Alzheimer's disease (AD) is a neurodegenerative disorder that prominently affects cerebral connectivity. Assessing the functional connectivity at rest, recent functional MRI (fMRI) studies reported on the existence of resting-state networks (RSNs). RSNs are characterized by spatially coherent, spontaneous fluctuations in the blood oxygen level-dependent signal and are made up of regional patterns commonly involved in functions such as sensory, attention, or default mode processing. In AD, the default mode network (DMN) is affected by reduced functional connectivity and atrophy. In this work, we analyzed functional and structural MRI data from healthy elderly (n ‫؍‬ 16) and patients with amnestic mild cognitive impairment (aMCI) (n ‫؍‬ 24), a syndrome of high risk for developing AD. Two questions were addressed: (i) Are any RSNs altered in aMCI? (ii) Do changes in functional connectivity relate to possible structural changes? Independent component analysis of restingstate fMRI data identified eight spatially consistent RSNs. Only selected areas of the DMN and the executive attention network demonstrated reduced network-related activity in the patient group. Voxel-based morphometry revealed atrophy in both medial temporal lobes (MTL) of the patients. The functional connectivity between both hippocampi in the MTLs and the posterior cingulate of the DMN was present in healthy controls but absent in patients. We conclude that in individuals at risk for AD, a specific subset of RSNs is altered, likely representing effects of ongoing early neurodegeneration. We interpret our finding as a proof of principle, demonstrating that functional brain disorders can be characterized by functional-disconnectivity profiles of RSNs.default mode network ͉ intrinsic brain activity ͉ mild cognitive impairment A lzheimer's disease (AD) is a neurodegenerative disorder clinically characterized by progressive dementia and neuropsychiatric symptoms (1). AD is neuropathologically defined by tau pathology and amyloid aggregations (2). Tau pathology starts in regions of the medial temporal lobe (MTL) and is well correlated with cell loss and atrophy; amyloid deposition primarily affects distributed neocortical regions but is not especially prominent in the MTL (2, 3). Atrophy of the MTL is correlated with the degree of dementia and also the extent of temporoparietal hypometabolism; both results are assumed to reflect changes in cerebral connectivity, especially between the MTL and the neocortex (3-5). In non-human primates, prominent structural connectivity between the MTL and neocortical regions as well as broad neocortical hypometabolism after ablation of parts of the MTL were demonstrated (6, 7). Evidence for disrupted structural and functional connectivity (FC) further suggests that AD includes a disconnection syndrome (5, 8-10).Mild cognitive impairment (MCI) is a syndrome with cognitive decline greater than expected for an individual's age and educational level but not interfering notably with activities of daily living; prevalence of M...

The betaA4 peptide, a major component of senile plaques in Alzheimer's disease (AD) brain, has been found in cerebrospinal fluid (CSF) and blood of both AD patients and normal subjects. Although betaA4 1-40 is the major form produced by cell metabolism and found in CSF, recent observations suggest that the long-tailed betaA4 1-42 plays a more crucial role in AD pathogenesis. Here, we established new monoclonal antibodies against the C-terminal end of betaA4 1-40 and 1-42, and used them for the specific Western blot detection. After optimizing the assay conditions, these antibodies detected low picogram amount of betaA4, and both betaA4 1-40 and 1-42 levels in CSF could be determined by direct loading of the samples. Blood levels of betaA4 1-40 and 1-42 were also determined by specific immunoprecipitation followed by Western blot detection. We found that CSF betaA4 1-42 level is lower in AD patients compared with non-demented controls, although there was a significant overlap between the groups. The level of betaA4 1-40 in CSF, and of betaA4 1-40 as well as betaA4 1-42 in plasma, were not different between AD patients and controls. Besides the 4-kDa full-length betaA4 band, we could also detect several N-terminal variants of betaA4 in CSF and plasma of both AD patients and controls. Two N-terminally truncated betaA4 species migrating at the position of 3.3 and 3.7 kDa were found in CSF, while 3.7- and 5-kDa forms were found in plasma. The relative abundance of these various species were considerably different in the CSF and plasma, suggesting that the cellular source and/or clearance of betaA4 is different in these two compartments.

In schizophrenia, consistent structural and functional changes have been demonstrated for the insula including aberrant salience processing, which is critical for psychosis. Interactions within and across default mode and central executive network (DMN, CEN) are impaired in schizophrenia. The question arises whether these 2 types of changes are related. Recently, the anterior insula has been demonstrated to control DMN/CEN interactions. We hypothesized that aberrant insula and DMN/CEN activity in schizophrenia is associated with an impaired dependence of DMN/CEN interactions on anterior insular salience network (SN) activity. Eighteen patients with schizophrenia during psychosis and 20 healthy controls were studied by resting-state-fMRI and psychometric examination. High-model-order independent component analysis of fMRI data revealed spatiotemporal patterns of synchronized ongoing blood-oxygenation-level-dependent (BOLD) activity including SN, DMN, and CEN. Scores of functional and time-lagged connectivity across networks' time courses were calculated. Connectivity scores and spatial network maps were compared between groups and related with patients' hallucination and delusion severity. Spatial BOLD-synchronicity was altered in patients' SN, DMN, and CEN, including decreased activity in the right anterior insula (rAI). Patients' functional connectivity between DMN and CEN was increased and related with hallucinations severity. Importantly, patients' time-lagged connectivity between SN and DMN/CEN was reduced, and decreased rAI activity of the SN was associated with both hallucinations and increased functional connectivity between DMN and CEN. Data provide evidence for an aberrant dependence of DMN/CEN interactions on anterior insular SN activity, linking impaired insula, DMN, CEN activity, and psychosis in schizophrenia.

Major depressive disorder (MDD) is characterized by altered intrinsic functional connectivity within (intra-iFC) intrinsic connectivity networks (ICNs), such as the Default Mode- (DMN), Salience- (SN) and Central Executive Network (CEN). It has been proposed that aberrant switching between DMN-mediated self-referential and CEN-mediated goal-directed cognitive processes might contribute to MDD, possibly explaining patients' difficulties to disengage the processing of self-focused, often negatively biased thoughts. Recently, it has been shown that the right anterior insula (rAI) within the SN is modulating DMN/CEN interactions. Since structural and functional alterations within the AI have been frequently reported in MDD, we hypothesized that aberrant intra-iFC in the SN's rAI is associated with both aberrant iFC between DMN and CEN (inter-iFC) and severity of symptoms in MDD. Twenty-five patients with MDD and 25 healthy controls were assessed using resting-state fMRI (rs-fMRI) and psychometric examination. High-model-order independent component analysis (ICA) of rs-fMRI data was performed to identify ICNs including DMN, SN, and CEN. Intra-iFC within and inter-iFC between distinct subsystems of the DMN, SN, and CEN were calculated, compared between groups and correlated with the severity of symptoms. Patients with MDD showed (1) decreased intra-iFC within the SN's rAI, (2) decreased inter-iFC between the DMN and CEN, and (3) increased inter-iFC between the SN and DMN. Moreover, decreased intra-iFC in the SN's rAI was associated with severity of symptoms and aberrant DMN/CEN interactions, with the latter losing significance after correction for multiple comparisons. Our results provide evidence for a relationship between aberrant intra-iFC in the salience network's rAI, aberrant DMN/CEN interactions and severity of symptoms, suggesting a link between aberrant salience mapping, abnormal coordination of DMN/CEN based cognitive processes and psychopathology in MDD.

IMPORTANCEThere is debate about the effectiveness of psychiatric treatments and whether pharmacotherapy or psychotherapy should be primarily used.OBJECTIVES To perform a systematic overview on the efficacy of pharmacotherapies and psychotherapies for major psychiatric disorders and to compare the quality of pharmacotherapy and psychotherapy trials. EVIDENCE REVIEWWe searched MEDLINE, EMBASE, PsycINFO, and the Cochrane Library (April 2012, with no time or language limit) for systematic reviews on pharmacotherapy or psychotherapy vs placebo, pharmacotherapy vs psychotherapy, and their combination vs either modality alone. Two reviewers independently selected the meta-analyses and extracted efficacy effect sizes. We assessed the quality of the individual trials included in the pharmacotherapy and psychotherapy meta-analyses with the Cochrane risk of bias tool.FINDINGS The search yielded 45 233 results. We included 61 meta-analyses on 21 psychiatric disorders, which contained 852 individual trials and 137 126 participants. The mean effect size of the meta-analyses was medium (mean, 0.50; 95% CI, 0.41-0.59). Effect sizes of psychotherapies vs placebo tended to be higher than those of medication, but direct comparisons, albeit usually based on few trials, did not reveal consistent differences. Individual pharmacotherapy trials were more likely to have large sample sizes, blinding, control groups, and intention-to-treat analyses. In contrast, psychotherapy trials had lower dropout rates and provided follow-up data. In psychotherapy studies, wait-list designs showed larger effects than did comparisons with placebo.CONCLUSIONS AND RELEVANCE Many pharmacotherapies and psychotherapies are effective, but there is a lot of room for improvement. Because of the multiple differences in the methods used in pharmacotherapy and psychotherapy trials, indirect comparisons of their effect sizes compared with placebo or no treatment are problematic. Well-designed direct comparisons, which are scarce, need public funding. Because patients often benefit from both forms of therapy, research should also focus on how both modalities can be best combined to maximize synergy rather than debate the use of one treatment over the other.

Alzheimer's disease (AD) is associated with defects of synaptic connectivity. Such defects may not be restricted to local neuronal interactions but may extend to long-range brain activities, such as slow-wave oscillations that are particularly prominent during non-rapid eye movement (non-REM) sleep and are important for integration of information across distant brain regions involved in memory consolidation. There is increasing evidence that sleep is often impaired in AD, but it is unclear whether this impairment is directly related to amyloid-β (Aβ) pathology. Here we demonstrate that slow-wave activity is severely altered in the neocortex, thalamus and hippocampus in mouse models of AD amyloidosis. Most notably, our results reveal an Aβ-dependent impairment of slow-wave propagation, which causes a breakdown of the characteristic long-range coherence of slow-wave activity. The finding that the impairment can be rescued by enhancing GABAAergic inhibition identifies a synaptic mechanism underlying Aβ-dependent large-scale circuit dysfunction.

Background: Chronic kidney disease (CKD) has emerged as a possible new risk factor of cognitive impairment and dementia, but results of studies remain conflicting. Methods: A systematic literature research of electronic databases (MEDLINE, Cochrane Library and Goggle Scholar covering the period from 1980 to January 2012) and meta-analysis of relevant cross-sectional and longitudinal studies were conducted to assess the association of CKD and cognitive decline. Results: Most cross-sectional and longitudinal studies suggest an association between cognitive impairment and CKD. Meta-analysis of cross-sectional and longitudinal studies comprising 54,779 participants yielded an association of cognitive decline in patients with CKD compared with patients without CKD (OR 1.65, 95% CI 1.32–2.05; p < 0.001, and OR 1.39, 95% CI 1.15–1.68; p < 0.001, respectively). Conclusion: This is the first meta-analysis assessing the impact of CKD on cognitive decline. Our results suggest CKD being a significant and independent somatic risk factor in the development of cognitive decline.

The preclinical stage of Alzheimer's disease is inconspicuous and there are - almost by definition - no reliable and valid symptoms and signs which would allow a very early diagnosis before the manifestation of irreversible deficits. For a clinical diagnosis of dementia, cognitive impairment has to be severe enough to compromise the activities of daily living. In the mild dementia stage, difficulties with declarative memory are usually prominent; depressive symptoms are not infrequent, but the patient usually manages to live alone. Supervision is needed in the moderate dementia stage, when other cognitive domains are affected in a more obvious manner and non-cognitive disturbances of thought, perception, affect, and behavior put increasing stress on the caregivers. Complete dependence of the patients, who frequently develop neurological disturbances, is typical of the late stage of illness. The life expectancy of patients with a clinical diagnosis of Alzheimer's disease is significantly reduced, but to date there is hope that the period of relative well-being and not of suffering can be prolonged with modern symptomatic treatment interventions.