Reduced intrinsic visual cortical connectivity is associated with impaired perceptual closure in schizophrenia.

Sensory perceptual processing deficits, such as impaired visual object identification and perceptual closure, have been reported in schizophrenia. These perceptual impairments may be associated with neural deficits in visual association areas, including lateral occipital cortex and inferior temporal areas. However, it remains unknown if such deficits can be found in the intrinsic architecture of the visual system.

Abnormal Connectional Fingerprint in Schizophrenia: A Novel Network Analysis of Diffusion Tensor Imaging Data.

The graph theoretical analysis of structural magnetic resonance imaging (MRI) data has received a great deal of interest in recent years to characterize the organizational principles of brain networks and their alterations in psychiatric disorders, such as schizophrenia. However, the characterization of networks in clinical populations can be challenging, since the comparison of connectivity between groups is influenced by several factors, such as the overall number of connections and the structural abnormalities of the seed regions. To overcome these limitations, the current study employed the whole-brain analysis of connectional fingerprints in diffusion tensor imaging data obtained at 3 T of chronic schizophrenia patients (n = 16) and healthy, age-matched control participants (n = 17).

The When and Where of Working Memory Dysfunction in Early-Onset Schizophrenia-A Functional Magnetic Resonance Imaging Study.

Behavioral evidence indicates that working memory (WM) in schizophrenia is already impaired at the encoding stage. However, the neurophysiological basis of this primary deficit remains poorly understood. Using event-related fMRI, we assessed differences in brain activation and functional connectivity during the encoding, maintenance and retrieval stages of a visual WM task with 3 levels of memory load in 17 adolescents with early-onset schizophrenia (EOS) and 17 matched controls.

Adolescent brain maturation and cortical folding: evidence for reductions in gyrification.

Evidence from anatomical and functional imaging studies have highlighted major modifications of cortical circuits during adolescence. These include reductions of gray matter (GM), increases in the myelination of cortico-cortical connections and changes in the architecture of large-scale cortical networks. It is currently unclear, however, how the ongoing developmental processes impact upon the folding of the cerebral cortex and how changes in gyrification relate to maturation of GM/WM-volume, thickness and surface area.

Association between white matter fiber integrity and subclinical psychotic symptoms in schizophrenia patients and unaffected relatives.

In this study, we investigate whether aberrant integrity of white matter (WM) fiber tracts represents a genetically determined biological marker of schizophrenia (SZ), and its relation with clinical symptoms. We collected brain DTI data from 28 SZ patients, 18 first-degree relatives and 22 matched controls and used voxel-based analysis with tract-based spatial statistics (TBSS) in order to compare fractional anisotropy (FA) between groups. Mean voxel-based FA values from the entire skeleton of each group were compared.

Cortical-basal ganglia imbalance in schizophrenia patients and unaffected first-degree relatives.

Structural brain changes are amongst the most robust biological alterations in schizophrenia, and their investigation in unaffected relatives is important for an assessment of the contribution of genetic factors. In this cross-sectional morphometry study we investigated whether volume changes in SZ are linked with genetic vulnerability and whether these effects are separated from secondary illness effects. We compared density of grey and white matter using high-resolution 3D-anatomical MRI imaging data in 31 SZ patients, 29 first-degree relatives and 38 matched healthy controls, using Voxel-Based Morphometry (VBM) with SPM8.

Association between psychotic symptoms and cortical thickness reduction across the schizophrenia spectrum.

The current study provides a complete magnetic resonance imaging (MRI) analysis of thickness throughout the cerebral cortical mantle in patients with schizophrenia (SZ) and rigorously screened and matched unaffected relatives and controls and an assessment of its relation to psychopathology and subjective cognitive function. We analyzed 3D-anatomical MRI data sets, obtained at 3 T, from 3 different subject groups: 25 SZ patients, 29 first-degree relatives, and 37 healthy control subjects. We computed whole-brain cortical thickness using the Freesurfer software and assessed group differences.

Interhemispheric hypoconnectivity in schizophrenia: fiber integrity and volume differences of the corpus callosum in patients and unaffected relatives.

Changes in hemispheric asymmetry and inter-hemispheric connectivity have been reported in schizophrenia. However, the genetic contribution to these alterations is still unclear. In the current study, we applied an automatic segmentation method to structural MRI and diffusion tensor imaging (DTI) data and examined volume and fiber integrity of the corpus callosum (CC), the main interhemispheric fiber tract, in 16 chronic schizophrenia (SZ) patients, matched first degree relatives and controls.

Integrating temporal and spatial scales: human structural network motifs across age and region of interest size.

Human brain networks can be characterized at different temporal or spatial scales given by the age of the subject or the spatial resolution of the neuroimaging method. Integration of data across scales can only be successful if the combined networks show a similar architecture. One way to compare networks is to look at spatial features, based on fiber length, and topological features of individual nodes where outlier nodes form single node motifs whose frequency yields a fingerprint of the network.

Imaging derived cortical thickness reduction in high-functioning autism: key regions and temporal slope.

Cortical thickness (CT) changes possibly contribute to the complex symptomatology of autism. The aberrant developmental trajectories underlying such differences in certain brain regions and their continuation in adulthood are a matter of intense debate. We studied 28 adults with high-functioning autism (HFA) and 28 control subjects matched for age, gender, IQ and handedness.

Animated brain: a functional neuroimaging study on animacy experience.

Previous research used animated geometric figures to investigate social cognitive processes involved in ascribing mental states to others (e.g. mentalizing).

Reduced laterality as a trait marker of schizophrenia--evidence from structural and functional neuroimaging.

Laterality is a characteristic principle of the organization of the brain systems for language, and reduced hemispheric asymmetry has been considered a risk factor for schizophrenia. Here we sought support for the risk factor hypothesis by investigating whether reduced asymmetry of temporal lobe structure and function is also present in unaffected relatives. Sixteen schizophrenia patients, 16 age-matched first-degree relatives, and 15 healthy controls underwent high-resolution three-dimensional anatomical imaging and functional magnetic resonance imaging during auditory stimulation.

Resting-state functional network correlates of psychotic symptoms in schizophrenia.

Schizophrenia has been associated with aberrant intrinsic functional organization of the brain but the relationship of such deficits to psychopathology is unclear. In this study, we investigated associations between resting-state networks and individual psychopathology in sixteen patients with paranoid schizophrenia and sixteen matched healthy control participants. We estimated whole-brain functional connectivity of multiple networks using a combination of spatial independent component analysis and multiple regression analysis.

Neural synchrony and the development of cortical networks.

Recent data indicate that the synchronisation of oscillatory activity is relevant for the development of cortical circuits as demonstrated by the involvement of neural synchrony in synaptic plasticity and changes in the frequency and synchronisation of neural oscillations during development. Analyses of resting-state and task-related neural synchrony indicate that gamma-oscillations emerge during early childhood and precise temporal coordination through neural synchrony continues to mature until early adulthood. The late maturation of neural synchrony is compatible with changes in the myelination of cortico-cortical connections and with late development of GABAergic neurotransmission.

A fast B1-mapping method for the correction and normalization of magnetization transfer ratio maps at 3 T.

In neuroimaging, there is increasing interest in magnetization transfer (MT) techniques which yield information about bound water protons. One of the main applications is the investigation of the myelin integrity in the central nervous system (CNS). However, several problems may arise, in particular at high magnetic field strengths: B1 inhomogeneities may yield deviations of the MT saturation angle and thus non-uniformities of the measured MT ratio (MTR).

Anatomical brain connectivity and positive symptoms of schizophrenia: a diffusion tensor imaging study.

Structural brain changes in schizophrenia are well documented in the neuroimaging literature. The classical morphometric analyses of magnetic resonance imaging (MRI) data have recently been supplemented by diffusion tensor imaging (DTI), which mainly assesses changes in white matter (WM). DTI increasingly provides evidence for abnormal anatomical connectivity in schizophrenia, most often using fractional anisotropy (FA) as an indicator of the integrity of WM tracts.

Mental imagery vividness as a trait marker across the schizophrenia spectrum.

We investigated the vividness of mental imagery and its possible relationship with the predisposition towards hallucinations in 52 schizophrenia (SZ) patients, 44 of their first-degree relatives (R) and two healthy control groups (high-schizotypy [CHS; n=24]; low-schizotypy [CLS; n=24]). We investigated phenomenological and cognitive trait markers of schizophrenia, including cognitive correlates of hallucinations and vividness of mental imagery, and the influence of individual psychopathology. Overall, scores on the mental imagery questionnaire (QMI [Sheehan, P.

Summary of the 1st Schizophrenia International Research Society Conference oral sessions, Venice, Italy, June 21-25, 2008: the rapporteur reports.

The Schizophrenia International Research Society held its first scientific conference in Venice, Italy, June 21 to 25th, 2008. A wide range of controversial topics were presented in overlapping and plenary oral sessions. These included new genetic studies, controversies about early detection of schizophrenia and the prodrome, treatment issues, clinical characteristics, cognition, neuropathology and neurophysiology, other etiological considerations, substance abuse co-morbidity, and animal models for investigating disease etiology and for use as targets in drug studies.

Minds at rest? Social cognition as the default mode of cognizing and its putative relationship to the "default system" of the brain.

The "default system" of the brain has been described as a set of regions which are 'activated' during rest and 'deactivated' during cognitively effortful tasks. To investigate the reliability of task-related deactivations, we performed a meta-analysis across 12 fMRI studies. Our results replicate previous findings by implicating medial frontal and parietal brain regions as part of the "default system".

The corpus callosum in schizophrenia-volume and connectivity changes affect specific regions.

The corpus callosum (CC) is of great interest for pathophysiological models of schizophrenia. Volume and structural integrity of the CC have been examined by volumetric and diffusion tensor imaging (DTI) studies, but results were not consistent across methods or studies. A possible explanation may be varying methodologies and accuracy of measurements based on a single slice or small regions of interest.

Contribution of impaired early-stage visual processing to working memory dysfunction in adolescents with schizophrenia: a study with event-related potentials and functional magnetic resonance imaging.

Context: Working memory (WM) deficits in patients with schizophrenia have mainly been associated with prefrontal dysfunction. However, the contribution of perceptual deficits and abnormalities in sensory areas has not been explored. The present study closes this important gap in our understanding of WM dysfunction in schizophrenia by monitoring neural activity during WM encoding and retrieval with event-related potentials (ERPs) and functional magnetic resonance imaging (fMRI).

Visual hallucinations in schizophrenia investigated with functional magnetic resonance imaging.

We investigated a 27-year old patient with paranoid schizophrenia. Brain activity related to visual hallucinations was found in higher visual areas corresponding to the content of the hallucinations (faces, bodies, scenes) and the hippocampus. We assume that the hippocampal activity is related to the retrieval of visual images from memory and that sensory cortex activity is related to the vividness of the perceptual experience.

Automated segmentation of lateral ventricles from human and primate magnetic resonance images using cognition network technology.

Automatic segmentation of different types of tissue from magnetic resonance images is of great importance for clinical and research applications, particularly large-scale and longitudinal studies of brain pathology. We developed a fully automated algorithm for the segmentation of lateral ventricles from cranial magnetic resonance images. This problem is of interest in the study of schizophrenia, dementia and other neuropsychiatric disorders.