs. • The SVM-based analysis achieved a correct classification rate of 85.33% assessing the discriminative power of GAD. • The increased BEN of the rAG and SVM-based decision value were associated with clinical response. [ABSTRACT FROM AUTHOR]

Disrupted topological organization of functional brain networks has been well documented in major depressive disorder (MDD). However, there is no report about how electroconvulsive therapy (ECT), a rapid way for depression remission, affects whole-brain functional network topological architecture to improve clinical symptoms in individuals with MDD. In this study, resting-state functional magnetic resonance imaging (rs-fMRI) data were collected for twenty-four MDD patients before and after receiving ECT and 25 gender-, age- and education-matched healthy controls (HC). The functional brain network for each subject was mapped using Brainnetome Atlas and graph-theory was applied to measure topological properties for both binary and weighted network. The results showed that ECT can significantly increase shortest path length and decrease global efficiency in MDD patients. In addition, significant alterations in nodal degree, nodal efficiency as well as between nodal functional connectivity strength were found in MDD patients after ECT. The network nodes showing changed degree, efficiency and connectivity were primarily distributed in default mode network (DMN), fronto-parietal network (FPN), and limbic system. Our findings demonstrates that ECT improves depressive symptoms by reorganizing disrupted network topological architecture in MDD patients and highlights the important role of functional reorganization of DMN, FPN, and limbic network contributing to depression remission. [ABSTRACT FROM AUTHOR]

• Decreased functional connectivity of the intralaminar and medial thalamus with the precuneus was observed in our patients, highlighting the different functions of each thalamic subdivision and different disease process for each subnucleus. • Our results suggested that dysfunction of the intralaminar and medial thalamus is instrumental in Alzheimer's disease. • Our findings could contribute to advancements in precision medicine, i.e., the fact that there is dysfunction in the functional connectivity of the intralaminar and medial thalamus with the precuneus could be considered in target-based therapy such as repetitive transcranial magnetic stimulation or deep brain stimulation. Alzheimer's disease (AD) is characterized by global cognitive impairment in multiple cognitive domains. Thalamic dysfunction during AD progression has been reported. However, there are limited studies regarding dysfunction in the functional connectivity (FC) of thalamic subdivisions and the relationship between such dysfunction and clinical assessments. This study examined dysfunction in the FC of thalamic subdivisions and determined the relationship between such dysfunction and clinical assessments. Forty-eight patients with AD and 47 matched healthy controls were recruited and assessed with scales for multiple cognitive domains. Group-wise comparisons of FC with thalamic subdivisions as seed points were conducted to identify abnormal cerebral regions. Moreover, correlation analysis was conducted to evaluate the relationship between abnormal FC and cognitive performance. Decreased FC of the intralaminar and medial nuclei with the left precuneus was observed in patients but not in heathy controls. The abnormal FC of the medial nuclei with the left precuneus was correlated with the Mini Mental State Examination score in the patient group. Using the FC values showing between-group differences, the linear support vector machine classifier achieved quite good in accuracy, sensitivity, specificity and area under the curve. Dysfunction in the FC of the intralaminar and medial thalamus with the precuneus may comprise a potential neural substrate for cognitive impairment during AD progression, which in turn may provide new treatment targets. [ABSTRACT FROM AUTHOR]

Background: Somatic anxiety patients complain of physical symptoms and exhibit repeated checking behavior. Overgeneralization of fear is a characteristic of anxiety disorders. However, the role of fear in the somatic anxiety patients remains unclear. We hypothesized that somatic anxiety patients have abnormal fear circuits, including the amygdala, hippocampus, thalamus, orbitofrontal cortex and anterior cingulate cortex, which can aggravate physical symptoms.Methods: 33 anxiety patients and 25 healthy controls (HCs) were recruited. The severity of the anxiety and somatic symptoms was assessed with the Hamilton anxiety scale and the 15-item somatic symptom severity scale from the Patient Health Questionnaire (PHQ-15). The amplitude of low-frequency fluctuations (ALFF) in resting-state functional magnetic resonance imaging was used to assess abnormalities in the fear circuit. We compared the ALFF between patients and HCs with respect to the fear circuit and conducted correlation analysis to investigate the relationship between somatic symptoms and the ALFF in abnormal cerebral regions.Results: The ALFF of the left thalamus and left hippocampus was significantly higher in the patient group than the HC group, and was positively correlated with the PHQ-15 values.Limitations: We did not divide the patient group into drug treated or drug free in our subgroup analysis. There was a lack of the paradigm to test the generalization of fear for patients in this study. Furthermore, the small sample size may have affected the results.Conclusion: Somatic symptoms in patients with anxiety are related to abnormal fear circuits, whose degree of abnormality is associated with symptom severity. [ABSTRACT FROM AUTHOR]

The right inferior frontal gyrus (rIFG) is a key cortical node in the circuits of emotion and cognitive control, and it has been frequently associated with bipolar disorder (BP); however, a reliable pattern of aberrant rIFG activation and connectivity in bipolar disorder has yet to be established. To further elucidate rIFG abnormalities in different states of bipolar disorder, we examined activation and functional connectivity (FC) in five subregions of rIFG in bipolar disorder. A total of 83 participants, including those with bipolar depression (BPD; n = 25) and bipolar mania (BPM; n = 37) along with healthy control (HC) subjects (n = 26), were examined by resting state functional magnetic resonance imaging (rs-fMRI). Both BPD and BPM groups showed higher values of amplitude of low-frequency fluctuations (ALFF) than healthy control in four of the five rIFG subregions except cluster 2(posterior-ventral rIFG). Using five subregions of rIFG as seeds, the decreased FC in bipolar disorder was mainly between posterior-ventral rIFG(cluster 2) and multiple brain regions including the postcentral gyrus, the precentral gyrus, paracentral lobule, lingual Gyrus, fusiform and cerebellum posterior lobe. These results indicated that local activity and FC were altered within specific subregions of the rIFG in BP. These findings may provide the distinct functional connectivity of rIFG subregions in BP and suggest that the cluster2 (posterior-ventral rIFG) circuitry plays a crucial role in BP. Also, such abnormalities might help define a more precise intervention targets. [ABSTRACT FROM AUTHOR]

Background: Electroconvulsive therapy (ECT) can lead to rapid and effective responses in major depressive disorder (MDD). However, the precise neural mechanisms of ECT for MDD are still unclear. Previous work has confirmed that thalamocortical circuits play an important role in emotion and cognition. However, the relationship between mechanisms of ECT for MDD and thalamocortical connectivity has not yet been investigated.Method: Thalamocortical functional connectivity analysis was performed on resting-state functional magnetic resonance imaging (fMRI) data collected from 28 MDD patients both pre- and post-ECT treatment, as well as 20 healthy controls. The cortex was parceled into six regions of interest (ROIs), which were used as seeds to assess the functional connectivity between the cortex and each voxel in the thalamus. Then, functional connectivity between the identified thalamic subregions and the rest of the brain was quantified to better localize thalamocortical connectivity related to ECT. Structural connectivity among the functionally abnormal regions was also determined using probabilistic tractography from diffusion tensor imaging (DTI) data.Results: There was decreased parietal cortex-left pulvinar and left pulvinar-bilateral precuneus functional connectivity in post-ECT MDD patients, compared to pre-ECT MDD patients. Furthermore, functional connectivity strength of parietal cortex-left pulvinar and left pulvinar-bilateral precuneus was negative correlation with verbal fluency test scores in post-ECT MDD patients. No significant change was found in structural connectivity analysis.Limitations: The sample size of our study was not large.Conclusion: Our findings implicate that the specific abnormalities in thalamocortical circuit may be associated with cognitive impairment induced by ECT. [ABSTRACT FROM AUTHOR]

Background: Electroconvulsive therapy (ECT) has been demonstrated to be an effective treatment of major depressive disorder (MDD). However, the neuroanatomical basis of response to ECT is still largely unknown.Methods: In present study, we used functional connectivity density (FCD) and resting-state functional connectivity (RSFC) to identify the relationship between the changes of resting-state activities and ECT responses in 23 MDD patients before and after ECT. In addition, the identified neural indices as classification characteristics were entered into multivariate pattern analysis using linear support vector machine (SVM) to classify 23 MDD patients before ECT from 25 gender, age and years of education matched healthy controls.Results: We found that the changes of local FCD (lFCD), not long-range FCD, of the left pre-/postcentral gyrus (Pre-/postCG), left superior temporal gyrus (STG), and right STG were significantly correlated with the changes of Hamilton Rating Scale for Depression (HRSD) scores in MDD patients before and after ECT. The subsequent functional connectivity analysis revealed significantly decreased functional connectivity between right STG and right intraparietal sulcus (IPS) in MDD after ECT in spite of no correlation with HRSD scores. Finally, SVM-based classification achieved an accuracy of 72.92% with a sensitivity of 73.91% and a specificity of 72% by leave-one-out cross-validation.Conclusions: Our findings indicated that Pre-/postCG and bilateral STG play an important role in response of ECT in MDD patients, and the lFCD in these areas may serve as a biomarker for predicting ECT response. [ABSTRACT FROM AUTHOR]

Major depressive disorder is a heterogeneous syndrome, of which the most common subtype is melancholic depression (MEL). Previous studies have indicated that anhedonia is frequently a cardinal feature in MEL. As a common syndrome of motivational deficit, anhedonia is closely associated with dysfunction in reward-related networks. However, little is currently known about apathy, another syndrome of motivational deficits, and the underlying neural mechanisms in MEL and non-melancholic depression (NMEL). Herein, the Apathy Evaluation Scale (AES) was used to compare apathy between MEL and NMEL. On the basis of resting-state functional magnetic resonance imaging, functional connectivity strength (FCS) and seed-based functional connectivity (FC) were calculated within reward-related networks and compared among 43 patients with MEL, 30 patients with NMEL, and 35 healthy controls. Patients with MEL had higher AES scores than those with NMEL (t = −2.20, P = 0.03). Relative to NMEL, MEL was associated with greater FCS (t = 4.27, P < 0.001) in the left ventral striatum (VS), and greater FC of the VS with the ventral medial prefrontal cortex (t = 5.03, P < 0.001) and dorsolateral prefrontal cortex (t = 3.18, P = 0.005). Taken together the results indicate that reward-related networks may play diverse pathophysiological roles in MEL and NMEL, thus providing potential directions for future interventions in the treatment of various depression subtypes. [ABSTRACT FROM AUTHOR]

• Significant decreases in brain dynamics were observed in the right dACC and the right precuneus in post-ECT patients compared with that of pre-ECT patients. • Significant increases in brain dynamics were observed in the bilateral mSFC in post-ECT patients compared with that of pre-ECT patients. • The dALFF of the right dACC was significantly higher in pre-ECT patients than HCs, but no significant difference between post-ECT patients and HCs. Electroconvulsive therapy (ECT) has been demonstrated to be effective in treating depressed patients. Previous neuroimaging studies have focused mainly on alterations in static brain activity and connectivity to study the effects of ECT in depressed patients. However, it remains unclear whether the temporal dynamics of brain activity are associated with mechanisms of ECT in depressed patients. We measured the dynamics of spontaneous brain activity using dynamic amplitude of low-frequency fluctuation (dALFF) in healthy controls (n = 40) and patients diagnosed with unipolar depression (UD, n = 36) or bipolar disorder (BD, n = 9) before and after ECT. Furthermore, the temporal variability of intrinsic brain activity (iBA) was quantified as the variance of dALFF across sliding window. In addition, correlation analysis was performed to investigate the relationships among dALFF, depressive symptoms, and cognitive function in depressed patients. We lack second resting-state functional magnetic resonance imaging (rs-fMRI) data for healthy controls. After ECT, patients showed decreased brain dynamics (less temporal variability) in the right dorsal anterior cingulate cortex (dACC) and the right precuneus, whereas they showed increased brain dynamics in the bilateral superior medial frontal cortex (mSFC). No significant correlation was found between the dALFF and clinical variables in depressed patients. Our findings suggest that right dACC, right precuneus, and bilateral mSFC play an important role in response to ECT depressed patients from the perspective of dynamic local brain activity, indicating that the dALFF variability may be useful in further understanding the mechanisms of ECT's antidepressant effects. [ABSTRACT FROM AUTHOR]

• Left angular gyrus plays an important role in the mechanism of electroconvulsive therapy. • Electroconvulsive therapy can increase the regional homogeneity value of the left angular gyrus. • The left inferior temporal gyrus and left posterior cingulate gyrus may be engaged in verbal memory. Electroconvulsive therapy (ECT) is a rapid and effective treatment for MDD. However, the mechanism of ECT for MDD has not been clarified. In this study, we used resting-state functional magnetic resonance imaging (rs-fMRI) to explore the mechanism of ECT. Two groups of subjects were recruited: healthy controls (HCs) and MDD patients who received bifrontal ECT. MDD patients and HCs underwent rs-fMRI scans and clinical assessments (Hamilton Depression Rating Scale, Rey-Auditory Verbal Learning Test (RAVLT), and the verbal fluency test). Regional homogeneity (ReHo) and functional connectivity were evaluated for the analysis of rs-fMRI data. The results showed that ReHo values in the left angular gyrus (LAG) significantly increased in MDD patients after ECT, and the functional connectivity of the LAG with bilateral inferior temporal gyrus, bilateral middle frontal gyrus, left superior frontal gyrus, left middle temporal gyrus, left precuneus, left posterior cingulate gyrus, and right angular gyrus was found to be strengthened after ECT. The scores of delayed recall trial in the RAVLT of MDD patients were related to the functional connectivity of the LAG with the left inferior temporal gyrus and the left posterior cingulate gyrus. It indicated LAG palyed an important role in the mechanism of ECT in MDD. [ABSTRACT FROM AUTHOR]