Left Posterior Cingulate Research Articles

Abstract 13806: Catheter Ablation Improves Quasar-Arterial Spin Labeling Based Regional Brain Perfusion in the Posterior Cingulate Cortex and Auditory-verbal Memory Function in Elderly Patients With Atrial Fibrillation

Introduction: Recent epidemiological studies suggest that atrial fibrillation (AF) is a risk factor for cognitive decline and dementia in elderly population, which may be attributable to reduced stroke volume and related brain hypoperfusion as a potential cause. Catheter ablation therapy is an option for radical cure of AF. Although several researchers mentioned the possibility to improve cognition after the intervention, specific topographic features of the brain perfusion have not been well investigated. Hypothesis: To visualize hemodynamic alteration in regional cerebra blood flow (rCBF) associated with catheter ablation therapy using noninvasive MRI voxel-based analysis method and to clarify the relationship between AF and cognitive decline. Methods: Eight patients with persistent AF (2 male, average age 63.4±7.3) underwent noninvasive brain MRI perfusion imaging with a novel dynamic model-free arterial spin-labeling (ASL) technique (quantitative STAR labeling of arterial regions [QUASAR]) and cognitive tests including Mini-Mental State Exam (MMSE) and Ray Auditory Verbal Learning Test (RAVLT) before and after 6-months of intervention. QUASAR-ASL images were spatially normalized with SPM 12 applied by partial volume correction, followed by comparison of rCBF of each brain areas with voxel-based paired-t test. Results: After the ablation therapy, QUASAR-ASL showed significantly increased rCBF in the left posterior cingulate gyrus (PCC) (FWE, P < 0.05, MNI coordinates = -9 -45 5, Figure), which was accompanied by improved scores of the RAVLT ( P < 0.001). Conclusions: The PCC is a critical part of the limbic system initially affected focal energy metabolism by Alzheimer’s disease. Improved rCBF in left PCC in patients with AF after catheter ablation therapy, as demonstrated by QUASAR-ASL method, may prevent episodic memory decline related to the auditory-verbal cognitive function.

Age and sex impact plasma NFL and t-Tau trajectories in individuals with subjective memory complaints: a 3-year follow-up study

BackgroundPlasma neurofilament light (NFL) and total Tau (t-Tau) proteins are candidate biomarkers for early stages of Alzheimer’s disease (AD). The impact of biological factors on their plasma concentrations in individuals with subjective memory complaints (SMC) has been poorly explored. We longitudinally investigate the effect of sex, age, APOE ε4 allele, comorbidities, brain amyloid-β (Aβ) burden, and cognitive scores on plasma NFL and t-Tau concentrations in cognitively healthy individuals with SMC, a condition associated with AD development.MethodsThree hundred sixteen and 79 individuals, respectively, have baseline and three-time point assessments (at baseline, 1-year, and 3-year follow-up) of the two biomarkers. Plasma biomarkers were measured with an ultrasensitive assay in a mono-center cohort (INSIGHT-preAD study).ResultsWe show an effect of age on plasma NFL, with women having a higher increase of plasma t-Tau concentrations compared to men, over time. The APOE ε4 allele does not affect the biomarker concentrations while plasma vitamin B12 deficiency is associated with higher plasma t-Tau concentrations. Both biomarkers are correlated and increase over time. Baseline NFL is related to the rate of Aβ deposition at 2-year follow-up in the left-posterior cingulate and the inferior parietal gyri. Baseline plasma NFL and the rate of change of plasma t-Tau are inversely associated with cognitive score.ConclusionWe find that plasma NFL and t-Tau longitudinal trajectories are affected by age and female sex, respectively, in SMC individuals. Exploring the influence of biological variables on AD biomarkers is crucial for their clinical validation in blood.

Identification of suicidality in adolescent major depressive disorder patients using sMRI: A machine learning approach.

Background: Suicidal behavior is a major concern for patients who suffer from major depressive disorder (MDD), especially among adolescents and young adults. Machine learning models with the capability of suicide risk identification at an individual level could improve suicide prevention among high-risk patient population.Methods: A cross-sectional assessment was conducted on a sample of 66 adolescents/young adults diagnosed with MDD. The structural T1-weighted MRI scan of each subject was processed using the FreeSurfer software. The classification model was conducted using the Support Vector Machine - Recursive Feature Elimination (SVM-RFE) algorithm to distinguish suicide attempters and patients with suicidal ideation but without attempts.Results: The SVM model was able to correctly identify suicide attempters and patients with suicidal ideation but without attempts with a cross-validated prediction balanced accuracy of 78.59%, the sensitivity was 73.17% and the specificity was 84.0%. The positive predictive value of suicide attempt was 88.24%, and the negative predictive value was 65.63%. Right lateral orbitofrontal thickness, left caudal anterior cingulate thickness, left fusiform thickness, left temporal pole volume, right rostral anterior cingulate volume, left lateral orbitofrontal thickness, left posterior cingulate thickness, right pars orbitalis thickness, right posterior cingulate thickness, and left medial orbitofrontal thickness were the 10 top-ranked classifiers for suicide attempt.Conclusions: The findings indicated that structural MRI data can be useful for the classification of suicide risk. The algorithm developed in current study may lead to identify suicide attempt risk among MDD patients.

Alterations in intrinsic functional networks in Parkinson's disease patients with depression: A resting-state functional magnetic resonance imaging study.

AimsThe aim of this research was to investigate the alterations in functional brain networks and to assess the relationship between depressive impairment and topological network changes in Parkinson's disease (PD) patients with depression (DPD).MethodsTwenty‐two DPD patients, 23 PD patients without depression (NDPD), and 25 matched healthy controls (HCs) were enrolled. All participants were examined by resting‐state functional magnetic resonance imaging scans. Graph theoretical analysis and network‐based statistic methods were used to analyze brain network topological properties and abnormal subnetworks, respectively.ResultsThe DPD group showed significantly decreased local efficiency compared with the HC group (P = .008, FDR corrected). In nodal metrics analyses, the degree of the right inferior occipital gyrus (P = .0001, FDR corrected) was positively correlated with the Hamilton Depression Rating Scale scores in the DPD group. Meanwhile, the temporal visual cortex, including the bilateral middle temporal gyri and right inferior temporal gyrus in the HC and NDPD groups and the left posterior cingulate gyrus in the NDPD group, was defined as hub region, but not in the DPD group. Compared with the HC group, the DPD group had extensive weakening of connections between the temporal‐occipital visual cortex and the prefrontal‐limbic network.ConclusionsThese results suggest that PD depression is associated with disruptions in the topological organization of functional brain networks, mainly involved the temporal‐occipital visual cortex and the posterior cingulate gyrus and may advance our current understanding of the pathophysiological mechanisms underlying DPD.

Bifrontal electroconvulsive therapy changed regional homogeneity and functional connectivity of left angular gyrus in major depressive disorder

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.

Brain structural changes in CADASIL patients: A morphometric magnetic resonance imaging study

BackgroundCerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a subcortical, inherited, cerebral small vessel disease. Several studies have revealed the involvement of specific cortical regions. However, the structural brain alterations and their clinical correlations remain largely undetermined. MethodsWe evaluated 22 CADASIL patients and 22 age- and sex-matched healthy controls. We used surface- and voxel-based morphometric data derived from 3.0-T magnetic resonance imaging (MRI) to explore structural changes in gray and white matter. We calculated Pearson correlations between such data and clinical and MRI metrics. ResultsCompared with controls, CADASIL patients exhibited significantly decreased cortical thickness in the left supramarginal gyrus, superior temporal gyrus, transverse temporal gyrus, insula, lateral orbitofrontal gyrus, isthmus cingulate gyrus and precentral gyrus. An extensive decrease in the white (but not gray) matter volume was also evident, predominantly in the frontal, parietal, temporal, and occipital lobes. The number of previous strokes or transient ischemic attacks was negatively associated with the cortical thickness of the left pars opercularis and right posterior cingulate gyrus. ConclusionReductions in cortical thickness and white matter volume were evident in CADASIL patients compared with controls, and higher numbers of strokes and transient ischemic attacks were associated with regional cortical thinning.

The changes in the topological properties of brain structural network based on diffusion tensor imaging in pediatric epilepsy patients with vagus nerve stimulators: A graph theoretical analysis

PurposeThis study aimed to analyze the topological characteristics of brain structural network in pediatric epilepsy patients with vagus nerve stimulation (VNS) by applying graph theoretical approaches. MethodsNine patients with generalized seizures and eight normal controls (NC) were enrolled. Based on diffusion tensor imaging, graph theory analysis was used to characterize the topological properties in preoperative patients (EP-pre), postoperative patients (EP-post) and NC. The global properties included clustering coefficient (Cp), shortest path length (Lp), small-worldness (γ, λ, δ), global network efficiency (Eg) and local network efficiency (Eloc). The regional properties included degree centrality (DC), nodal efficiency (NE), nodal local efficiency (NLE) and nodal shortest path length (Np). Two sample t-test and paired sample t-test were utilized to compare properties difference. ResultsAll three groups followed small-world characteristics. There was no significant difference in small-worldness, Cp, Lp, Eg or Eloc between EP-pre and EP-post. Compared with EP-pre: DC in EP-post decreased in the right cuneus and right temporal gyri, while increased in the right paracentral lobule; NE in EP-post decreased in the left dorsolateral superior frontal gyrus, right cuneus, right supramarginal gyrus, and right rolandic operculum, while increased in the right paracentral lobule; NLE in EP-post decreased in the left posterior cingulate gyrus and right supramarginal gyrus, while increased in the left parahippocampal gyrus; NP in EP-post decreased in the right paracentral lobule, while increased in the right cuneus. ConclusionVNS causes topological characteristics changes in pediatric patients with generalized seizures through regulating regional properties in some brain structures.

Altered Whole-Brain Functional Networks in Drug-Naïve, First-Episode Adolescents With Major Depression Disorder.

Neuroimaging studies have demonstrated disrupted brain functional networks in major depression disorder (MDD); however, alterations to whole-brain networks specifically associated with adolescent MDD remain poorly understood. To investigate the topological architecture of intrinsic brain functional networks in drug-naïve, first-episode adolescent MDD patients using graph theoretical analysis. Prospective. In all, 109 adolescent MDD patients and 70 healthy control subjects. 3.0T; gradient-echo echo-planar imaging sequence. After the construction of whole-brain functional networks by thresholding partial correlation matrices of 90 brain regions, we calculated the topological properties (eg, small-world, efficiency, and nodal centrality) using graph theoretical analysis. A chi-squared test was used to compare the gender-ratio difference, and a two-sample t-test was used in the comparison of age. We compared network measures between the two groups using nonparametric permutation tests. Exploratory partial correlation analyses were used to determine the relationships between the topological metrics showing significant between-group differences and the clinical variables for adolescent MDD patients. Small-world architecture in brain functional networks was identified for both the MDD and control groups. However, depressed adolescents exhibited lower characteristic path length, normalized characteristic path length and clustering coefficient, and higher global efficiency than controls (false discovery rate [FDR] q < 0.05). Compared with controls, depressed adolescents exhibited increased nodal centralities in the default mode regions, including the right anterior cingulate and paracingulate gyri, left posterior cingulate gyrus, right superior frontal gyrus (medial part), bilateral hippocampus, and bilateral parahippocampal gyrus, and decreased nodal centralities in the orbitofrontal, temporal, and occipital regions (FDR q < 0.05). This study indicated that drug-naïve, first-episode adolescent MDD patients exhibit disruptions in whole-brain functional networks. 1 TECHNICAL EFFICACY STAGE: 2 J. MAGN. RESON. IMAGING 2020;52:1790-1798.

The Use of Random Forests to Identify Brain Regions on Amyloid and FDG PET Associated With MoCA Score.

The aim of this study was to evaluate random forests (RFs) to identify ROIs on F-florbetapir and F-FDG PET associated with Montreal Cognitive Assessment (MoCA) score. Fifty-seven subjects with significant white matter disease presenting with either transient ischemic attack/lacunar stroke or mild cognitive impairment from early Alzheimer disease, enrolled in a multicenter prospective observational trial, had MoCA and F-florbetapir PET; 55 had F-FDG PET. Scans were processed using the MINC toolkit to generate SUV ratios, normalized to cerebellar gray matter (F-florbetapir PET), or pons (F-FDG PET). SUV ratio data and MoCA score were used for supervised training of RFs programmed in MATLAB. F-Florbetapir PETs were randomly divided into 40 training and 17 testing scans; 100 RFs of 1000 trees, constructed from a random subset of 16 training scans and 20 ROIs, identified ROIs associated with MoCA score: right posterior cingulate gyrus, right anterior cingulate gyrus, left precuneus, left posterior cingulate gyrus, and right precuneus. Amyloid increased with decreasing MoCA score. F-FDG PETs were randomly divided into 40 training and 15 testing scans; 100 RFs of 1000 trees, each tree constructed from a random subset of 16 training scans and 20 ROIs, identified ROIs associated with MoCA score: left fusiform gyrus, left precuneus, left posterior cingulate gyrus, right precuneus, and left middle orbitofrontal gyrus. F-FDG decreased with decreasing MoCA score. Random forests help pinpoint clinically relevant ROIs associated with MoCA score; amyloid increased and F-FDG decreased with decreasing MoCA score, most significantly in the posterior cingulate gyrus.

0761 Independent Components Analysis And Graph Theoretical Analysis In Patients With Narcolepsy

Abstract Introduction To evaluate resting state functional connectivity and topological properties of brain network in narcolepsy compared with healthy controls. Methods Resting state fMRI was performed in 26 adult narcolepsy patients and 30 matched healthy controls. MRI data was first analyzed by group independent component analysis, then a graph theoretical method was applied to evaluate topological properties within whole brain. Small-world network parameters and nodal topological properties were measured. Altered topological properties in brain areas between groups were selected as ROI-seeds, then functional connectivity among these ROI-seeds were compared between groups. Partial correlation analysis was performed to evaluate the relationship between sleepiness severity and functional connectivity or topological properties in the narcolepsy. Results 21 independent components out of 48 components were obtained. Compared with healthy controls, narcolepsy exhibited a significant decreased functional connectivity within the executive and salience network, while increased functional connectivity in bilateral frontal lobe within executive network can be detected in narcolepsy. There were no differences in small-world network properties between narcolepsy and healthy controls. The altered brain areas in nodal topological properties were mainly located in inferior frontal cortex, basal ganglia, anterior cingulate, sensory cortex, supplementary motor cortex and visual cortex between groups. In the partial correlation analysis, nodal topological properties in putamen, anterior cingulate and sensory cortex as well as functional connectivity between these brain regions were correlated with the severity of sleepiness (sleep latency, REM sleep latency and ESS) among narcolepsy. Conclusion Altered connectivity within executive network and salience network were found in narcolepsy. Functional connection changes between left frontal cortex and left caudate nucleus may be one of the parameters describing the severity of narcolepsy. Nodal topological properties alterations in left putamen and left posterior cingulate, changes in functional connectivity between left supplementary motor area and right occipital as well as changes in functional connectivity between left anterior cingulate gyrus and bilateral postcentral gyrus can be considered to be a specific indicator for evaluating the severity of narcolepsy. Support National Natural Science Foundation of China (81700088)National Program on Key Basic Research Project of China (973 Program, 2015CB856405)

Cultural factors related to neuropsychological performance and brain atrophy among Hispanic older adults with amnestic Mild Cognitive Impairment (aMCI): A pilot study

Objectives This study examined the association of cultural factors and literacy to neuropsychological performance and measures of regional brain atrophy among Hispanic elders diagnosed with amnestic Mild Cognitive Impairment (aMCI). Method Acculturation and literacy levels were measured among 45 subjects tested in Spanish; their primary language. Scores for measures of memory, executive functioning, and verbal fluency, as well as volumetric analysis of MRI scans of left hemisphere structures commonly affected by Alzheimer’s disease (AD) were examined. Linear regression models were employed to examine the association of acculturation and literacy to neuropsychological performance and MRI measures. Results After controlling for age, higher literacy levels were associated with better performance on phonemic verbal fluency (r = 0.300, p < .05), while higher levels of acculturation to the U.S. was associated with poorer performance on category verbal fluency (r = 0.300, p < .05). There was a significant inverse relationship after controlling for age between literacy and the left entorhinal cortex (r = –0.455, p < .05), left precuneus (r = –0.457, p < .05), and left posterior cingulate (r = –0.415, p < .05). Conclusions Results of the current pilot study indicate that high acculturation to the U.S. among aMCI immigrants from Latin-American countries may hinder performance on verbal learning measures when they are administered in one’s primary language. Moreover, in this cohort, a higher literacy level, which is indicative of greater cognitive reserve, was associated with better performance in language measures, but with greater atrophy in brain regions susceptible to neurodegenerative disease. These preliminary findings should be further examined among larger cohorts and using more diverse measures, which capture other cultural constructs.

A preliminary study to investigate resting state fMRI as a potential group differentiator for schizophrenia.

Schizophrenia (SZ) is found to be associated with dysconnectivity between the various regions of the brain. These aberrant connections in brain networks responsible for various mental processes in schizophrenia. We examined differences in functional connectivity among persons with SZ (n = 30) and an equal number of their unaffected relatives using resting state functional Magnetic Resonance Imaging (rsfMRI). Subjects were interviewed using the Diagnostic Interview for Genetic Studies (DIGS) and Family Interview for Genetic Studies (FIGS). Cognition was assessed using the Computerized Neuropsychological Battery (CNB) and Trail Making Tests A and B. The resting state functional data were acquired using 3.0 T Magnetic Resonance Imaging system and analysed using Statistical Package for the Social Sciences (SPSS) version 21 and FSL version 5.01 (FMRIB's) Software. The persons with SZ performed significantly worse on tasks of cognition and executive functioning. On rsfMRI, a significantly reduced connectivity was noted in the case group in right and left precentral gyri, right post central gyrus, right and left middle temporal gyrus, left paracingulate gyrus, anterior and posterior cingulate, right planum temporale, right pallidum, left cerebellum-6,7b and 8 lobules. Increased connectivity was noted between areas of right temporal pole and left hippocampus, posterior cingulate and the precuneus, right planum polare and right amygdala, right Heschl's gyrus and left posterior supramarginal gyrus, right amygdala with right insular cortex and left cerebellum 6 with bilateral postcentral gyrus in the same group. These differences in connectivity could be utilised as potential group differentiator for schizophrenia.

Serum FAM19A5 levels: A novel biomarker for neuroinflammation and neurodegeneration in major depressive disorder

Chronic low-grade inflammation contributes to the pathophysiology of major depressive disorder (MDD). This study aimed to examine the association between serum levels of FAM19A5, a novel chemokine-like peptide that reflects reactive astrogliosis and inflammatory activation in the brain, and the neurodegenerative changes of MDD by investigating the correlation between serum FAM19A5 levels and cortical thickness changes in patients with MDD. We included 52 drug-naïve patients with MDD and 60 healthy controls (HCs). Serum FAM19A5 levels were determined in peripheral venous blood samples using a sandwich enzyme-linked immunosorbent assay. All participants underwent T1-weighted structural magnetic resonance imaging. Serum FAM19A5 levels were greater in patients with MDD than in HCs. In the MDD group, there were significant inverse correlations between serum FAM19A5 levels and cortical thickness in the prefrontal regions (i.e., the left inferior and right medial superior frontal gyri), left posterior cingulate gyrus, right cuneus, and both precunei, which showed significantly reduced thickness in patients with MDD compared to HCs. However, no correlation between serum FAM19A5 level and cortical thickness was observed in the HC group. The results of our study indicate that serum FAM19A5 levels may reflect reactive astrogliosis and related neuroinflammation in MDD. Our findings also suggest that serum FAM19A5 may be a potential biomarker for the neurodegenerative changes of MDD.

The cerebellum is associated with 2-year prognosis in patients with high-frequency migraine

BackgroundThe increase of headache frequency is associated with higher headache related disability and lower quality of life in patients with migraine. However, the pathophysiology of migraine progression, persistence, or remission is elusive. The purpose of this study is to identify the brain signatures that are predictive of the long-term outcomes among patients with high-frequency migraine (HFM: 10–30 headache days/month).MethodsWe prospectively enrolled patients with HFM and healthy controls and collected their baseline clinical profiles and brain-MRI data at first visit. We longitudinally followed the patients and determined their outcomes at 2-year follow-up. Good outcome was defined as ≥50% reduction of baseline headache days and poor outcome was defined as reduction < 50% or frequency increase. Voxel-based morphometry was used to study gray matter volume (GMV), and structural covariance was used to investigate structural connectivity.ResultsAmong 56 patients with HFM, 37 had good outcome and 19 poor outcome. Compared to the healthy controls (n = 37), patients with poor outcome had decreased GMV over the left posterior cingulate gyrus, and increased GMV over the bilateral cerebellum and the right precentral gyrus. Further, patients with poor outcome had greater GMV over the right and the left cerebella compared to patients with good outcome, and the GMVs of the cerebella were correlated to 2-year headache frequencies (right: r = 0.38, P = 0.005; left: r = 0.35, P = 0.009). Structural connectivity were increased between the cerebellum and the cuneus, the calcarine cortex, and the temporal lobe, respectively, in patients with poor outcome, and was decreased between the cerebellum and the prefrontal cortex in patients with poor outcome. The structural covariance integrities between the right cerebellum and the right cuneus were correlated to 2-year headache frequencies (r = 0.36, P = 0.008).ConclusionsStructural volume and connectivity changes of the cerebellum may underlie headache persistence in patients with HFM.

The role of altered brain structural connectivity in resilience, vulnerability, and disease expression to schizophrenia

BackgroundSchizophrenia (SCZ) is a highly heritable disorder associated with brain connectivity changes. Although the mechanism of disease expression and vulnerability of SCZ have been reported by previous studies, the mechanism of resilience to SCZ based on the brain structural connectivity is poorly understood. The goal of the present study was to identify the structural brain connectivity related with the resilience to SCZ, which is defined here as the capacity to avoid or delay the onset of SCZ in unaffected siblings of SCZ probands. MethodWe collected diffusion tensor imaging (DTI) data of 49 medication-naive, first-episode SCZ (FE-SCZ) patients, 56 unaffected siblings of SCZ probands (SIB-SCZ), and 90 healthy controls. Then we used graph theoretical approach to calculate the topological properties of the brain structural network, including global, subnetwork, and regional parameters. Finally, we compared the parameters between the three groups, and identified the brain structural network related to the resilience, vulnerability and disease expression to SCZ. ResultsWith respect to resilience, only the SIB-SCZ showed significantly increased connectivity in the subnetworks of the left cuneus-precuneus and left posterior cingulate gyrus–precuneus, and in brain areas of right supramarginal gyrus and right inferior temporal gyrus. With respect to vulnerability, both the FE-SCZ and SIB-SCZ had decreased cluster coefficients and local efficiency, and decreased nodal efficiency in the right medial superior frontal gyrus and right medial orbital superior frontal gyrus compared with the healthy controls. With respect to disease expression, only the FE-SCZ group showed decreased or increased global, subnetwork, and nodal connectivity in broader brain regions compared with the healthy controls. ConclusionDifference in the topological properties of brain structural connectivity not only reflect the underlying mechanism of vulnerability but also that of resilience to schizophrenia. Alteration in the brain structural connectivity associating with resilience and disease expression may contribute to the onset of SCZ.

Parietal memory network and default mode network in first-episode drug-naïve schizophrenia: Associations with auditory hallucination.

Atypical spontaneous activities in resting‐state networks may play a role in auditory hallucinations (AHs), but networks relevant to AHs are not apparent. Given the debating role of the default mode network (DMN) in AHs, a parietal memory network (PMN) may better echo cognitive theories of AHs in schizophrenia, because PMN is spatially adjacent to the DMN and more relevant to memory processing or information integration. To examine whether PMN is more relevant to AHs than DMN, we characterized these intrinsic networks in AHs with 59 first‐episode, drug‐naïve schizophrenics (26 AH+ and 33 AH−) and 60 healthy participants in resting‐state fMRI. We separated the PMN, DMN, and auditory network (AN) using independent component analysis, and compared their functional connectivity across the three groups. We found that only AH+ patients displayed dysconnectivity in PMN, both AH+ and AH− patients exhibited dysfunctions of AN, but neither patient group showed abnormal connectivity within DMN. The connectivity of PMN significantly correlated with memory performance of the patients. Further region‐of‐interest analyses confirmed that the connectivity between the core regions of PMN, the left posterior cingulate gyrus and the left precuneus, was significantly lower only in the AH+ group. In exploratory correlation analysis, this functional connectivity metric significantly correlated with the severity of AH symptoms. The results implicate that compared to the DMN, the PMN is more relevant to the AH symptoms in schizophrenia, and further provides a more precise potential brain modulation target for the intervention of AH symptoms.

What’s in a Hub?—Representing Identity in Language and Mathematics

Hubs emerge in structural and resting state network analysis as areas highly connected to other parts of the brain and have been shown to respond to several task domains in functional imaging studies. A cognitive explanation for this multi-functionality is still wanting. We propose, that hubs subserve domain-general meta-cognitive functions, relevant to a variety of domain-specific networks and test this hypothesis for the example of processing explicit identity information. To isolate this meta-cognitive function from the processing of domain-specific context, we investigate the overlapping activations to linguistic identity processes (e.g. Mr. Dietrich is the dentist) on the one hand and numerical identity processes (e.g. do “3 × 8” and “36–12” give the same number) on the other hand. The main question was, whether these overlapping activations would fall within areas, consistently identified as hubs by network-based analyses. Indeed, the two contrasts showed significant conjunctions in the left inferior parietal lobe (IPL), precuneus (PC), and posterior cingulate. Accordingly, identity processing may well be one domain-general meta-cognitive function that hub-areas provide to domain-specific networks. For the parietal lobe we back up our hypothesis further with existing reports of activation peaks for other tasks that depend on identity processing, e.g., episodic recollection, theory of mind, and visual perspective taking.

Differential neurocognitive network perturbation in amnestic and aphasic Alzheimer disease.

To determine if Alzheimer disease (AD) is associated with aphasic rather than amnestic dementias in certain circumstances related in part to perturbations in different networks. Three groups were investigated: 14 participants suspected of having the neuropathology of AD based on clinically diagnosed amnestic dementia of the Alzheimer type (DAT), 26 individuals with primary progressive aphasia (PPA) with either a positive 18F-florbetapir amyloid PET scan or confirmed AD at autopsy, and 26 neurologically intact controls. The groups were compared using rs-fMRI. Seeds included the left hemisphere inferior frontal gyrus (IFG) for the language network, the left hippocampus for the episodic memory network, and the left posterior cingulate for the default mode network (DMN). Greater connectivity perturbations were found from the hippocampus for the DAT group and from the IFG for the PPA group. Furthermore, connectivity alterations in the PPA group were more asymmetric and favored the language-dominant left hemisphere. Loss of connectivity from the DMN seed was of a similar magnitude in the PPA and DAT groups. Despite the presumptive common underlying neuropathology of amyloid plaques and neurofibrillary tangles, the 2 groups displayed 2 different patterns of network perturbation, each concordant with the clinical presentation and the anatomy of neurodegeneration.

Spatial Network Connectivity and Spatial Reasoning Ability in Children with Nonverbal Learning Disability

Nonverbal Learning Disability (NVLD) is characterized by deficits in visual-spatial, but not verbal, reasoning. Nevertheless, the functioning of the neural circuits supporting spatial processing have yet to be assessed in children with NVLD. We compared the resting state functional connectivity of a spatial brain network among children with NVLD, children with reading disorder (RD), and typically developing (TD) children. Seventy-five participants (7–15 years old) were included in the study (20 TD, 24 NVLD, and 31 RD). Group differences in global efficiency and functional connectivity among 12 regions comprising a previously defined spatial network were evaluated. Associations with behavior were explored. Global efficiency of the spatial network associated positively with spatial ability and inversely with socioemotional problems. Within the spatial network, associations between left posterior cingulate (PCC) and right retrosplenial cortical activity were reduced in children with NVLD relative to those without spatial deficits (RD and TD). Connectivity between left PCC and right posterior cerebellum (Crus I and II) was reduced in both groups of children with learning disabilities (NVLD and RD) relative to TD children. Functional connectivity of the spatial network was atypically associated with cognitive and socioemotional performance in children with NVLD. Identifying a neurobiological substrate for NVLD provides evidence that it is a discrete clinical entity and suggests targets for treatment.

An MRI Study of the Relationship Between Duration of Untreated Psychosis and Morphology of Cerebral Cortex in First-episode Schizophrenia

We analyzed the brain structure of schizophrenia patients from multiple perspectives to explore the relationship between the duration of untreated psychosis (DUP) and clinical outcomes. For 85 patients and 86 controls, clinical symptoms and cognitive function were evaluated, magnetic resonance imaging (MRI) and free surfer analysis were used to extract the cortical indicator, such as brain cortex thickness, surface area, volume, and so on. The patients were divided into four subgroups according to the boundary of March, June and two year due to the distribution and median of DUP. Finally multi-group comparison and correlation analysis for above indicators were analysed. DUP was associated with the surface area of the left insula, parsorbitalis, right hippocampus, superior frontal gyrus, frontal pole, and temporal pole; DUP mainly influenced the cortical thickness of left posterior cingulate gyrus, postcentral gyrus, right lateral occipital cortex, parsopercularis, medial orbitofrontal cortex, and the bilateral precentral gyrus. For cortical volume, DUP significantly affected left postcentral gyrus, right precuneus, lateral occipital cortex, parsopercularis, lingual gyrus, superior temporal gyrus, bilateral cuneus, pericalcarine cortex, precentral gyrus,superior parietal lobule, and insula.The first three months after onset is a critical period for the deterioration of cortical morphology and clinical function. DUP in first-episode schizophrenia is associated with cortical morphological changes of temporal lobe, precentral, orbitofrontal cortex and the majority of medial regions of occipital lobe, it is very important to conduct early intervention for patients.