26
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Impaired prefrontal synaptic gain in people with psychosis and their relatives during the mismatch negativity

      research-article

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The mismatch negativity (MMN) evoked potential, a preattentive brain response to a discriminable change in auditory stimulation, is significantly reduced in psychosis. Glutamatergic theories of psychosis propose that hypofunction of NMDA receptors (on pyramidal cells and inhibitory interneurons) causes a loss of synaptic gain control. We measured changes in neuronal effective connectivity underlying the MMN using dynamic causal modeling (DCM), where the gain (excitability) of superficial pyramidal cells is explicitly parameterised. EEG data were obtained during a MMN task—for 24 patients with psychosis, 25 of their first‐degree unaffected relatives, and 35 controls—and DCM was used to estimate the excitability (modeled as self‐inhibition) of (source‐specific) superficial pyramidal populations. The MMN sources, based on previous research, included primary and secondary auditory cortices, and the right inferior frontal gyrus. Both patients with psychosis and unaffected relatives (to a lesser degree) showed increased excitability in right inferior frontal gyrus across task conditions, compared to controls. Furthermore, in the same region, both patients and their relatives showed a reversal of the normal response to deviant stimuli; that is, a decrease in excitability in comparison to standard conditions. Our results suggest that psychosis and genetic risk for the illness are associated with both context‐dependent (condition‐specific) and context‐independent abnormalities of the excitability of superficial pyramidal cell populations in the MMN paradigm. These abnormalities could relate to NMDA receptor hypofunction on both pyramidal cells and inhibitory interneurons, and appear to be linked to the genetic aetiology of the illness, thereby constituting potential endophenotypes for psychosis. Hum Brain Mapp 37:351–365, 2016. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

          Related collections

          Most cited references131

          • Record: found
          • Abstract: found
          • Article: not found

          The positive and negative syndrome scale (PANSS) for schizophrenia.

          The variable results of positive-negative research with schizophrenics underscore the importance of well-characterized, standardized measurement techniques. We report on the development and initial standardization of the Positive and Negative Syndrome Scale (PANSS) for typological and dimensional assessment. Based on two established psychiatric rating systems, the 30-item PANSS was conceived as an operationalized, drug-sensitive instrument that provides balanced representation of positive and negative symptoms and gauges their relationship to one another and to global psychopathology. It thus constitutes four scales measuring positive and negative syndromes, their differential, and general severity of illness. Study of 101 schizophrenics found the four scales to be normally distributed and supported their reliability and stability. Positive and negative scores were inversely correlated once their common association with general psychopathology was extracted, suggesting that they represent mutually exclusive constructs. Review of five studies involving the PANSS provided evidence of its criterion-related validity with antecedent, genealogical, and concurrent measures, its predictive validity, its drug sensitivity, and its utility for both typological and dimensional assessment.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: found
            Is Open Access

            FieldTrip: Open Source Software for Advanced Analysis of MEG, EEG, and Invasive Electrophysiological Data

            This paper describes FieldTrip, an open source software package that we developed for the analysis of MEG, EEG, and other electrophysiological data. The software is implemented as a MATLAB toolbox and includes a complete set of consistent and user-friendly high-level functions that allow experimental neuroscientists to analyze experimental data. It includes algorithms for simple and advanced analysis, such as time-frequency analysis using multitapers, source reconstruction using dipoles, distributed sources and beamformers, connectivity analysis, and nonparametric statistical permutation tests at the channel and source level. The implementation as toolbox allows the user to perform elaborate and structured analyses of large data sets using the MATLAB command line and batch scripting. Furthermore, users and developers can easily extend the functionality and implement new algorithms. The modular design facilitates the reuse in other software packages.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Predictive coding in the visual cortex: a functional interpretation of some extra-classical receptive-field effects.

              We describe a model of visual processing in which feedback connections from a higher- to a lower-order visual cortical area carry predictions of lower-level neural activities, whereas the feedforward connections carry the residual errors between the predictions and the actual lower-level activities. When exposed to natural images, a hierarchical network of model neurons implementing such a model developed simple-cell-like receptive fields. A subset of neurons responsible for carrying the residual errors showed endstopping and other extra-classical receptive-field effects. These results suggest that rather than being exclusively feedforward phenomena, nonclassical surround effects in the visual cortex may also result from cortico-cortical feedback as a consequence of the visual system using an efficient hierarchical strategy for encoding natural images.
                Bookmark

                Author and article information

                Journal
                Hum Brain Mapp
                Hum Brain Mapp
                10.1002/(ISSN)1097-0193
                HBM
                Human Brain Mapping
                John Wiley and Sons Inc. (Hoboken )
                1065-9471
                1097-0193
                27 October 2015
                January 2016
                : 37
                : 1 ( doiID: 10.1002/hbm.v37.1 )
                : 351-365
                Affiliations
                [ 1 ] Division of PsychiatryUniversity College London LondonUnited Kingdom
                [ 2 ]Institute of Cognitive Neuroscience, University College London LondonUnited Kingdom
                [ 3 ] Department of PsychiatryHospital Beatriz Angelo LisbonPortugal
                [ 4 ] The South London and Maudsley NHS Foundation TrustNIHR Biomedical Research Centre for Mental Health at the Institute of Psychiatry, Psychology and Neuroscience, King's College London United Kingdom
                [ 5 ] Psychology Research LaboratoryHarvard Medical School, McLean Hospital Belmont MassachusettsUSA
                [ 6 ] Department of PsychiatryClinical Science Institute, National University of Ireland GalwayIreland
                [ 7 ] Department of PsychiatryClinical and Experimental Science Institute, University of Foggia Italy
                [ 8 ] The South London and Maudsley NHS Foundation TrustUniversity Hospital Lewisham LondonUnited Kingdom
                [ 9 ]Neuroepidemiology and Ageing Research Unit, Imperial College LondonUnited Kingdom
                [ 10 ]The Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London LondonUnited Kingdom
                Author notes
                [*] [* ]Correspondence to: Siri Ranlund, Division of Psychiatry, University College London, 6th Floor Maple House, 149 Tottenham Court Road, London W1T 7NF, United Kingdom. Email: s.ranlund@ 123456ucl.ac.uk
                Article
                HBM23035
                10.1002/hbm.23035
                4843949
                26503033
                5a0145d5-29ca-4349-acbf-e05fd944dd60
                © 2015 The Authors Human BrainMapping Published byWiley Periodicals, Inc.

                This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

                History
                : 01 July 2015
                : 30 September 2015
                : 13 October 2015
                Page count
                Pages: 15
                Funding
                Funded by: National Institute for Health Research, UK
                Award ID: PDA/02/06/016
                Categories
                Research Article
                Research Articles
                Custom metadata
                2.0
                hbm23035
                January 2016
                Converter:WILEY_ML3GV2_TO_NLMPMC version:4.8.6 mode:remove_FC converted:25.04.2016

                Neurology
                psychosis,schizophrenia,unaffected relatives,genetic risk,effective connectivity,dynamic causal modeling,dcm,cortical excitability,cortical gain,nmda receptor

                Comments

                Comment on this article