ABSTRACT
BackgroundCompared with adult-onset schizophrenia， patients with adolescent-onset schizophrenia experience a high genetic susceptibility， severe negative symptoms， high recurrence rate， poor prognosis and social function recovery. And clarifying the brain functional alterations in adolescent-onset schizophrenia is of great significance for further elucidating the pathogenesis of the disease and exploring personalized and precise treatment. ObjectiveTo investigate the altered functional and effective connectivity of bilateral precuneus in first-episode patients with adolescent-onset schizophrenia based on resting-state functional magnetic resonance imaging （rs-fMRI）， thus providing reliable imaging evidence in guiding the study on mechanism involved in adolescent-onset schizophrenia. MethodsTwenty-one drugnaïve first-episode patients with adolescent-onset schizophrenia who met the Diagnostic and Statistical Manual of Mental Disorders， fifth edition （DSM-5） criteria for schizophrenia were enrolled， and another 21 psychiatrially healthy controls matched on age， educational background and gender were concurrently selected. The schizophrenic subjects were evaluated using the Psychotic Symptom Rating Scales （PSYRATS） and Positive and Negative Symptom Scale （PANSS）. All participants underwent rs-fMRI scans， and the whole-brain seed-based functional and effective connectivity analyses were conducted in bilateral cuneus region. Then the correlation between functional connectivity strength and clinical symptoms of patients was discussed. ResultsIn terms of functional connectivity， the functional connectivity of bilateral precuneus and left middle temporal gyrus was increased in patient group compared with healthy control group ［P<0.01， family-wise error （FWE） correction at cluster level， P<0.05］. In terms of effective connectivity， patient group responded to negative feedback with greater activation of seed region and left middle frontal gyrus than healthy control group. Correlation analysis within patient group denoted that the decreased effective connectivity of bilateral precuneus and left middle frontal gyrus was positively correlated with the total PANSS score （r=0.450， P<0.05）. ConclusionThe resting-state functional and effective connectivity of bilateral precuneus is abnormally alerted in drugnaïve first-episode patients with adolescent-onset schizophrenia， and the decreased effective connectivity of bilateral precuneus and left middle frontal gyrus may be related to the development of clinical symptoms. ［Funded by National Key Research and Development Program of China （number， 2022YFC2009901， 2022YFC2009900）］
ABSTRACT
Objective: To explore the changes of resting-state functional connectivity (FC) of bilateral precuneus and other brain regions in patients with minimal hepatic encephalopathy (MHE). Methods: Twenty-two liver cirrhosis patients with MHE (MHE group), 23 liver cirrhotic patients without MHE (NMHE group) and 24 healthy subjects (control group) underwent resting-state functional MRI (rs-fMRI). Bilateral precuneus was picked as seeds, and then FC of bilateral precuneus and other brain regions were calculated for statistical analysis by using standard seed-based whole-brain correlation method. Results: Compared with control group, the left precuneus showed reduced FC with the right superior frontal gyrus, left middle cingulate gyrus, while the right precuneus showed reduced FC with the right temporal pole, left superior temporal gyrus, bilateral frontal lobe and medial cingulum cortex in MHE group, and the left precuneus showed reduced FC with the right middle frontal gyrus, while the right precuneus showed reduced FC with the left precuneus and left middle cingulate gyrus in NMHE group (all P<0.05). Compared with the NMHE group, the left precuneus showed reduced FC with the right superior frontal gyrus, while the right precuneus showed reduced FC with the right insula and right superior/middle frontal gyrus in MHE group (all P<0.05). Conclusion: Abnormal resting-state FC of bilateral precuneus and multiple brain regions are demonstrated in patients with MHE, which may be the mechanism of endogenous neurological impairment of MHE.
ABSTRACT
Objective To investigate the changed brain areas of functional connectivity ( FC ) patterns of subthalamic nucleus ( STN) between different subtypes of Parkinson′s disease ( PD) and healthy controls and their clinical significance .Methods Twenty-three PD patients and 12 health controls were enrolled, and PD patients were divided into 11 tremor dominant PD patients and 12 postural instability and gait disorder (PIGD) dominant PD patients.The difference of whole-brain resting-state FC with STN among the three groups was investigated and the relationship between the changed areas and clinical symptoms was calculated.Results Compared with healthy controls , PIGD dominant group showed increased FC between STN and right calcarine and decreased FC between STN and right precuneus , and tremor dominant PD patients showed decreased FC between STN and precuneus , right angular gyrus and left middle frontal gyrus , while the FC strength between the STN and left middle frontal gyrus showed positive relationship with MMSE scores ( r=0.64, P=0.034 ) .Compared with tremor dominant PD patients , PIGD dominant patients showed increased FC in the area of left calcarine .Conclusions Decreased FC between STN and precuneus was gained in different subtypes of PD , and PIGD dominant patients showed increased FC between STN and calcarine.Changed areas based on the FC of STN in different subtypes of PD were found related with cognition and mood control .
ABSTRACT
OBJECTIVES: People at ultra-high risk for psychosis have heterogenous character and different long-term outcomes. We divided ultra-high risk subjects into two subgroups by presence of familial history and tried to find different pattern of functional connectivity of the default mode network (DMN) between the two groups in order to examine the effects familial loading. METHODS: Eleven subjects at clinical-high risk (CHR) group with familial history of psychiatric illness and nineteen subjects of CHR group without familial history were recruited. All the subjects were scanned using resting-state functional magnetic resonance imaging. A posterior cingulate cortex was the seed region of the analysis, and the DMN of the both high risk group were analyzed with voxel-wise two sample T test. RESULTS: The CHR group with familial history showed greater functional connectivity in the precuneus area in contrast with the other high risk subjects (peak-level t=5.49, p<0.001). There were no significant differences in total score on the Positive and Negative Syndrome Scale and Scales of Psychosis-risk Syndrome between the two groups. CONCLUSION: The study suggests that the abnormalities of functional connectivity between precuneus and posterior cingulate area may be associated with the genetic vulnerability of high risk trait.
Subject(s)
Gyrus Cinguli , Magnetic Resonance Imaging , Pilot Projects , Psychotic Disorders , Seeds , Weights and MeasuresABSTRACT
BACKGROUND AND PURPOSE: Alzheimer's disease (AD) is associated with structural alterations in the medial temporal lobe (MTL) and functional alterations in the posterior cortical region, especially in the early stages. However, it is unclear what mechanisms underlie these regional discrepancies or whether the posterior cortical hypometabolism reflects disconnection from the MTL lesion or is the result of local pathology. The precuneus, an area of the posteromedial cortex that is involved in the early stages of AD, has recently received a great deal of attention in functional neuroimaging studies. To assess the relationship between the precuneus and hippocampus in AD, we investigated the volumes of these two areas using a magnetic resonance volumetric method. METHODS: Twenty-three subjects with AD and 14 healthy age-matched controls underwent T1-weighted three-dimensional volumetric brain magnetic resonance imaging. Volumetric measurements were performed in the precuneus and hippocampus. RESULTS: Compared to controls, AD patients exhibited a significant reduction in total precuneal volume, which was more prominent on the right side, and significant bilateral reductions in hippocampal volume. No correlation was found between the total volumes of the precuneus and hippocampus in the AD group. CONCLUSIONS: These results suggest that volumetric measurements of both the precuneus and hippocampus are useful radiological indices for the diagnosis of AD. Furthermore, the lack of correlation is attributable to local pathology rather than being a secondary consequence of MTL pathology.
Subject(s)
Humans , Alzheimer Disease , Brain , Functional Neuroimaging , Hippocampus , Magnetic Resonance Imaging , Magnetic Resonance Spectroscopy , Magnetics , Magnets , Temporal LobeABSTRACT
BACKGROUND AND PURPOSE: Alzheimer's disease (AD) is associated with structural alterations in the medial temporal lobe (MTL) and functional alterations in the posterior cortical region, especially in the early stages. However, it is unclear what mechanisms underlie these regional discrepancies or whether the posterior cortical hypometabolism reflects disconnection from the MTL lesion or is the result of local pathology. The precuneus, an area of the posteromedial cortex that is involved in the early stages of AD, has recently received a great deal of attention in functional neuroimaging studies. To assess the relationship between the precuneus and hippocampus in AD, we investigated the volumes of these two areas using a magnetic resonance volumetric method. METHODS: Twenty-three subjects with AD and 14 healthy age-matched controls underwent T1-weighted three-dimensional volumetric brain magnetic resonance imaging. Volumetric measurements were performed in the precuneus and hippocampus. RESULTS: Compared to controls, AD patients exhibited a significant reduction in total precuneal volume, which was more prominent on the right side, and significant bilateral reductions in hippocampal volume. No correlation was found between the total volumes of the precuneus and hippocampus in the AD group. CONCLUSIONS: These results suggest that volumetric measurements of both the precuneus and hippocampus are useful radiological indices for the diagnosis of AD. Furthermore, the lack of correlation is attributable to local pathology rather than being a secondary consequence of MTL pathology.