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Author: Thomas Nichols (158)


Dec
1969

Identification of imaging biomarkers for schizophrenia is an important but still challenging problem. Even though considerable efforts have been made over the past decades, quantitative alterations between patients and healthy subjects have not yet provided a diagnostic measure with sufficient high sensitivity and specificity. One of the most important reasons is the lack of consistent findings, which is in part due to single-mode study, which only detects single dimensional information by each modality, and thus misses the most crucial differences between groups.

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Jan
2018

Smith and Nichols discuss "big data" human neuroimaging studies, with very large subject numbers and amounts of data. These studies provide great opportunities for making new discoveries about the brain but raise many new analytical challenges and interpretational risks.

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Jan
2018

Insight and inference for DVARS.

Neuroimage 2018 Jan 4;172:291-312. Epub 2018 Jan 4.
Soroosh Afyouni, Thomas E Nichols
Estimates of functional connectivity using resting state functional Magnetic Resonance Imaging (rs-fMRI) are acutely sensitive to artifacts and large scale nuisance variation. As a result much effort is dedicated to preprocessing rs-fMRI data and using diagnostic measures to identify bad scans. One such diagnostic measure is DVARS, the spatial root mean square of the data after temporal differencing.

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Feb
2018

The medial frontal cortex, including anterior midcingulate cortex, has been linked to multiple psychological domains, including cognitive control, pain, and emotion. However, it is unclear whether this region encodes representations of these domains that are generalizable across studies and subdomains. Additionally, if there are generalizable representations, do they reflect a single underlying process shared across domains or multiple domain-specific processes? We decomposed multivariate patterns of functional MRI activity from 270 participants across 18 studies into study-specific, subdomain-specific, and domain-specific components and identified latent multivariate representations that generalized across subdomains but were specific to each domain.

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Dec
1969

Big data initiatives such as the Enhancing NeuroImaging Genetics through Meta-Analysis consortium (ENIGMA), combine data collected by independent studies worldwide to achieve more generalizable estimates of effect sizes and more reliable and reproducible outcomes. Such efforts require harmonized image analyses protocols to extract phenotypes consistently. This harmonization is particularly challenging for resting state fMRI due to the wide variability of acquisition protocols and scanner platforms; this leads to site-to-site variance in quality, resolution and temporal signal-to-noise ratio (tSNR).

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Feb
2018

Cortical surface area is an increasingly used brain morphology metric that is ontogenetically and phylogenetically distinct from cortical thickness and offers a separate index of neurodevelopment and disease. However, the various existing methods for assessment of cortical surface area from magnetic resonance images have never been systematically compared. We show that the surface area method implemented in FreeSurfer corresponds closely to the exact, but computationally more demanding, mass-conservative (pycnophylactic) method, provided that images are smoothed.

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Jan
2018

Neuroimaging has evolved into a widely used method to investigate the functional neuroanatomy, brain-behaviour relationships, and pathophysiology of brain disorders, yielding a literature of more than 30,000 papers. With such an explosion of data, it is increasingly difficult to sift through the literature and distinguish spurious from replicable findings. Furthermore, due to the large number of studies, it is challenging to keep track of the wealth of findings.

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Jul
2017

Patterns of intrinsic human brain activity exhibit a profile of functional connectivity that is associated with behaviour and cognitive performance, and deteriorates with disease. This paper investigates the relative importance of genetic factors and the common environment between twins in determining this functional connectivity profile. Using functional magnetic resonance imaging (fMRI) on 820 subjects from the Human Connectome Project, and magnetoencephalographic (MEG) recordings from a subset, the heritability of connectivity among 39 cortical regions was estimated.

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Oct
2017

Permutation testing is a non-parametric method for obtaining the max null distribution used to compute corrected p-values that provide strong control of false positives. In neuroimaging, however, the computational burden of running such an algorithm can be significant. We find that by viewing the permutation testing procedure as the construction of a very large permutation testing matrix, T, one can exploit structural properties derived from the data and the test statistics to reduce the runtime under certain conditions.

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Jan
2017

The aim of this study was to evaluate whether ostomy industry patent activity (PA) is associated with patient outcomes and healthcare costs.
Two groups of ostomy pouch users based on manufacturer PA (low or high) were compared in terms of ostomy-related wear patterns, adverse events, and healthcare expenditure. Using Swedish registry data, all patients with newly formed stomas were divided between each group and were followed during a 2-year period (2011-12).

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Dec
1969

Atrial fibrillation (AF) is frequently detected after ischemic stroke for the first time, and brain regions involved in autonomic control have been suspected to trigger AF. We examined whether specific brain regions are associated with newly detected AF after ischemic stroke.
Patients with acute cerebral infarctions on diffusion-weighted magnetic resonance imaging were included in this lesion mapping study.

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Dec
2016

Most functional magnetic resonance imaging (fMRI) experiments record the brain's responses to samples of stimulus materials (e.g., faces or words).

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May
2017

Now over 20 years old, functional MRI (fMRI) has a large and growing literature that is best synthesised with meta-analytic tools. As most authors do not share image data, only the peak activation coordinates (foci) reported in the article are available for Coordinate-Based Meta-Analysis (CBMA). Neuroimaging meta-analysis is used to (i) identify areas of consistent activation; and (ii) build a predictive model of task type or cognitive process for new studies (reverse inference).

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Dec
1969

Attention-Deficit Hyperactive Disorder (ADHD) is one of the most common mental health disorders amongst school-aged children with an estimated prevalence of 5% in the global population (American Psychiatric Association, 2013). Stimulants, particularly methylphenidate (MPH), are the first-line option in the treatment of ADHD (Reeves and Schweitzer, 2004; Dopheide and Pliszka, 2009) and are prescribed to an increasing number of children and adolescents in the US and the UK every year (Safer et al., 1996; McCarthy et al.

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Jun
2017

Brain imaging is now ubiquitous in clinical practice and research. The case for bringing together large amounts of image data from well-characterised healthy subjects and those with a range of common brain diseases across the life course is now compelling. This report follows a meeting of international experts from multiple disciplines, all interested in brain image biobanking.

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Feb
2017

Given concerns about the reproducibility of scientific findings, neuroimaging must define best practices for data analysis, results reporting, and algorithm and data sharing to promote transparency, reliability and collaboration. We describe insights from developing a set of recommendations on behalf of the Organization for Human Brain Mapping and identify barriers that impede these practices, including how the discipline must change to fully exploit the potential of the world's neuroimaging data.

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Jul
2017

A recent Editorial in Cognitive Neuroscience reconsiders the findings of our work on the accuracy of false positive rate control with cluster inference in functional magnetic resonance imaging (fMRI), in particular criticizing our use of resting-state fMRI as a source for null data in the evaluation of task fMRI methods. We defend this use of resting fMRI data, as while there is much structure in this data, we argue it is representative of task data noise and task analysis software should be able to accommodate this noise. We also discuss a potential problem with Slotnick's own method.

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Jan
2017

Novel genetic loci associated with hippocampal volume.

Nat Commun 2017 Jan 18;8:13624. Epub 2017 Jan 18.
Derrek P Hibar, Hieab H H Adams, Neda Jahanshad, Ganesh Chauhan, Jason L Stein, Edith Hofer, Miguel E Renteria, Joshua C Bis, Alejandro Arias-Vasquez, M Kamran Ikram, Sylvane Desrivières, Meike W Vernooij, Lucija Abramovic, Saud Alhusaini, Najaf Amin, Micael Andersson, Konstantinos Arfanakis, Benjamin S Aribisala, Nicola J Armstrong, Lavinia Athanasiu, Tomas Axelsson, Ashley H Beecham, Alexa Beiser, Manon Bernard, Susan H Blanton, Marc M Bohlken, Marco P Boks, Janita Bralten, Adam M Brickman, Owen Carmichael, M Mallar Chakravarty, Qiang Chen, Christopher R K Ching, Vincent Chouraki, Gabriel Cuellar-Partida, Fabrice Crivello, Anouk Den Braber, Nhat Trung Doan, Stefan Ehrlich, Sudheer Giddaluru, Aaron L Goldman, Rebecca F Gottesman, Oliver Grimm, Michael E Griswold, Tulio Guadalupe, Boris A Gutman, Johanna Hass, Unn K Haukvik, David Hoehn, Avram J Holmes, Martine Hoogman, Deborah Janowitz, Tianye Jia, Kjetil N Jørgensen, Nazanin Karbalai, Dalia Kasperaviciute, Sungeun Kim, Marieke Klein, Bernd Kraemer, Phil H Lee, David C M Liewald, Lorna M Lopez, Michelle Luciano, Christine Macare, Andre F Marquand, Mar Matarin, Karen A Mather, Manuel Mattheisen, David R McKay, Yuri Milaneschi, Susana Muñoz Maniega, Kwangsik Nho, Allison C Nugent, Paul Nyquist, Loes M Olde Loohuis, Jaap Oosterlaan, Martina Papmeyer, Lukas Pirpamer, Benno Pütz, Adaikalavan Ramasamy, Jennifer S Richards, Shannon L Risacher, Roberto Roiz-Santiañez, Nanda Rommelse, Stefan Ropele, Emma J Rose, Natalie A Royle, Tatjana Rundek, Philipp G Sämann, Arvin Saremi, Claudia L Satizabal, Lianne Schmaal, Andrew J Schork, Li Shen, Jean Shin, Elena Shumskaya, Albert V Smith, Emma Sprooten, Lachlan T Strike, Alexander Teumer, Diana Tordesillas-Gutierrez, Roberto Toro, Daniah Trabzuni, Stella Trompet, Dhananjay Vaidya, Jeroen Van der Grond, Sven J Van der Lee, Dennis Van der Meer, Marjolein M J Van Donkelaar, Kristel R Van Eijk, Theo G M Van Erp, Daan Van Rooij, Esther Walton, Lars T Westlye, Christopher D Whelan, Beverly G Windham, Anderson M Winkler, Katharina Wittfeld, Girma Woldehawariat, Christiane Wolf, Thomas Wolfers, Lisa R Yanek, Jingyun Yang, Alex Zijdenbos, Marcel P Zwiers, Ingrid Agartz, Laura Almasy, David Ames, Philippe Amouyel, Ole A Andreassen, Sampath Arepalli, Amelia A Assareh, Sandra Barral, Mark E Bastin, Diane M Becker, James T Becker, David A Bennett, John Blangero, Hans van Bokhoven, Dorret I Boomsma, Henry Brodaty, Rachel M Brouwer, Han G Brunner, Randy L Buckner, Jan K Buitelaar, Kazima B Bulayeva, Wiepke Cahn, Vince D Calhoun, Dara M Cannon, Gianpiero L Cavalleri, Ching-Yu Cheng, Sven Cichon, Mark R Cookson, Aiden Corvin, Benedicto Crespo-Facorro, Joanne E Curran, Michael Czisch, Anders M Dale, Gareth E Davies, Anton J M De Craen, Eco J C De Geus, Philip L De Jager, Greig I De Zubicaray, Ian J Deary, Stéphanie Debette, Charles DeCarli, Norman Delanty, Chantal Depondt, Anita DeStefano, Allissa Dillman, Srdjan Djurovic, Gary Donohoe, Wayne C Drevets, Ravi Duggirala, Thomas D Dyer, Christian Enzinger, Susanne Erk, Thomas Espeseth, Iryna O Fedko, Guillén Fernández, Luigi Ferrucci, Simon E Fisher, Debra A Fleischman, Ian Ford, Myriam Fornage, Tatiana M Foroud, Peter T Fox, Clyde Francks, Masaki Fukunaga, J Raphael Gibbs, David C Glahn, Randy L Gollub, Harald H H Göring, Robert C Green, Oliver Gruber, Vilmundur Gudnason, Sebastian Guelfi, Asta K Håberg, Narelle K Hansell, John Hardy, Catharina A Hartman, Ryota Hashimoto, Katrin Hegenscheid, Andreas Heinz, Stephanie Le Hellard, Dena G Hernandez, Dirk J Heslenfeld, Beng-Choon Ho, Pieter J Hoekstra, Wolfgang Hoffmann, Albert Hofman, Florian Holsboer, Georg Homuth, Norbert Hosten, Jouke-Jan Hottenga, Matthew Huentelman, Hilleke E Hulshoff Pol, Masashi Ikeda, Clifford R Jack, Mark Jenkinson, Robert Johnson, Erik G Jönsson, J Wouter Jukema, René S Kahn, Ryota Kanai, Iwona Kloszewska, David S Knopman, Peter Kochunov, John B Kwok, Stephen M Lawrie, Hervé Lemaître, Xinmin Liu, Dan L Longo, Oscar L Lopez, Simon Lovestone, Oliver Martinez, Jean-Luc Martinot, Venkata S Mattay, Colm McDonald, Andrew M McIntosh, Francis J McMahon, Katie L McMahon, Patrizia Mecocci, Ingrid Melle, Andreas Meyer-Lindenberg, Sebastian Mohnke, Grant W Montgomery, Derek W Morris, Thomas H Mosley, Thomas W Mühleisen, Bertram Müller-Myhsok, Michael A Nalls, Matthias Nauck, Thomas E Nichols, Wiro J Niessen, Markus M Nöthen, Lars Nyberg, Kazutaka Ohi, Rene L Olvera, Roel A Ophoff, Massimo Pandolfo, Tomas Paus, Zdenka Pausova, Brenda W J H Penninx, G Bruce Pike, Steven G Potkin, Bruce M Psaty, Simone Reppermund, Marcella Rietschel, Joshua L Roffman, Nina Romanczuk-Seiferth, Jerome I Rotter, Mina Ryten, Ralph L Sacco, Perminder S Sachdev, Andrew J Saykin, Reinhold Schmidt, Helena Schmidt, Peter R Schofield, Sigurdur Sigursson, Andrew Simmons, Andrew Singleton, Sanjay M Sisodiya, Colin Smith, Jordan W Smoller, Hilkka Soininen, Vidar M Steen, David J Stott, Jessika E Sussmann, Anbupalam Thalamuthu, Arthur W Toga, Bryan J Traynor, Juan Troncoso, Magda Tsolaki, Christophe Tzourio, Andre G Uitterlinden, Maria C Valdés Hernández, Marcel Van der Brug, Aad van der Lugt, Nic J A van der Wee, Neeltje E M Van Haren, Dennis van 't Ent, Marie-Jose Van Tol, Badri N Vardarajan, Bruno Vellas, Dick J Veltman, Henry Völzke, Henrik Walter, Joanna M Wardlaw, Thomas H Wassink, Michael E Weale, Daniel R Weinberger, Michael W Weiner, Wei Wen, Eric Westman, Tonya White, Tien Y Wong, Clinton B Wright, Ronald H Zielke, Alan B Zonderman, Nicholas G Martin, Cornelia M Van Duijn, Margaret J Wright, W T Longstreth, Gunter Schumann, Hans J Grabe, Barbara Franke, Lenore J Launer, Sarah E Medland, Sudha Seshadri, Paul M Thompson, M Arfan Ikram
The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel.

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Dec
1969

Functional neuroimaging techniques have transformed our ability to probe the neurobiological basis of behaviour and are increasingly being applied by the wider neuroscience community. However, concerns have recently been raised that the conclusions that are drawn from some human neuroimaging studies are either spurious or not generalizable. Problems such as low statistical power, flexibility in data analysis, software errors and a lack of direct replication apply to many fields, but perhaps particularly to functional MRI.

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Dec
1969

Only a tiny fraction of the data and metadata produced by an fMRI study is finally conveyed to the community. This lack of transparency not only hinders the reproducibility of neuroimaging results but also impairs future meta-analyses. In this work we introduce NIDM-Results, a format specification providing a machine-readable description of neuroimaging statistical results along with key image data summarising the experiment.

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Dec
1969

Novel genetic loci underlying human intracranial volume identified through genome-wide association.

Nat Neurosci 2016 12 3;19(12):1569-1582. Epub 2016 Oct 3.
Hieab H H Adams, Derrek P Hibar, Vincent Chouraki, Jason L Stein, Paul A Nyquist, Miguel E Rentería, Stella Trompet, Alejandro Arias-Vasquez, Sudha Seshadri, Sylvane Desrivières, Ashley H Beecham, Neda Jahanshad, Katharina Wittfeld, Sven J Van der Lee, Lucija Abramovic, Saud Alhusaini, Najaf Amin, Micael Andersson, Konstantinos Arfanakis, Benjamin S Aribisala, Nicola J Armstrong, Lavinia Athanasiu, Tomas Axelsson, Alexa Beiser, Manon Bernard, Joshua C Bis, Laura M E Blanken, Susan H Blanton, Marc M Bohlken, Marco P Boks, Janita Bralten, Adam M Brickman, Owen Carmichael, M Mallar Chakravarty, Ganesh Chauhan, Qiang Chen, Christopher R K Ching, Gabriel Cuellar-Partida, Anouk Den Braber, Nhat Trung Doan, Stefan Ehrlich, Irina Filippi, Tian Ge, Sudheer Giddaluru, Aaron L Goldman, Rebecca F Gottesman, Corina U Greven, Oliver Grimm, Michael E Griswold, Tulio Guadalupe, Johanna Hass, Unn K Haukvik, Saima Hilal, Edith Hofer, David Hoehn, Avram J Holmes, Martine Hoogman, Deborah Janowitz, Tianye Jia, Dalia Kasperaviciute, Sungeun Kim, Marieke Klein, Bernd Kraemer, Phil H Lee, Jiemin Liao, David C M Liewald, Lorna M Lopez, Michelle Luciano, Christine Macare, Andre Marquand, Mar Matarin, Karen A Mather, Manuel Mattheisen, Bernard Mazoyer, David R McKay, Rebekah McWhirter, Yuri Milaneschi, Nazanin Mirza-Schreiber, Ryan L Muetzel, Susana Muñoz Maniega, Kwangsik Nho, Allison C Nugent, Loes M Olde Loohuis, Jaap Oosterlaan, Martina Papmeyer, Irene Pappa, Lukas Pirpamer, Sara Pudas, Benno Pütz, Kumar B Rajan, Adaikalavan Ramasamy, Jennifer S Richards, Shannon L Risacher, Roberto Roiz-Santiañez, Nanda Rommelse, Emma J Rose, Natalie A Royle, Tatjana Rundek, Philipp G Sämann, Claudia L Satizabal, Lianne Schmaal, Andrew J Schork, Li Shen, Jean Shin, Elena Shumskaya, Albert V Smith, Emma Sprooten, Lachlan T Strike, Alexander Teumer, Russell Thomson, Diana Tordesillas-Gutierrez, Roberto Toro, Daniah Trabzuni, Dhananjay Vaidya, Jeroen Van der Grond, Dennis Van der Meer, Marjolein M J Van Donkelaar, Kristel R Van Eijk, Theo G M Van Erp, Daan Van Rooij, Esther Walton, Lars T Westlye, Christopher D Whelan, Beverly G Windham, Anderson M Winkler, Girma Woldehawariat, Christiane Wolf, Thomas Wolfers, Bing Xu, Lisa R Yanek, Jingyun Yang, Alex Zijdenbos, Marcel P Zwiers, Ingrid Agartz, Neelum T Aggarwal, Laura Almasy, David Ames, Philippe Amouyel, Ole A Andreassen, Sampath Arepalli, Amelia A Assareh, Sandra Barral, Mark E Bastin, Diane M Becker, James T Becker, David A Bennett, John Blangero, Hans van Bokhoven, Dorret I Boomsma, Henry Brodaty, Rachel M Brouwer, Han G Brunner, Randy L Buckner, Jan K Buitelaar, Kazima B Bulayeva, Wiepke Cahn, Vince D Calhoun, Dara M Cannon, Gianpiero L Cavalleri, Christopher Chen, Ching-Yu Cheng, Sven Cichon, Mark R Cookson, Aiden Corvin, Benedicto Crespo-Facorro, Joanne E Curran, Michael Czisch, Anders M Dale, Gareth E Davies, Eco J C De Geus, Philip L De Jager, Greig I de Zubicaray, Norman Delanty, Chantal Depondt, Anita L DeStefano, Allissa Dillman, Srdjan Djurovic, Gary Donohoe, Wayne C Drevets, Ravi Duggirala, Thomas D Dyer, Susanne Erk, Thomas Espeseth, Denis A Evans, Iryna O Fedko, Guillén Fernández, Luigi Ferrucci, Simon E Fisher, Debra A Fleischman, Ian Ford, Tatiana M Foroud, Peter T Fox, Clyde Francks, Masaki Fukunaga, J Raphael Gibbs, David C Glahn, Randy L Gollub, Harald H H Göring, Hans J Grabe, Robert C Green, Oliver Gruber, Vilmundur Gudnason, Sebastian Guelfi, Narelle K Hansell, John Hardy, Catharina A Hartman, Ryota Hashimoto, Katrin Hegenscheid, Andreas Heinz, Stephanie Le Hellard, Dena G Hernandez, Dirk J Heslenfeld, Beng-Choon Ho, Pieter J Hoekstra, Wolfgang Hoffmann, Albert Hofman, Florian Holsboer, Georg Homuth, Norbert Hosten, Jouke-Jan Hottenga, Hilleke E Hulshoff Pol, Masashi Ikeda, M Kamran Ikram, Clifford R Jack, Mark Jenkinson, Robert Johnson, Erik G Jönsson, J Wouter Jukema, René S Kahn, Ryota Kanai, Iwona Kloszewska, David S Knopman, Peter Kochunov, John B Kwok, Stephen M Lawrie, Hervé Lemaître, Xinmin Liu, Dan L Longo, W T Longstreth, Oscar L Lopez, Simon Lovestone, Oliver Martinez, Jean-Luc Martinot, Venkata S Mattay, Colm McDonald, Andrew M McIntosh, Katie L McMahon, Francis J McMahon, Patrizia Mecocci, Ingrid Melle, Andreas Meyer-Lindenberg, Sebastian Mohnke, Grant W Montgomery, Derek W Morris, Thomas H Mosley, Thomas W Mühleisen, Bertram Müller-Myhsok, Michael A Nalls, Matthias Nauck, Thomas E Nichols, Wiro J Niessen, Markus M Nöthen, Lars Nyberg, Kazutaka Ohi, Rene L Olvera, Roel A Ophoff, Massimo Pandolfo, Tomas Paus, Zdenka Pausova, Brenda W J H Penninx, G Bruce Pike, Steven G Potkin, Bruce M Psaty, Simone Reppermund, Marcella Rietschel, Joshua L Roffman, Nina Romanczuk-Seiferth, Jerome I Rotter, Mina Ryten, Ralph L Sacco, Perminder S Sachdev, Andrew J Saykin, Reinhold Schmidt, Peter R Schofield, Sigurdur Sigurdsson, Andy Simmons, Andrew Singleton, Sanjay M Sisodiya, Colin Smith, Jordan W Smoller, Hilkka Soininen, Velandai Srikanth, Vidar M Steen, David J Stott, Jessika E Sussmann, Anbupalam Thalamuthu, Henning Tiemeier, Arthur W Toga, Bryan J Traynor, Juan Troncoso, Jessica A Turner, Christophe Tzourio, Andre G Uitterlinden, Maria C Valdés Hernández, Marcel Van der Brug, Aad Van der Lugt, Nic J A Van der Wee, Cornelia M Van Duijn, Neeltje E M Van Haren, Dennis Van T Ent, Marie-Jose Van Tol, Badri N Vardarajan, Dick J Veltman, Meike W Vernooij, Henry Völzke, Henrik Walter, Joanna M Wardlaw, Thomas H Wassink, Michael E Weale, Daniel R Weinberger, Michael W Weiner, Wei Wen, Eric Westman, Tonya White, Tien Y Wong, Clinton B Wright, H Ronald Zielke, Alan B Zonderman, Ian J Deary, Charles DeCarli, Helena Schmidt, Nicholas G Martin, Anton J M De Craen, Margaret J Wright, Lenore J Launer, Gunter Schumann, Myriam Fornage, Barbara Franke, Stéphanie Debette, Sarah E Medland, M Arfan Ikram, Paul M Thompson
Intracranial volume reflects the maximally attained brain size during development, and remains stable with loss of tissue in late life. It is highly heritable, but the underlying genes remain largely undetermined. In a genome-wide association study of 32,438 adults, we discovered five previously unknown loci for intracranial volume and confirmed two known signals.

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Mar
2017

Two powerful methods for statistical inference on MRI brain images have been proposed recently, a non-stationary voxelation-corrected cluster-size test (CST) based on random field theory and threshold-free cluster enhancement (TFCE) based on calculating the level of local support for a cluster, then using permutation testing for inference. Unlike other statistical approaches, these two methods do not rest on the assumptions of a uniform and high degree of spatial smoothness of the statistic image. Thus, they are strongly recommended for group-level fMRI analysis compared to other statistical methods.

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Jan
2017

We propose a generalized reduced rank latent factor regression model (GRRLF) for the analysis of tensor field responses and high dimensional covariates. The model is motivated by the need from imaging-genetic studies to identify genetic variants that are associated with brain imaging phenotypes, often in the form of high dimensional tensor fields. GRRLF identifies from the structure in the data the effective dimensionality of the data, and then jointly performs dimension reduction of the covariates, dynamic identification of latent factors, and nonparametric estimation of both covariate and latent response fields.

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Jul
2017

Here we report an exploratory within-subject variance decomposition analysis conducted on a task-based fMRI dataset with an unusually large number of repeated measures (i.e., 500 trials in each of three different subjects) distributed across 100 functional scans and 9 to 10 different sessions.

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Dec
1969

Altered brain connectivity is implicated in the development and clinical burden of schizophrenia. Relative to matched controls, schizophrenia patients show (1) a global and regional reduction in the integrity of the brain's white matter (WM), assessed using diffusion tensor imaging (DTI) fractional anisotropy (FA), and (2) accelerated age-related decline in FA values. In the largest mega-analysis to date, we tested if differences in the trajectories of WM tract development influenced patient-control differences in FA.

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Dec
1969

The most widely used task functional magnetic resonance imaging (fMRI) analyses use parametric statistical methods that depend on a variety of assumptions. In this work, we use real resting-state data and a total of 3 million random task group analyses to compute empirical familywise error rates for the fMRI software packages SPM, FSL, and AFNI, as well as a nonparametric permutation method. For a nominal familywise error rate of 5%, the parametric statistical methods are shown to be conservative for voxelwise inference and invalid for clusterwise inference.

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Jun
2016

The development of magnetic resonance imaging (MRI) techniques has defined modern neuroimaging. Since its inception, tens of thousands of studies using techniques such as functional MRI and diffusion weighted imaging have allowed for the non-invasive study of the brain. Despite the fact that MRI is routinely used to obtain data for neuroscience research, there has been no widely adopted standard for organizing and describing the data collected in an imaging experiment.

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Nov
2016

Permutation tests are increasingly being used as a reliable method for inference in neuroimaging analysis. However, they are computationally intensive. For small, non-imaging datasets, recomputing a model thousands of times is seldom a problem, but for large, complex models this can be prohibitively slow, even with the availability of inexpensive computing power.

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Dec
1969

In computed tomography (CT), the spot geometry is one of the main sources of error in CT images. Since X-rays do not arise from a point source, artefacts are produced. In particular there is a penumbra effect, leading to poorly defined edges within a reconstructed volume.

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Aug
2016

Given the increasing number of neuroimaging publications, the automated knowledge extraction on brain-behavior associations by quantitative meta-analyses has become a highly important and rapidly growing field of research. Among several methods to perform coordinate-based neuroimaging meta-analyses, Activation Likelihood Estimation (ALE) has been widely adopted. In this paper, we addressed two pressing questions related to ALE meta-analysis: i) Which thresholding method is most appropriate to perform statistical inference? ii) Which sample size, i.

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Dec
1969

A data-driven hypothesis-free genome-wide association (GWA) approach in imaging genetics studies allows screening the entire genome to discover novel genes that modulate brain structure, chemistry, and function. However, a whole brain voxel-wise analysis approach in such genome-wide based imaging genetic studies can be computationally intense and also likely has low statistical power since a stringent multiple comparisons correction is needed for searching over the entire genome and brain. In imaging genetics with functional magnetic resonance imaging (fMRI) phenotypes, since many experimental paradigms activate focal regions that can be pre-specified based on a priori knowledge, reducing the voxel-wise search to single-value summary measures within a priori ROIs could prove efficient and promising.

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Mar
2016

Schizophrenia is a devastating psychiatric illness with high heritability. Brain structure and function differ, on average, between people with schizophrenia and healthy individuals. As common genetic associations are emerging for both schizophrenia and brain imaging phenotypes, we can now use genome-wide data to investigate genetic overlap.

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Apr
2016

In this work, we show how permutation methods can be applied to combination analyses such as those that include multiple imaging modalities, multiple data acquisitions of the same modality, or simply multiple hypotheses on the same data. Using the well-known definition of union-intersection tests and closed testing procedures, we use synchronized permutations to correct for such multiplicity of tests, allowing flexibility to integrate imaging data with different spatial resolutions, surface and/or volume-based representations of the brain, including non-imaging data. For the problem of joint inference, we propose and evaluate a modification of the recently introduced non-parametric combination (NPC) methodology, such that instead of a two-phase algorithm and large data storage requirements, the inference can be performed in a single phase, with reasonable computational demands.

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Dec
1969

In recent years, an increasing number of studies have used Voxel Based Morphometry (VBM) to compare a single patient with a psychiatric or neurological condition of interest against a group of healthy controls. However, the validity of this approach critically relies on the assumption that the single patient is drawn from a hypothetical population with a normal distribution and variance equal to that of the control group. In a previous investigation, we demonstrated that family-wise false positive error rate (i.

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Dec
1969

During strenuous exercise there is a progressive increase in lactate uptake and metabolism into the brain as workload and plasma lactate levels increase. Although it is now widely accepted that the brain can metabolize lactate, few studies have directly measured brain lactate following vigorous exercise. Here, we used ultra-high field magnetic resonance spectroscopy of the brain to obtain static measures of brain lactate, as well as brain glutamate and glutamine after vigorous exercise.

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Dec
1969

The hippocampus has been shown to demonstrate a remarkable degree of plasticity in response to a variety of tasks and experiences. For example, the size of the human hippocampus has been shown to increase in response to aerobic exercise. However, it is currently unknown what underlies these changes.

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Dec
1969

The psychosis high-risk state is accompanied by alterations in functional brain activity during working memory processing. We used binary automatic pattern-classification to discriminate between the at-risk mental state (ARMS), first episode psychosis (FEP) and healthy controls (HCs) based on n-back WM-induced brain activity. Linear support vector machines and leave-one-out-cross-validation were applied to fMRI data of matched ARMS, FEP and HC (19 subjects/group).

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Jan
2016

Speed with which brain performs information processing influences overall cognition and is dependent on the white matter fibers. To understand genetic influences on processing speed and white matter FA, we assessed processing speed and diffusion imaging fractional anisotropy (FA) in related individuals from two populations. Discovery analyses were performed in 146 individuals from large Old Order Amish (OOA) families and findings were replicated in 485 twins and siblings of the Human Connectome Project (HCP).

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Nov
2015

We investigated the relationship between individual subjects' functional connectomes and 280 behavioral and demographic measures in a single holistic multivariate analysis relating imaging to non-imaging data from 461 subjects in the Human Connectome Project. We identified one strong mode of population co-variation: subjects were predominantly spread along a single 'positive-negative' axis linking lifestyle, demographic and psychometric measures to each other and to a specific pattern of brain connectivity.

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Apr
2015

We present a multi-cohort shape heritability study, extending the fast spherical demons registration to subcortical shapes via medial modeling. A multi-channel demons registration based on vector spherical harmonics is applied to medial and curvature features, while controlling for metric distortion. We registered and compared seven subcortical structures of 1480 twins and siblings from the Queensland Twin Imaging Study and Human Connectome Project:and.

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Dec
2015

Under weak and reasonable assumptions, mainly that data are exchangeable under the null hypothesis, permutation tests can provide exact control of false positives and allow the use of various non-standard statistics. There are, however, various common examples in which global exchangeability can be violated, including paired tests, tests that involve repeated measurements, tests in which subjects are relatives (members of pedigrees) - any dataset with known dependence among observations. In these cases, some permutations, if performed, would create data that would not possess the original dependence structure, and thus, should not be used to construct the reference (null) distribution.

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Sep
2015

Cluster-size tests (CSTs) based on random field theory (RFT) are commonly adopted to identify significant differences in brain images. However, the use of RFT in CSTs rests on the assumption of uniform smoothness (stationarity). When images are non-stationary, CSTs based on RFT will likely lead to increased false positives in smooth regions and reduced power in rough regions.

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Sep
2015

More and more large-scale imaging genetic studies are being widely conducted to collect a rich set of imaging, genetic, and clinical data to detect putative genes for complexly inherited neuropsychiatric and neurodegenerative disorders. Several major big-data challenges arise from testing genome-wide (NC>12 million known variants) associations with signals at millions of locations (NV~10(6)) in the brain from thousands of subjects (n~10(3)). The aim of this paper is to develop a Fast Voxelwise Genome Wide Association analysiS (FVGWAS) framework to efficiently carry out whole-genome analyses of whole-brain data.

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Dec
1969

Here we present NeuroVault-a web based repository that allows researchers to store, share, visualize, and decode statistical maps of the human brain. NeuroVault is easy to use and employs modern web technologies to provide informative visualization of data without the need to install additional software. In addition, it leverages the power of the Neurosynth database to provide cognitive decoding of deposited maps.

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Jan
2016

NeuroVault.org is dedicated to storing outputs of analyses in the form of statistical maps, parcellations and atlases, a unique strategy that contrasts with most neuroimaging repositories that store raw acquisition data or stereotaxic coordinates. Such maps are indispensable for performing meta-analyses, validating novel methodology, and deciding on precise outlines for regions of interest (ROIs).

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Apr
2015

Understanding emotion is critical for a science of healthy and disordered brain function, but the neurophysiological basis of emotional experience is still poorly understood. We analyzed human brain activity patterns from 148 studies of emotion categories (2159 total participants) using a novel hierarchical Bayesian model. The model allowed us to classify which of five categories--fear, anger, disgust, sadness, or happiness--is engaged by a study with 66% accuracy (43-86% across categories).

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