Author
Iris E. C. Sommer
Other affiliations: University of Toronto, University of Michigan, University of Groningen ...read more
Bio: Iris E. C. Sommer is an academic researcher from University Medical Center Groningen. The author has contributed to research in topics: Schizophrenia & Psychosis. The author has an hindex of 68, co-authored 394 publications receiving 16545 citations. Previous affiliations of Iris E. C. Sommer include University of Toronto & University of Michigan.
Papers published on a yearly basis
Papers
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TL;DR: In this article, four monoclonal antibodies are characterized from a fusion of mouse myeloma P3-NS1/1-Ag4-1 with spleen cells from BALB/c mice immunized with white matter from bovine corpus callosum.
1,112 citations
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TL;DR: It is shown here that a carbohydrate moiety recognized by L2 and HNK-1 monoclonal antibodies, is present in mouse N-CAM and LI, which points to a previously undetected molecular diversity which may have functional implications for modulating cell adhesion during development.
Abstract: Cell surface molecules have been implicated in cell interactions which underlie formation of the nervous system. The analysis of the functional properties of such molecules has profited from the combined use of antibodies and cell culture systems. It has been suggested that the interplay between these molecules modulates cell-to-cell interaction at critical developmental stages. In the mouse, N-CAM and L1 antigen have been shown to mediate Ca2+-independent adhesion among neural cells. N-CAM plays a role in fasciculation of neurites and formation of neuromuscular junction. L1 is apparently not involved in synaptogenesis, but in migration of granule cell neurones in the developing mouse cerebellar cortex. The two antigens are distinct molecular and functional entities which act synergistically in aggregation of neuroblastoma and early postnatal cerebellar cells. In view of a certain similarity in function between the two groups of molecules, it was not surprising to find that structural similarities are detectable by the monoclonal antibody L2. We show here that a carbohydrate moiety recognized by L2 and HNK-1 monoclonal antibodies, is present in mouse N-CAM and L1. The L2 epitope appears on all major neural cell types but not all N-CAM molecules express it. This heterogeneity points to a previously undetected molecular diversity which may have functional implications for modulating cell adhesion during development.
722 citations
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TL;DR: The authors present consensus guidelines that operationalize criteria for determining and reporting treatment resistance, adequate treatment, and treatment response, providing a benchmark for research and clinical translation in schizophrenia.
Abstract: Objective:Research and clinical translation in schizophrenia is limited by inconsistent definitions of treatment resistance and response. To address this issue, the authors evaluated current approaches and then developed consensus criteria and guidelines.Method:A systematic review of randomized antipsychotic clinical trials in treatment-resistant schizophrenia was performed, and definitions of treatment resistance were extracted. Subsequently, consensus operationalized criteria were developed through 1) a multiphase, mixed methods approach, 2) identification of key criteria via an online survey, and 3) meetings to achieve consensus.Results:Of 2,808 studies identified, 42 met inclusion criteria. Of these, 21 studies (50%) did not provide operationalized criteria. In the remaining studies, criteria varied considerably, particularly regarding symptom severity, prior treatment duration, and antipsychotic dosage thresholds; only two studies (5%) utilized the same criteria. The consensus group identified minimu...
618 citations
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TL;DR: It is time to provide rTMS as a clinical treatment method for depression, for auditory verbal hallucinations, and possibly for negative symptoms, as well as for electroconvulsive treatment for depression.
Abstract: Objective: Repetitive transcranial magnetic stimulation (rTMS) is a safe treatment method with few side effects However, efficacy for various psychiatric disorders is currently not clear Data sources: A literature search was performed from 1966 through October 2008 using PubMed, Ovid Medline, Embase Psychiatry, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, and PsycINFO The following search terms were used transcranial magnetic stimulation, TMS, repetitive TMS, psychiatry, mental disorder, psychiatric disorder, anxiety disorder, attention-deficit hyperactivity disorder, bipolar disorder, catatonia, mama, depression, obsessive-compulsive disorder, psychosis, posttraumatic stress disorder, schizophrenia, Tourette's syndrome, bulimia nervosa, and addiction. Study selection: Data were obtained from randomized, sham-controlled studies of rTMS treatment for depression (34 studies), auditory verbal hallucinations (AVH, 7 studies), negative symptoms in schizophrenia (7 studies), and obsessive-compulsive disorder (OCD, 3 studies) Studies of rTMS versus electroconvulsive treatment (ECT, 6 studies) for depression were meta-analyzed. Data extraction: Standardized mean effect sizes of rTMS versus sham were computed based on pretreatment-posttreatment comparisons Data synthesis: The mean weighted effect size of rTMS versus sham for depression was 0.55 (P <001). Monotherapy with rTMS was more effective than rTMS as adjunctive to antidepressant medication. ECT was superior to rTMS in the treatment of depression (mean weighted effect size -0 47, P = 004) In the treatment of AVH, rTMS was superior to sham treatment, with a mean weighted effect size of 0.54 (P <001) The mean weighted effect size for rTMS versus sham in the treatment of negative symptoms in schizophrenia was 0.39 (P = 11) and for OCD, 0 15 (P = .52) Side effects were mild, yet more prevalent with high-frequency rTMS at frontal locations Conclusions: It is time to provide rTMS as a clinical treatment method for depression, for auditory verbal hallucinations, and possibly for negative symptoms We do not recommend rTMS for the treatment of OCD J Clin Psychiatry 2010,71(7).873-884 (C) Copyright 2010 Physicians Postgraduate Press, Inc
516 citations
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Katrina L. Grasby1, Neda Jahanshad2, Jodie N. Painter1, Lucía Colodro-Conde3 +356 more•Institutions (115)
TL;DR: Results support the radial unit hypothesis that different developmental mechanisms promote surface area expansion and increases in thickness and find evidence that brain structure is a key phenotype along the causal pathway that leads from genetic variation to differences in general cognitive function.
Abstract: The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder.
436 citations
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TL;DR: For the next few weeks the course is going to be exploring a field that’s actually older than classical population genetics, although the approach it’ll be taking to it involves the use of population genetic machinery.
Abstract: So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to
9,847 citations
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TL;DR: The editors have done a masterful job of weaving together the biologic, the behavioral, and the clinical sciences into a single tapestry in which everyone from the molecular biologist to the practicing psychiatrist can find and appreciate his or her own research.
Abstract: I have developed "tennis elbow" from lugging this book around the past four weeks, but it is worth the pain, the effort, and the aspirin. It is also worth the (relatively speaking) bargain price. Including appendixes, this book contains 894 pages of text. The entire panorama of the neural sciences is surveyed and examined, and it is comprehensive in its scope, from genomes to social behaviors. The editors explicitly state that the book is designed as "an introductory text for students of biology, behavior, and medicine," but it is hard to imagine any audience, interested in any fragment of neuroscience at any level of sophistication, that would not enjoy this book. The editors have done a masterful job of weaving together the biologic, the behavioral, and the clinical sciences into a single tapestry in which everyone from the molecular biologist to the practicing psychiatrist can find and appreciate his or
7,563 citations
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TL;DR: The present updated guidelines review issues of risk and safety of conventional TMS protocols, address the undesired effects and risks of emerging TMS interventions, the applications of TMS in patients with implanted electrodes in the central nervous system, and safety aspects of T MS in neuroimaging environments.
4,447 citations
01 Feb 2015
TL;DR: In this article, the authors describe the integrative analysis of 111 reference human epigenomes generated as part of the NIH Roadmap Epigenomics Consortium, profiled for histone modification patterns, DNA accessibility, DNA methylation and RNA expression.
Abstract: The reference human genome sequence set the stage for studies of genetic variation and its association with human disease, but epigenomic studies lack a similar reference. To address this need, the NIH Roadmap Epigenomics Consortium generated the largest collection so far of human epigenomes for primary cells and tissues. Here we describe the integrative analysis of 111 reference human epigenomes generated as part of the programme, profiled for histone modification patterns, DNA accessibility, DNA methylation and RNA expression. We establish global maps of regulatory elements, define regulatory modules of coordinated activity, and their likely activators and repressors. We show that disease- and trait-associated genetic variants are enriched in tissue-specific epigenomic marks, revealing biologically relevant cell types for diverse human traits, and providing a resource for interpreting the molecular basis of human disease. Our results demonstrate the central role of epigenomic information for understanding gene regulation, cellular differentiation and human disease.
4,409 citations
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TL;DR: It is suggested that this framework provides a parsimonious account of insula function in neurotypical adults, and may provide novel insights into the neural basis of disorders of affective and social cognition.
Abstract: The insula is a brain structure implicated in disparate cognitive, affective, and regulatory functions, including interoceptive awareness, emotional responses, and empathic processes. While classically considered a limbic region, recent evidence from network analysis suggests a critical role for the insula, particularly the anterior division, in high-level cognitive control and attentional processes. The crucial insight and view we present here is of the anterior insula as an integral hub in mediating dynamic interactions between other large-scale brain networks involved in externally oriented attention and internally oriented or self-related cognition. The model we present postulates that the insula is sensitive to salient events, and that its core function is to mark such events for additional processing and initiate appropriate control signals. The anterior insula and the anterior cingulate cortex form a “salience network” that functions to segregate the most relevant among internal and extrapersonal stimuli in order to guide behavior. Within the framework of our network model, the disparate functions ascribed to the insula can be conceptualized by a few basic mechanisms: (1) bottom–up detection of salient events, (2) switching between other large-scale networks to facilitate access to attention and working memory resources when a salient event is detected, (3) interaction of the anterior and posterior insula to modulate autonomic reactivity to salient stimuli, and (4) strong functional coupling with the anterior cingulate cortex that facilitates rapid access to the motor system. In this manner, with the insula as its integral hub, the salience network assists target brain regions in the generation of appropriate behavioral responses to salient stimuli. We suggest that this framework provides a parsimonious account of insula function in neurotypical adults, and may provide novel insights into the neural basis of disorders of affective and social cognition.
4,322 citations