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Grey matter

Benjamin A Thomas, Vesna Cuplov, Alexandre Bousse, Adriana Mendes, Kris Thielemans, Brian F Hutton, Kjell Erlandsson
Positron emission tomography (PET) images are degraded by a phenomenon known as the partial volume effect (PVE). Approaches have been developed to reduce PVEs, typically through the utilisation of structural information provided by other imaging modalities such as MRI or CT. These methods, known as partial volume correction (PVC) techniques, reduce PVEs by compensating for the effects of the scanner resolution, thereby improving the quantitative accuracy. The PETPVC toolbox described in this paper comprises a suite of methods, both classic and more recent approaches, for the purposes of applying PVC to PET data...
November 21, 2016: Physics in Medicine and Biology
Elijah Mak, Silvy Gabel, Habib Mirette, Li Su, Guy B Williams, Adam Waldman, Katie Wells, Karen Ritchie, Craig Ritchie, John O'Brien
The last decade has witnessed a proliferation of neuroimaging studies characterising brain changes associated with Alzheimer's disease (AD), where both widespread atrophy and 'signature' brain regions have been implicated. In parallel, a prolonged latency period has been established in AD, with abnormal cerebral changes beginning many years before symptom onset. This raises the possibility of early therapeutic intervention, even before symptoms, when treatments could have the greatest effect on disease-course modification...
October 21, 2016: Ageing Research Reviews
Ana Coito, Christoph M Michel, Pieter van Mierlo, Serge Vulliemoz, Gijs Plomp
: The importance of functional brain connectivity to study physiological and pathological brain activity has been widely recognized. Here, we aimed to 1) review a methodological pipeline to investigate directed functional connectivity between brain regions using source signals derived from high-density EEG; 2) elaborate on some methodological challenges; 3) apply this pipeline to temporal lobe epilepsy (TLE) patients and healthy controls to investigate directed functional connectivity differences in the theta and beta frequency bands during EEG epochs without visible pathological activity...
October 20, 2016: IEEE Transactions on Bio-medical Engineering
Javier Gonzalez-Castillo, Gang Chen, Thomas E Nichols, Peter A Bandettini
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. Within-subject variance was segregated into four primary components: variance across-sessions, variance across-runs within a session, variance across-blocks within a run, and residual measurement/modeling error. Our results reveal inhomogeneous and distinct spatial distributions of these variance components across significantly active voxels in grey matter...
October 20, 2016: NeuroImage
Stephanie Wong, Muireann Irish, Eric D Leshikar, Audrey Duarte, Maxime Bertoux, Greg Savage, John R Hodges, Olivier Piguet, Michael Hornberger
Encoding information in reference to the self enhances subsequent memory for the source of this information. In healthy adults, self-referential processing has been proposed to be mediated by the cortical midline structures (CMS), with functional differentiation between anterior-ventral, anterior-dorsal and posterior regions. While both Alzheimer's disease (AD) and behavioural-variant frontotemporal dementia (bvFTD) patients show source memory impairment, it remains unclear whether they show a typical memory advantage for self-referenced materials...
October 3, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
Jennifer L Whitwell, Joseph R Duffy, Mary M Machulda, Heather M Clark, Edythe A Strand, Matthew L Senjem, Jeffrey L Gunter, Anthony J Spychalla, Ronald C Petersen, Clifford R Jack, Keith A Josephs
Agrammatic aphasia can be observed in neurodegenerative disorders and has been traditionally linked with damage to Broca's area, although there have been disagreements concerning whether damage to Broca's area is necessary or sufficient for the development of agrammatism. We aimed to investigate the neuroanatomical correlates of the emergence of agrammatic aphasia utilizing a unique cohort of patients with primary progressive apraxia of speech (PPAOS) that did not have agrammatism at baseline but developed agrammatic aphasia over time...
September 30, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
Yuichi Nishiyama, Hidekazu Kanayama, Hiroshi Mori, Keiji Tada, Yasushi Yamamoto, Takashi Katsube, Haruo Takeshita, Kazunori Kawakami, Hajime Kitagaki
OBJECTIVES: This study examined the usefulness of statistical parametric mapping (SPM) for investigating postmortem changes on brain computed tomography (CT). METHODS: This retrospective study included 128 patients (23 - 100 years old) without cerebral abnormalities who underwent unenhanced brain CT before and after death. The antemortem CT (AMCT) scans and postmortem CT (PMCT) scans were spatially normalized using our original brain CT template, and postmortem changes of CT values (in Hounsfield units; HU) were analysed by the SPM technique...
October 21, 2016: European Radiology
David Holmes
No abstract text is available yet for this article.
October 21, 2016: Nature Reviews. Endocrinology
Chuanjun Zhuo, Jiajia Zhu, Chunli Wang, Hongru Qu, Xiaolei Ma, Wen Qin
Alterations in grey matter structure and functional connectivity (FC) are pathological features of major depressive disorder (MDD). However, the relationship between brain structural and functional impairments in MDD remains uncertain. Thus, the aim of this study was to investigate the relationship between alterations in grey matter volume (GMV) and resting-state global functional connectivity density (rs-gFCD) in MDD. Forty-five patients with MDD and 48 healthy controls underwent structural and resting-state functional magnetic resonance imaging (fMRI)...
October 20, 2016: Brain Imaging and Behavior
Robert S C Amaral, Min Tae M Park, Gabriel A Devenyi, Vivian Lynn, Jon Pipitone, Julie Winterburn, Sofia Chavez, Mark Schira, Nancy Lobaugh, Aristotle N Voineskos, Jens C Pruessner, M Mallar Chakravarty
Recently, much attention has been focused on the definition and structure of the hippocampus and its subfields, while the projections from the hippocampus have been relatively understudied. Here, we derive a reliable protocol for manual segmentation of hippocampal white matter regions (alveus, fimbria, and fornix) using high-resolution magnetic resonance images that are complementary to our previous definitions of the hippocampal subfields, both of which are freely available at
October 17, 2016: NeuroImage
J E Isenor, N T Edwards, T A Alia, K L Slayter, D M MacDougall, S A McNeil, S K Bowles
BACKGROUND: Underutilization of vaccination programs remains a significant public health concern. Pharmacists serve as educators, facilitators, and in some jurisdictions, as administrators of vaccines. Though pharmacists have been involved with immunizations in various ways for many years, there has yet to be a systematic review assessing the impact of pharmacists as immunizers in these three roles. OBJECTIVE: To complete a systematic review of the literature on the impact of pharmacists as educators, facilitators, and administrators of vaccines on immunization rates...
November 11, 2016: Vaccine
Damien Seth Hunter, Susan J Hazel, Karen L Kind, Hong Liu, Danila Marini, Lynne C Giles, Miles J De Blasio, Julie A Owens, Julia B Pitcher, Kathryn L Gatford
Poor perinatal growth in humans results in asymmetrical grey matter loss in fetuses and infants and increased functional and behavioural asymmetry, but specific contributions of pre- and postnatal growth are unclear. We therefore compared strength and direction of lateralization in obstacle avoidance and maze exit preference tasks in offspring of placentally restricted (PR: 10M, 13F) and control (CON: 23M, 17F) sheep pregnancies at 18 and 40 weeks of age, and examined gross brain structure of the prefrontal cortex at 52 weeks of age (PR: 14M, 18F; CON: 23M, 25F)...
October 19, 2016: Laterality
Sungjin Im, Sang-Gu Lee, Jeonghwan Lee, Siekyeong Kim, Chul-Jin Shin, Jeong-Woo Son, Gawon Ju, Sang-Ick Lee
OBJECTIVE: The structural alteration of brain shown in patients with alcohol use disorder (AUD) can originate from both alcohol effects and genetic or developmental processes. We compared surface-based parameters of patients with AUD with healthy controls to prove the applicability of surface-based morphometry with head size correction and to determine the areas that were sensitive to brain alteration related to AUD. METHODS: Twenty-six abstinent male patients with AUD (alcohol group, mean abstinence=13...
September 2016: Psychiatry Investigation
Tengfei Guo, Matthias Brendel, Timo Grimmer, Axel Rominger, Igor Yakushev
: Knowledge about spatial and temporal patterns of beta-amyloid (Aβ) accumulation is essential for understanding Alzheimer's disease (AD) and for design of anti-amyloid drug trials. Here, we tested if the regional pattern of longitudinal Aβ accumulation can be predicted by baseline amyloid PET. METHODS: Analyzed were baseline and 2 years follow-up (18)F-florbetapir PET data from 58 patients with incipient and manifest dementia due to Alzheimer's disease (AD). By determining how fast amyloid deposits in a given region relative to the whole brain grey matter, a pseudo-temporal accumulation rate for each region was calculated...
October 6, 2016: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
Martina F Callaghan, Siawoosh Mohammadi, Nikolaus Weiskopf
Quantitative MRI (qMRI) provides standardized measures of specific physical parameters that are sensitive to the underlying tissue microstructure and are a first step towards achieving maps of biologically relevant metrics through in vivo histology using MRI. Recently proposed models have described the interdependence of qMRI parameters. Combining such models with the concept of image synthesis points towards a novel approach to synthetic qMRI, in which maps of fundamentally different physical properties are constructed through the use of biophysical models...
October 18, 2016: NMR in Biomedicine
Alexander U Brandt, Elena Meinert-Bohn, Jan Leo Rinnenthal, Hanna Zimmermann, Janine Mikolajczak, Timm Oberwahrenbrock, Sebastian Papazoglou, Caspar F Pfüller, Johann Schinzel, Björn Tackenberg, Friedemann Paul, Katrin Hahn, Judith Bellmann-Strobl
BACKGROUND: The PMP22 gene encodes a protein integral to peripheral myelin. Its deletion leads to hereditary neuropathy with liability to pressure palsies (HNPP). PMP22 is not expressed in the adult central nervous system, but previous studies suggest a role in CNS myelin development. The objective of this study was to identify potential structural and functional alterations in the afferent visual system in HNPP patients. METHODS: Twenty HNPP patients and 18 matched healthy controls (HC) were recruited in a cross-sectional study...
2016: PloS One
Matthew D Sacchet, M Catalina Camacho, Emily E Livermore, Ewart A C Thomas, Ian H Gotlib
BACKGROUND: Growing evidence indicates that major depressive disorder (MDD) is characterized by accelerated biological aging, including greater age-related changes in physiological functioning. The disorder is also associated with abnormal neural reward circuitry, particularly in the basal ganglia (BG). Here we assessed age-related changes in BG volume in both patients with MDD and healthy control participants. METHODS: We obtained whole-brain T1-weighted images from patients with MDD and healthy controls...
January 1, 2017: Journal of Psychiatry & Neuroscience: JPN
Marios C Yiannakas, Francesco Grussu, Polymnia Louka, Ferran Prados, Rebecca S Samson, Marco Battiston, Daniel R Altmann, Sebastien Ourselin, David H Miller, Claudia A M Gandini Wheeler-Kingshott
Diffusion tensor imaging (DTI) has recently started to be adopted into clinical investigations of spinal cord (SC) diseases. However, DTI applications to the lower SC are limited due to a number of technical challenges, related mainly to the even smaller size of the SC structure at this level, its position relative to the receiver coil elements and the effects of motion during data acquisition. Developing methods to overcome these problems would offer new means to gain further insights into microstructural changes of neurological conditions involving the lower SC, and in turn could help explain symptoms such as bladder and sexual dysfunction...
2016: PloS One
Benjamin Boller, Samira Mellah, Gabriel Ducharme-Laliberté, Sylvie Belleville
The aim of this study was to examine the relationships between educational attainment, regional grey matter volume, and functional working memory-related brain activation in older adults. The final sample included 32 healthy older adults with 8 to 22 years of education. Structural magnetic resonance imaging (MRI) was used to measure regional volume and functional MRI was used to measure activation associated with performing an n-back task. A positive correlation was found between years of education and cortical grey matter volume in the right medial and middle frontal gyri, in the middle and posterior cingulate gyri, and in the right inferior parietal lobule...
October 12, 2016: Brain Imaging and Behavior
Cali F Bartholomeusz, Vanessa L Cropley, Cassandra Wannan, Maria Di Biase, Patrick D McGorry, Christos Pantelis
OBJECTIVE: This review critically examines the structural neuroimaging evidence in psychotic illness, with a focus on longitudinal imaging across the first-episode psychosis and ultra-high-risk of psychosis illness stages. METHODS: A thorough search of the literature involving specifically longitudinal neuroimaging in early illness stages of psychosis was conducted. The evidence supporting abnormalities in brain morphology and altered neurodevelopmental trajectories is discussed in the context of a clinical staging model...
October 12, 2016: Australian and New Zealand Journal of Psychiatry
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