PubMed | BarcelonaBeta Brain Research Center, University Utrecht and University of Barcelona
Type: | Journal: Brain imaging and behavior | Year: 2016
The hippocampus is a key modulator of stress responses underlying depressive behavior. While FKBP5 has been found associated with a large number of stress-related outcomes and hippocampal features, its potential role in modifying the hippocampal communication transfer mechanisms with other brain regions remains largely unexplored. The putative genetic or environmental roots of the association between depression and structural connectivity alterations of the hippocampus were evaluated combining diffusion weighted imaging with both a quantitative genetics approach and molecular information on the rs1360780 single nucleotide polymorphism, in a sample of 54 informative monozygotic twins (27 pairs). Three main results were derived from the present analyses. First, graph-theoretical measures of hippocampal connectivity were altered in depression. Specifically, decreased connectivity strength and increased network centrality of the right hippocampus were found in depressed individuals. Second, these hippocampal alterations are potentially driven by familial factors (genes plus shared environment). Third, there is an additive interaction effect between FKBP5s rs1360780 variant and the graph-theoretical metrics of hippocampal connectivity to influence depression risk. Our data reveals alterations of the communication patterns between the hippocampus and the rest of the brain in depression, effects potentially driven by overall familial factors (genes plus shared twin environment) and modified by the FKBP5 gene.
PubMed | BarcelonaBeta Brain Research Center, University of Colorado at Boulder, University Pompeu Fabra, Hospital del Mar and 2 more.
Type: Journal Article | Journal: Human brain mapping | Year: 2016
Resting-state fMRI (RS-fMRI) has become a useful tool to investigate the connectivity structure of mental health disorders. In the case of major depressive disorder (MDD), recent studies regarding the RS-fMRI have found abnormal connectivity in several regions of the brain, particularly in the default mode network (DMN). Thus, the relevance of the DMN to self-referential thoughts and ruminations has made the use of the resting-state approach particularly important for MDD. The majority of such research has relied on the grand averaged functional connectivity measures based on the temporal correlations between the BOLD time series of various brain regions. We, in our study, investigated the variations in the functional connectivity over time at global and local level using RS-fMRI BOLD time series of 27 MDD patients and 27 healthy control subjects. We found that global synchronization and temporal stability were significantly increased in the MDD patients. Furthermore, the participants with MDD showed significantly increased overall average (static) functional connectivity (sFC) but decreased variability of functional connectivity (vFC) within specific networks. Static FC increased to predominance among the regions pertaining to the default mode network (DMN), while the decreased variability of FC was observed in the connections between the DMN and the frontoparietal network. Hum Brain Mapp 37:2918-2930, 2016. 2016 Wiley Periodicals, Inc.
PubMed | BarcelonaBeta Brain Research Center, University of Barcelona and University of Milan
Type: | Journal: Scientific reports | Year: 2016
Hosting nearly eighty percent of all human neurons, the cerebellum is functionally connected to large regions of the brain. Accumulating data suggest that some cerebellar resting-state alterations may constitute a key candidate mechanism for depressive psychopathology. While there is some evidence linking cerebellar function and depression, two topics remain largely unexplored. First, the genetic or environmental roots of this putative association have not been elicited. Secondly, while different mathematical representations of resting-state fMRI patterns can embed diverse information of relevance for health and disease, many of them have not been studied in detail regarding the cerebellum and depression. Here, high-resolution fMRI scans were examined to estimate functional connectivity patterns across twenty-six cerebellar regions in a sample of 48 identical twins (24 pairs) informative for depression liability. A network-based statistic approach was employed to analyze cerebellar functional networks built using three methods: the conventional approach of filtered BOLD fMRI time-series, and two analytic components of this oscillatory activity (amplitude envelope and instantaneous phase). The findings indicate that some environmental factors may lead to depression vulnerability through alterations of the neural oscillatory activity of the cerebellum during resting-state. These effects may be observed particularly when exploring the amplitude envelope of fMRI oscillations.
Dubois B.,Institute Du Cerveau Et Of La Moelle Epiniere |
Dubois B.,University Pierre and Marie Curie |
Feldman H.H.,University of British Columbia |
Jacova C.,S152 UBC Hospital |
And 39 more authors.
The Lancet Neurology | Year: 2014
In the past 8 years, both the International Working Group (IWG) and the US National Institute on Aging-Alzheimer's Association have contributed criteria for the diagnosis of Alzheimer's disease (AD) that better define clinical phenotypes and integrate biomarkers into the diagnostic process, covering the full staging of the disease. This Position Paper considers the strengths and limitations of the IWG research diagnostic criteria and proposes advances to improve the diagnostic framework. On the basis of these refinements, the diagnosis of AD can be simplified, requiring the presence of an appropriate clinical AD phenotype (typical or atypical) and a pathophysiological biomarker consistent with the presence of Alzheimer's pathology. We propose that downstream topographical biomarkers of the disease, such as volumetric MRI and fluorodeoxyglucose PET, might better serve in the measurement and monitoring of the course of disease. This paper also elaborates on the specific diagnostic criteria for atypical forms of AD, for mixed AD, and for the preclinical states of AD. © 2014 Elsevier Ltd.
PubMed | Barcelonabeta Brain Research Center, University of Malaga, Hospital Universitari i Politecnic La Fe Valencia and University of MalagaMalaga
Type: | Journal: Frontiers in human neuroscience | Year: 2016
Foreign accent syndrome (FAS) is a speech disorder that is defined by the emergence of a peculiar manner of articulation and intonation which is perceived as foreign. In most cases of acquired FAS (AFAS) the new accent is secondary to small focal lesions involving components of the bilaterally distributed neural network for speech production. In the past few years FAS has also been described in different psychiatric conditions (conversion disorder, bipolar disorder, and schizophrenia) as well as in developmental disorders (specific language impairment, apraxia of speech). In the present study, two adult males, one with atypical phonetic production and the other one with cluttering, reported having developmental FAS (DFAS) since their adolescence. Perceptual analysis by nave judges could not confirm the presence of foreign accent, possibly due to the mildness of the speech disorder. However, detailed linguistic analysis provided evidence of prosodic and segmental errors previously reported in AFAS cases. Cognitive testing showed reduced communication in activities of daily living and mild deficits related to psychiatric disorders. Psychiatric evaluation revealed long-lasting internalizing disorders (neuroticism, anxiety, obsessive-compulsive disorder, social phobia, depression, alexithymia, hopelessness, and apathy) in both subjects. Diffusion tensor imaging (DTI) data from each subject with DFAS were compared with data from a group of 21 age- and gender-matched healthy control subjects. Diffusion parameters (MD, AD, and RD) in predefined regions of interest showed changes of white matter microstructure in regions previously related with AFAS and psychiatric disorders. In conclusion, the present findings militate against the possibility that these two subjects have FAS of psychogenic origin. Rather, our findings provide evidence that mild DFAS occurring in the context of subtle, yet persistent, developmental speech disorders may be associated with structural brain anomalies. We suggest that the simultaneous involvement of speech and emotion regulation networks might result from disrupted neural organization during development, or compensatory or maladaptive plasticity. Future studies are required to examine whether the interplay between biological trait-like diathesis (shyness, neuroticism) and the stressful experience of living with mild DFAS lead to the development of internalizing psychiatric disorders.
PubMed | Barcelonabeta Brain Research Center, Hospital del Mar Medical Research Institute, Autonomous University of Barcelona and CIBER ISCIII
Type: Journal Article | Journal: Neurobiology of aging | Year: 2015
The progression of Alzheimers disease (AD) is characterized by complex trajectories of cerebral atrophy that are affected by interactions with age and apolipoprotein E allele 4 (APOE4) status. In this article, we report the nonlinear volumetric changes in gray matter across the full biological spectrum of the disease, represented by the AD-cerebrospinal fluid (CSF) index. This index reflects the subjects level of pathology and position along the AD continuum. We also evaluated the associated impact of the APOE4 genotype. The atrophy pattern associated with the AD-CSF index was highly symmetrical and corresponded with the typical AD signature. Medial temporal structures showed different atrophy dynamics along the progression of the disease. The bilateral parahippocampal cortices and a parietotemporal region extending from the middle temporal to the supramarginal gyrus presented an initial increase in volume which later reverted. Similarly, a portion of the precuneus presented a rather linear inverse association with the AD-CSF index whereas some other clusters did not show significant atrophy until index values corresponded to positive CSF tau values. APOE4 carriers showed steeper hippocampal volume reductions with AD progression. Overall, the reported atrophy patterns are in close agreement with those mentioned in previous findings. However, the detected nonlinearities suggest that there may be different pathological processes taking place at specific moments during AD progression and reveal the impact of the APOE4 allele.
Ritchie C.W.,University of Edinburgh |
Molinuevo J.L.,BarcelonaBeta Brain Research Center |
Truyen L.,Janssen Research and Development LLC |
Satlin A.,Eisai Inc |
And 2 more authors.
The Lancet Psychiatry | Year: 2016
Alzheimer's dementia affects more than 40 million people worldwide with substantial increases in prevalence anticipated. Interventions that either modify risk or reduce the development of early disease could delay the onset of dementia or reduce the rate of cognitive and functional decline. The European Prevention of Alzheimer's Dementia (EPAD) is a public-private consortium, funded by the Innovative Medicines Initiative, designed to increase the likelihood of successful development of new treatments for the secondary prevention of Alzheimer's dementia. EPAD will help with testing of different agents in this pre-dementia population through four components: improvement of access to existing cohorts and registries, development of the EPAD Registry of approximately 24 000 people who might be at increased risk of developing Alzheimer's dementia, establishment of the EPAD Longitudinal Cohort Study of 6000 people at any one time, and establishment of an adaptive, proof-of-concept trial including 1500 participants at any given time. The need for EPAD and its key design elements are described, and we discuss EPAD in relation to similar projects in progress. These parallel efforts reflect the need for a coordinated, worldwide battle against dementia, in which EPAD will play a crucial role. © 2016 Elsevier Ltd.
PubMed | BarcelonaBeta Brain Research Center, Janssen Research & Development LLC, University of Edinburgh, Eisai Inc and 2 more.
Type: Journal Article | Journal: The lancet. Psychiatry | Year: 2016
Alzheimers dementia affects more than 40 million people worldwide with substantial increases in prevalence anticipated. Interventions that either modify risk or reduce the development of early disease could delay the onset of dementia or reduce the rate of cognitive and functional decline. The European Prevention of Alzheimers Dementia (EPAD) is a public-private consortium, funded by the Innovative Medicines Initiative, designed to increase the likelihood of successful development of new treatments for the secondary prevention of Alzheimers dementia. EPAD will help with testing of different agents in this pre-dementia population through four components: improvement of access to existing cohorts and registries, development of the EPAD Registry of approximately 24,000 people who might be at increased risk of developing Alzheimers dementia, establishment of the EPAD Longitudinal Cohort Study of 6000 people at any one time, and establishment of an adaptive, proof-of-concept trial including 1500 participants at any given time. The need for EPAD and its key design elements are described, and we discuss EPAD in relation to similar projects in progress. These parallel efforts reflect the need for a coordinated, worldwide battle against dementia, in which EPAD will play a crucial role.
PubMed | Institute dInvestigacions Biomedica August Pi Sunyer IDIBAPS, BarcelonaBeta Brain Research Center, University of Barcelona and Mint Labs
Type: Journal Article | Journal: Journal of neuroimaging : official journal of the American Society of Neuroimaging | Year: 2016
Analysis of the structural connectomes can lead to powerful insights about the brains organization and damage. However, the accuracy and reproducibility of constructing the structural connectome done with different acquisition and reconstruction techniques is not well defined. In this work, we evaluated the reproducibility of the structural connectome techniques by performing test-retest (same day) and longitudinal studies (after 1 month) as well as analyzing graph-based measures on the data acquired from 22 healthy volunteers (6 subjects were used for the longitudinal study). We compared connectivity matrices and tract reconstructions obtained with the most typical acquisition schemes used in clinical application: diffusion tensor imaging (DTI), high angular resolution diffusion imaging (HARDI), and diffusion spectrum imaging (DSI). We observed that all techniques showed high reproducibility in the test-retest analysis (correlation >.9). However, HARDI was the only technique with low variability (2%) in the longitudinal assessment (1-month interval). The intraclass coefficient analysis showed the highest reproducibility for the DTI connectome, however, with more sparse connections than HARDI and DSI. Qualitative (neuroanatomical) assessment of selected tracts confirmed the quantitative results showing that HARDI managed to detect most of the analyzed fiber groups and fanning fibers. In conclusion, we found that HARDI acquisition showed the most balanced trade-off between high reproducibility of the connectome, higher rate of path detection and of fanning fibers, and intermediate acquisition times (10-15 minutes), although at the cost of higher appearance of aberrant fibers.
PubMed | BarcelonaBeta Brain Research Center, Karolinska Institutet, University of Barcelona, Hospital Universitari Son Espases and Institute dinvestigacions Biomediques August Pi i Sunyer IDIBAPS
Type: | Journal: NeuroImage. Clinical | Year: 2016
Several studies using Twenty-one patients with MTLE-HS underwent comprehensive preoperative evaluation; 18 (86%) of these underwent epilepsy surgery. We analyzed and compared the pattern of white matter (WM) alterations on DTI and cortical hypometabolism on We found widespread temporal and extratemporal Patients with MTLE-HS have widespread metabolic and microstructural abnormalities that involve similar regions. The distribution patterns of these gray and white matter abnormalities differ between patients with left or right MTLE, but also with the extent of the