Abnormal functional activation and connectivity in the working memory network in early-onset schizophrenia.

Objective: Disruption within the working memory (WM) neural network is considered an integral feature of schizophrenia. The WM network, and the dorsolateral prefrontal cortex (DLPFC) in particular, undergo significant remodeling in late adolescence. Potential interactions between developmental changes in the WM network and disease-related processes for schizophrenia remain unclear.

Increased salience of gains versus decreased associative learning differentiate bipolar disorder from schizophrenia during incentive decision making.

Background: Abnormalities in incentive decision making, typically assessed using the Iowa Gambling Task (IGT), have been reported in both schizophrenia (SZ) and bipolar disorder (BD). We applied the Expectancy-Valence (E-V) model to determine whether motivational, cognitive and response selection component processes of IGT performance are differentially affected in SZ and BD.

Method: Performance on the IGT was assessed in 280 individuals comprising 70 remitted patients with SZ, 70 remitted patients with BD and 140 age-, sex- and IQ-matched healthy individuals.

Sex differences in bipolar disorder: a review of neuroimaging findings and new evidence.

Objectives: The sex of an individual is known to modulate the clinical presentation of bipolar disorder (BD), but little is known as to whether there are significant sex-by-diagnosis interactions on the brain structural and functional correlates of BD.

Methods: We conducted a literature review of magnetic resonance imaging (MRI) studies in BD, published between January 1990 and December 2010, reporting on the effects of sex and diagnosis. In the absence of any functional MRI (fMRI) studies, this review was supplemented by original data analyses focusing on sex-by-diagnosis interactions on patterns of brain activation obtained during tasks of working memory, incentive decision-making, and facial affect processing.

Multimodal analyses identify linked functional and white matter abnormalities within the working memory network in schizophrenia.

Background: Dysconnectivity between brain regions is thought to underlie the cognitive abnormalities that characterise schizophrenia (SZ). Consistent with this notion functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) studies in SZ have reliably provided evidence of abnormalities in functional integration and in white matter connectivity. Yet little is known about how alterations at the functional level related to abnormalities in anatomical connectivity.

Abnormal intrinsic and extrinsic connectivity within the magnetic mismatch negativity brain network in schizophrenia: a preliminary study.

Altered neuroplasticity is increasingly invoked as a mechanism underpinning dysconnectivity in schizophrenia. We used Dynamic Causal Modelling to compare connectivity during the magnetic auditory Mismatch Negativity (MMN), an index of error prediction, between schizophrenia patients and controls. Patients showed reduced intrinsic connectivity within the primary auditory cortex suggestive of impaired local neuronal adaptation and disrupted forward and backward extrinsic connectivity throughout the MMN network indicative of reduced higher order input in disambiguating activity in lower network nodes.

The neural correlates of coloured music: a functional MRI investigation of auditory-visual synaesthesia.

In auditory-visual synaesthesia, all kinds of sound can induce additional visual experiences. To identify the brain regions mainly involved in this form of synaesthesia, functional magnetic resonance imaging (fMRI) has been used during non-linguistic sound perception (chords and pure tones) in synaesthetes and non-synaesthetes. Synaesthetes showed increased activation in the left inferior parietal cortex (IPC), an area involved in multimodal integration, feature binding and attention guidance.

Effective connectivity during processing of facial affect: evidence for multiple parallel pathways.

The perception of facial affect engages a distributed cortical network. We used functional magnetic resonance imaging and dynamic causal modeling to characterize effective connectivity during explicit (conscious) categorization of affective stimuli in the human brain. Specifically, we examined the modulation of connectivity from posterior regions of the face-processing network to the lateral ventral prefrontal cortex (VPFC) during affective categorization and we tested for a potential role of the amygdala (AMG) in mediating this modulation.

Frontopolar cortical inefficiency may underpin reward and working memory dysfunction in bipolar disorder.

Objectives: Emotional dysregulation in bipolar disorder is thought to arise from dysfunction within prefrontal cortical regions involved in cognitive control coupled with increased or aberrant activation within regions engaged in emotional processing. The aim of this study was to determine the common and distinct patterns of functional brain abnormalities during reward and working memory processing in patients with bipolar disorder.

Methods: Participants were 36 euthymic bipolar disorder patients and 37 healthy comparison subjects matched for age, sex and IQ.

Dissociable functional connectivity changes during the Stroop task relating to risk, resilience and disease expression in bipolar disorder.

Reduced cognitive control is considered a core feature of bipolar disorder (BD). Abnormalities in ventrolateral prefrontal cortex (VLPFC) and other functionally linked regions that underpin cognitive control during the Stroop Colour Word Task (SCWT) have been reported in patients with BD and their relatives. In this functional magnetic resonance study we used psychophysiological interaction analysis to examine functional connectivity during the SCWT in 39 euthymic BD patients, 39 of their first-degree relatives (25 with no Axis I disorders and 14 with major depressive disorder) and 48 healthy controls.

Reduced P300 and P600 amplitude in the hollow-mask illusion in patients with schizophrenia.

Illusions provide a useful tool to study the mechanisms by which top-down and bottom-up processes interact in perception. Patients suffering from schizophrenia are not as subject to the hollow-mask illusion as healthy controls, since studies have shown that controls perceive a hollow mask as a normal face, while patients with schizophrenia do not. This insusceptibility to the illusion is indicating a weakened top-down processing in schizophrenia and little is understood about the neurobiology of this phenomenon.

The G allele of the JAK2 rs10974944 SNP, part of JAK2 46/1 haplotype, is strongly associated with JAK2 V617F-positive myeloproliferative neoplasms.

Polycythemia vera, essential thrombocythemia, and primary myelofibrosis are myeloproliferative neoplasms, characterized in a majority of cases by a unique somatic point mutation, JAK2 V617F. Recently, it was shown that JAK2 V617F occurs more frequently on a specific JAK2 haplotype, named JAK2 46/1. We genotyped 149 myeloproliferative neoplasms patients (69 had polycythemia vera, 65 had essential thrombocythemia, and 15 had primary myelofibrosis) with a known JAK2 V617F mutational status and 150 controls for the JAK2 rs10974944 (C/G) single nucleotide polymorphism, in which the G allele tags the 46/1 haplotype.

Impaired top-down processes in schizophrenia: a DCM study of ERPs.

Perception is not simply based on a hierarchical organization of the brain; it arises from an interplay between inputs from the environment and internal predictions of these inputs. It is an active process which involves an interaction between bottom-up information coming from the senses and feedback connections coming from higher-order cortical areas. In our experiment, we use the hollow-mask illusion to investigate the strength of top-down processes in schizophrenic patients and healthy controls.

Understanding why patients with schizophrenia do not perceive the hollow-mask illusion using dynamic causal modelling.

Patients suffering from schizophrenia are less susceptible to various visual illusions. For example, healthy participants perceive a hollow mask as a normal face, presumably due to the strength of constraining top-down influences, while patients with schizophrenia do not (Schneider, U., Leweke, F.

Arterial stenosis and atherothrombotic events in polycythemia vera and essential thrombocythemia.

Unlabelled: Patients with polycythemia vera (PV) and essential thrombocythemia (ET) are at risk of developing arterial and venous thromboembolic complications. Given the complex interaction between blood cells and the vessel wall, it is possible that atherogenesis may also be accelerated in these patients. We used Doppler arterial ultrasound to assess the presence of arterial stenosis in a cohort of PV and ET patients.