101
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Abstract
Several common genetic variants have recently been discovered that appear to influence white matter microstructure, as measured by diffusion tensor imaging (DTI). Each genetic variant explains only a small proportion of the variance in brain microstructure, so we set out to explore their combined effect on the white matter integrity of the corpus callosum. We measured six common candidate single-nucleotide polymorphisms (SNPs) in the COMT, NTRK1, BDNF, ErbB4, CLU, and HFE genes, and investigated their individual and aggregate effects on white matter structure in 395 healthy adult twins and siblings (age: 20-30 years). All subjects were scanned with 4-tesla 94-direction high angular resolution diffusion imaging. When combined using mixed-effects linear regression, a joint model based on five of the candidate SNPs (COMT, NTRK1, ErbB4, CLU, and HFE) explained ≈ 6% of the variance in the average fractional anisotropy (FA) of the corpus callosum. This predictive model had detectable effects on FA at 82% of the corpus callosum voxels, including the genu, body, and splenium. Predicting the brain's fiber microstructure from genotypes may ultimately help in early risk assessment, and eventually, in personalized treatment for neuropsychiatric disorders in which brain integrity and connectivity are affected.
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102
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Williamson PC, Allman JM. A framework for interpreting functional networks in schizophrenia. Front Hum Neurosci 2012; 6:184. [PMID: 22737116 PMCID: PMC3380255 DOI: 10.3389/fnhum.2012.00184] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 06/02/2012] [Indexed: 01/14/2023] Open
Abstract
Some promising genetic correlates of schizophrenia have emerged in recent years but none explain more than a small fraction of cases. The challenge of our time is to characterize the neuronal networks underlying schizophrenia and other neuropsychiatric illnesses. Early models of schizophrenia have been limited by the ability to readily evaluate large-scale networks in living patients. With the development of resting state and advanced structural magnetic resonance imaging, it has become possible to do this. While we are at an early stage, a number of models of intrinsic brain networks have been developed to account for schizophrenia and other neuropsychiatric disorders. This paper reviews the recent voxel-based morphometry (VBM), diffusion tensor imaging (DTI), and resting functional magnetic resonance imaging literature in light of the proposed networks underlying these disorders. It is suggested that there is support for recently proposed models that suggest a pivotal role for the salience network. However, the interactions of this network with the default mode network and executive control networks are not sufficient to explain schizophrenic symptoms or distinguish them from other neuropsychiatric disorders. Alternatively, it is proposed that schizophrenia arises from a uniquely human brain network associated with directed effort including the dorsal anterior and posterior cingulate cortex (PCC), auditory cortex, and hippocampus while mood disorders arise from a different brain network associated with emotional encoding including the ventral anterior cingulate cortex (ACC), orbital frontal cortex, and amygdala. Both interact with the dorsolateral prefrontal cortex and a representation network including the frontal and temporal poles and the fronto-insular cortex, allowing the representation of the thoughts, feelings, and actions of self and others across time.
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Affiliation(s)
- Peter C Williamson
- Tanna Schulich Chair in Neuroscience and Mental Health, University of Western Ontario, London ON, Canada
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103
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Nowinski WL, Chua BC, Yang GL, Qian GY. Three-dimensional interactive and stereotactic human brain atlas of white matter tracts. Neuroinformatics 2012; 10:33-55. [PMID: 21505883 DOI: 10.1007/s12021-011-9118-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a human brain atlas of white matter (WM) tracts containing 40 major tracts, which is three-dimensional (3D), segmented, labeled, interactive, stereotactic and correlated to structure and vasculature. We consider: (1) WM accuracy by correlating WM tracts to underlying neuroanatomy and quantifying them; (2) balance between realism and completeness by processing a sequence of track volumes generated for various parameters with the increasing track number to enable a tract "shape convergence". MPRAGE and DTI in 64 directions of the same subject were acquired on 3 Tesla. The method has three steps: DTI-MPRAGE registration, 3D tract generation from DTI, to WM reconstruction from MPRAGE to parcellation into 17 components. 82 track volumes were generated for a wide spectrum of parameter values: Fractional Anisotropy threshold in [0.0125, 0.55] and trajectory angle lower than 45°, 60°, 65°, 70°, 75°, 80°, 85°, 90°. For each tract, a sequence of track volumes was processed to create/edit contours delineating this tract to achieve its shape convergence. The parcellated tracts were grouped into commissures, associations, projections and posterior fossa tracts, and labeled following Terminologia Anatomica. To facilitate that, a dedicated tract editor is developed which processes multiple track volumes, handles tracts in three representations (tracks, contours, envelopes); provides editing/visualization simultaneously on axial, coronal, sagittal planes; enables tract labeling and coloring; and provides numerous tools (track counting, smoothing and length thresholding; representation conversion and saving; structural atlas support). A stereotactic tract atlas along with parcellated WM was developed to explore in real-time any individual tract or their groups along with surrounding neuroanatomy.
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Affiliation(s)
- Wieslaw L Nowinski
- Biomedical Imaging Lab, Agency for Science Technology and Research, 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Singapore.
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104
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Ding AY, Chan KC, Wu EX. Effect of cerebrovascular changes on brain DTI quantitation: a hypercapnia study. Magn Reson Imaging 2012; 30:993-1001. [PMID: 22495243 DOI: 10.1016/j.mri.2012.02.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 12/09/2011] [Accepted: 02/29/2012] [Indexed: 11/15/2022]
Abstract
Quantitative diffusion tensor imaging (DTI) offers a valuable tool to probe the microstructural changes in neural tissues in vivo, where absolute quantitation accuracy and reproducibility are essential. It has been long recognized that measurement of apparent diffusion coefficient (ADC) using DTI could be influenced by the presence of water molecules in cerebrovasculature. However, little is known about to what extent such blood signal affects DTI quantitation. In this study, we quantitatively examined the effect of cerebral hemodynamic change on DTI indices by using a standard multislice echo planar imaging (EPI) spin echo (SE) DTI acquisition protocol and a rat model of hypercapnia. In response to 5% CO(2) challenge, mean, radial and axial diffusivities measured with diffusion factor (b-value) of b=1.0 ms/μm(2) were found to increase in whole brain (1.52%±0.22%, 1.66%±0.16% and 1.35%±0.37%, respectively), gray matter (1.56%±0.23%, 1.63%±0.14% and 1.47%±0.45%, respectively) and white matter regions (1.45%±0.28%, 1.88%±0.33% and 1.10%±0.26%, respectively). Fractional anisotropy (FA) was found to decrease by 1.67%±0.38%, 1.91%±0.59% and 1.46%±0.30% in whole brain, gray matter and white matter regions, respectively. In addition, these diffusivity increases and FA decreases became more pronounced at a lower b-value (b=0.3 ms/μm(2)). The results indicated that in vivo DTI quantitation in brain can be contaminated by vascular factors on the order of few percentages. Consequently, alterations in cerebrovasculature and hemodynamics can affect the DTI quantitation and its efficacy in characterizing the neural tissue microstructures in normal and diseased states. Caution should be taken in designing and interpreting quantitative DTI studies as all DTI indices can be potentially confounded by physiologic conditions and by cerebrovascular and hemodynamic characteristics.
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Affiliation(s)
- Abby Y Ding
- Laboratory of Biomedical Imaging and Signal Processing, Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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105
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Cigarette smoking and white matter microstructure in schizophrenia. Psychiatry Res 2012; 201:152-8. [PMID: 22386966 PMCID: PMC3319200 DOI: 10.1016/j.pscychresns.2011.08.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 08/10/2011] [Accepted: 08/19/2011] [Indexed: 11/22/2022]
Abstract
The majority of patients with schizophrenia smoke cigarettes. Both nicotine use and schizophrenia have been associated with alterations in brain white matter microstructure as measured by diffusion tensor imaging (DTI). The purpose of this study was to examine fractional anisotropy (FA) in smoking and non-smoking patients with schizophrenia and in healthy volunteers. A total of 43 patients (28 smoking and 15 non-smoking) with schizophrenia and 40 healthy, non-smoking participants underwent DTI. Mean FA was calculated in four global regions of interest (ROIs) (whole brain, cerebellum, brainstem, and total cortical) as well as in four regional ROIs (frontal, temporal, parietal and occipital lobes). The non-smoking patient group had a significantly higher intellectual quotient (IQ) compared with the patients who smoked, and our results varied according to whether IQ was included as a covariate. Without IQ correction, significant between-group effects for FA were found in four ROIs: total brain, total cortical, frontal lobe and the occipital lobe. In all cases the FA was lower among the smoking patient group, and highest in the control group. Smoking patients differed significantly from non-smoking patients in the frontal lobe ROI. However, these differences were no longer significant after IQ correction. FA differences between non-smoking patients and controls were not significant. Among smoking and non-smoking patients with schizophrenia but not healthy controls, FA was correlated with IQ. In conclusion, group effects of smoking on FA in schizophrenia might be mediated by IQ. Further, low FA in specific brain areas may be a neural marker for complex pathophysiology and risk for diverse problems such as schizophrenia, low IQ, and nicotine addiction.
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106
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Abstract
Individuals with schizotypal personality disorder (SPD) share genetic, phenomenologic, and cognitive abnormalities with people diagnosed with schizophrenia. To date, 15 structural MRI studies of the brain have examined size, and 3 diffusion tensor imaging studies have examined white matter connectivity in SPD. Overall, both types of structural neuroimaging modalities have shown temporal lobe abnormalities similar to those observed in schizophrenia, while frontal lobe regions appear to show more sparing. This intriguing pattern suggests that frontal lobe sparing may suppress psychosis, which is consistent with the idea of a possible neuroprotective factor. In this paper, we review these 18 studies and discuss whether individuals with SPD who both resemble and differ from schizophrenia patients in their phenomenology, share some or all of the structural brain imaging characteristics of schizophrenia. We attempt to group the MRI abnormalities in SPD into three patterns: 1) a spectrum of severity-abnormalities are similar to those observed in schizophrenia but not so severe; 2) a spectrum of region-abnormalities affecting some, but not all, brain regions affected in schizophrenia; and 3) a spectrum of compensation-abnormalities reflecting greater-than-normal white matter volume, possibly serving as a buffer or compensatory mechanism protecting the individual with SPD from the frank psychosis observed in schizophrenia.
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107
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Ling J, Merideth F, Caprihan A, Pena A, Teshiba T, Mayer AR. Head injury or head motion? Assessment and quantification of motion artifacts in diffusion tensor imaging studies. Hum Brain Mapp 2012; 33:50-62. [PMID: 21391258 PMCID: PMC6869898 DOI: 10.1002/hbm.21192] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 09/23/2010] [Accepted: 09/27/2010] [Indexed: 11/11/2022] Open
Abstract
The relationship between head motion and diffusion values such as fractional anisotropy (FA) and mean diffusivity (MD) is currently not well understood. Simulation studies suggest that head motion may introduce either a positive or negative bias, but this has not been quantified in clinical studies. Moreover, alternative measures for removing bias as result of head motion, such as the removal of problematic gradients, has been suggested but not carefully evaluated. The current study examined the impact of head motion on FA and MD across three common pipelines (tract-based spatial statistics, voxelwise, and region of interest analyses) and determined the impact of removing diffusion weighted images. Our findings from a large cohort of healthy controls indicate that while head motion was associated with a positive bias for both FA and MD, the effect was greater for MD. The positive bias was observed across all three analysis pipelines and was present following established protocols for data processing, suggesting that current techniques (i.e., correction of both image and gradient table) for removing motion bias are likely insufficient. However, the removal of images with gross artifacts did not fundamentally change the relationship between motion and DTI scalar values. In addition, Monte Carlo simulations suggested that the random removal of images increases the bias and reduces the precision of both FA and MD. Finally, we provide an example of how head motion can be quantified across different neuropsychiatric populations, which should be implemented as part of any diffusion tensor imaging quality assurance protocol.
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Affiliation(s)
- Josef Ling
- The Mind Research Network, Albuquerque, New Mexico
| | | | | | - Amanda Pena
- The Mind Research Network, Albuquerque, New Mexico
| | | | - Andrew R. Mayer
- The Mind Research Network, Albuquerque, New Mexico
- Neurology Department, University of New Mexico School of Medicine, Albuquerque, New Mexico
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108
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Bode MK, Mattila ML, Kiviniemi V, Rahko J, Moilanen I, Ebeling H, Tervonen O, Nikkinen J. White matter in autism spectrum disorders - evidence of impaired fiber formation. Acta Radiol 2011; 52:1169-74. [PMID: 22101385 DOI: 10.1258/ar.2011.110197] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Diffusion tensor imaging (DTI) enables measurements and visualization of the microstructure of neural fiber tracts. The existing literature on autism spectrum disorders (ASDs) and DTI is heterogenous both regarding methodology and results. PURPOSE To compare brain white matter of high-functioning individuals with ASDs and controls. MATERIAL AND METHODS Tract-based spatial statistics (TBSS), a voxel-based approach to DTI, was used to compare 27 subjects with ASDs (mean age 14.7 years, range 11.4-17.6 years, 20 boys, 7 girls) and 26 control subjects (mean age 14.5 years, range 11.7-17.3 years, 17 boys, 9 girls). Mean fractional anisotropy (FA) image (skeleton) was created and each subject's aligned FA data were then projected onto this skeleton. Voxelwise cross-subject statistics on the skeletonized FA data, mean diffusivity (MD), and measures of diffusion direction were calculated. Importantly, the data were corrected across the whole image instead of using ROI-based methods. RESULTS The ASD group showed significantly greater FA (P < 0.05, corrected) in the area containing clusters of optic radiation and the right inferior fronto-occipital fasciculus (iFOF). In the same area, λ(3) (representing transverse diffusion) was significantly reduced in the ASD group. No age-related changes were found. CONCLUSION The results suggest that the reduced transverse diffusion within the iFOF is related to abnormal information flow between the insular salience processing areas and occipital visual areas.
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Affiliation(s)
| | | | | | - Jukka Rahko
- Clinic of Child Psychiatry, Oulu University Hospital, Oulu, Finland
| | - Irma Moilanen
- Clinic of Child Psychiatry, Oulu University Hospital, Oulu, Finland
| | - Hanna Ebeling
- Clinic of Child Psychiatry, Oulu University Hospital, Oulu, Finland
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109
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Phillips OR, Clark KA, Woods RP, Subotnik KL, Asarnow RF, Nuechterlein KH, Toga AW, Narr KL. Topographical relationships between arcuate fasciculus connectivity and cortical thickness. Hum Brain Mapp 2011; 32:1788-801. [PMID: 20886580 PMCID: PMC3071430 DOI: 10.1002/hbm.21147] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 06/20/2010] [Accepted: 07/15/2010] [Indexed: 12/21/2022] Open
Abstract
The arcuate fasciculus (AF) connects cortical regions important in language processing, but how fiber coherence and organization relates to gray matter macrostructure remains uncharacterized. We used high-resolution structural and 30-direction diffusion imaging data from 36 healthy adults (24 male/12 female; mean age, 30.5 ± 9.8 years) to establish the relationships between AF microstructure and regional variations in cortical gray matter within language networks. Cortical pattern-matching algorithms were used to measure gray matter thickness at high-spatial density, and a validated diffusion tractography method was used to reconstruct the AF in the left and right hemisphere of each subject. Relationships between imaging measures and neuropsychological scores of verbal fluency were additionally assessed. Results revealed positive and highly topographical associations between arcuate fractional anisotropy (FA) and cortical thickness within anterior and posterior language regions and surrounding cortices, more prominently in the left hemisphere. These regional cortical thickness/FA relationships were primarily attributable to variations in radial diffusivity. Associations between cortical thickness and verbal fluency were observed in perisylvian language-related regions. Language scores were associated with left-hemisphere AF axial diffusivity, but not with AF FA or radial diffusivity. These findings thus suggest that particular components of white matter microstructure and regional increases in cortical thickness benefit aspects of language processing. Furthermore, the topographical relationships between independent measures of white matter and gray matter integrity suggest that rich developmental or environmental interactions influence brain structure and function where the presence and strength of such associations may elucidate pathophysiological processes influencing language systems.
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Affiliation(s)
- Owen R. Phillips
- Laboratory of Neuro Imaging, Geffen School of Medicine, University of California, Los Angeles, California
| | - Kristi A. Clark
- Laboratory of Neuro Imaging, Geffen School of Medicine, University of California, Los Angeles, California
| | - Roger P. Woods
- Department of Neurology, Ahmanson‐Lovelace Brain Mapping Center, Geffen School of Medicine, University of California, Los Angeles, California
- Department of Psychiatry and Biobehavioral Sciences, Geffen School of Medicine, University of California, Los Angeles, California
| | - Kenneth L. Subotnik
- Department of Psychiatry and Biobehavioral Sciences, Geffen School of Medicine, University of California, Los Angeles, California
| | - Robert F. Asarnow
- Department of Psychiatry and Biobehavioral Sciences, Geffen School of Medicine, University of California, Los Angeles, California
- Department of Psychology, University of California, Los Angeles, California
| | - Keith H. Nuechterlein
- Department of Psychiatry and Biobehavioral Sciences, Geffen School of Medicine, University of California, Los Angeles, California
- Department of Psychology, University of California, Los Angeles, California
| | - Arthur W. Toga
- Laboratory of Neuro Imaging, Geffen School of Medicine, University of California, Los Angeles, California
- Department of Neurology, Ahmanson‐Lovelace Brain Mapping Center, Geffen School of Medicine, University of California, Los Angeles, California
| | - Katherine L. Narr
- Laboratory of Neuro Imaging, Geffen School of Medicine, University of California, Los Angeles, California
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110
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Phillips OR, Nuechterlein KH, Asarnow RF, Clark KA, Cabeen R, Yang Y, Woods RP, Toga AW, Narr KL. Mapping corticocortical structural integrity in schizophrenia and effects of genetic liability. Biol Psychiatry 2011; 70:680-9. [PMID: 21571255 PMCID: PMC3838300 DOI: 10.1016/j.biopsych.2011.03.039] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 03/03/2011] [Accepted: 03/23/2011] [Indexed: 12/31/2022]
Abstract
BACKGROUND Structural and diffusion tensor imaging studies implicate gray and white matter (WM) abnormalities and disruptions of neural circuitry in schizophrenia. However, the structural integrity of the superficial WM, comprising short-range association (U-fibers) and intracortical axons, has not been investigated in schizophrenia. METHODS High-resolution structural and diffusion tensor images and sophisticated cortical pattern matching methods were used to measure and compare global and local variations in superficial WM fractional anisotropy between schizophrenia patients and their relatives and community comparison subjects and their relatives (n = 150). RESULTS Compared with control subjects, patients showed reduced superficial WM fractional anisotropy distributed across each hemisphere, particularly in left temporal and bilateral occipital regions (all p < .05, corrected). Furthermore, by modeling biological risk for schizophrenia in patients, patient relatives, and control subjects, fractional anisotropy was shown to vary in accordance with relatedness to a patient in both hemispheres and in the temporal and occipital lobes (p < .05, corrected). However, effects did not survive correction procedures for two-group comparisons between patient relatives and control subjects. CONCLUSIONS Results extend previous findings restricted to deep WM pathways to demonstrate that disturbances in corticocortical connectivity are associated with schizophrenia and might indicate a genetic predisposition for the disorder. Because the structural integrity of WM plays a crucial role in the functionality of networks linking gray matter regions, disturbances in the coherence and organization of fibers at the juncture of the neuropil might relate to features of schizophrenia at least partially attributable to disease-related genetic factors.
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111
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Stys PK. The axo-myelinic synapse. Trends Neurosci 2011; 34:393-400. [PMID: 21741098 DOI: 10.1016/j.tins.2011.06.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 06/01/2011] [Accepted: 06/04/2011] [Indexed: 01/19/2023]
Abstract
Axons have evolved to acquire myelination, enabling denser packing and speedier transmission. Although myelin is considered a passive insulator, recent reports suggest a more dynamic role. Axons, in turn, are endowed with neurotransmitter release and uptake systems along their trunks. Based on these observations, I argue that there may exist a new type of chemical synapse between axon and myelin, one that supports activity-dependent communication between the two. This raises intriguing possibilities of dynamic fine-tuning of the myelin sheath even in adulthood, efficient recruitment of resources for myelin maintenance and bi-directional signaling, whereby the axon informs its myelinating cell of its metabolic needs proportionally to the electrical traffic it is transmitting. This would also have implications for de- and dysmyelinating diseases should this axo-myelinic synapse become dysfunctional.
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Affiliation(s)
- Peter K Stys
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
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112
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Clark KA, Nuechterlein KH, Asarnow RF, Hamilton LS, Phillips OR, Hageman NS, Woods RP, Alger JR, Toga AW, Narr KL. Mean diffusivity and fractional anisotropy as indicators of disease and genetic liability to schizophrenia. J Psychiatr Res 2011; 45:980-8. [PMID: 21306734 PMCID: PMC3109158 DOI: 10.1016/j.jpsychires.2011.01.006] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 12/28/2010] [Accepted: 01/06/2011] [Indexed: 11/16/2022]
Abstract
The goals of this study were to first determine whether the fractional anisotropy (FA) and mean diffusivity (MD) of major white matter pathways associate with schizophrenia, and secondly to characterize the extent to which differences in these metrics might reflect a genetic predisposition to schizophrenia. Differences in FA and MD were identified using a comprehensive atlas-based tract mapping approach using diffusion tensor imaging and high-resolution structural data from 35 patients, 28 unaffected first-degree relatives of patients, 29 community controls, and 14 first-degree relatives of controls. Schizophrenia patients had significantly higher MD in the following tracts compared to controls: the right anterior thalamic radiations, the forceps minor, the bilateral inferior fronto-occipital fasciculus (IFO), the temporal component of the left superior longitudinal fasciculus (tSLF), and the bilateral uncinate. FA showed schizophrenia effects and a linear relationship to genetic liability (represented by schizophrenia patients, first-degree relatives, and controls) for the bilateral IFO, the left inferior longitudinal fasciculus (ILF), and the left tSLF. Diffusion tensor imaging studies have previously identified white matter abnormalities in all three of these tracts in schizophrenia; however, this study is the first to identify a significant genetic liability. Thus, FA of these three tracts may serve as biomarkers for studies seeking to identify how genes influence brain structure predisposing to schizophrenia. However, differences in FA and MD in frontal and temporal white matter pathways may be additionally driven by state variables that involve processes associated with the disease.
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Affiliation(s)
- Kristi A Clark
- Laboratory of Neuro Imaging, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA.
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113
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Pan H, Epstein J, Silbersweig DA, Stern E. New and emerging imaging techniques for mapping brain circuitry. ACTA ACUST UNITED AC 2011; 67:226-51. [DOI: 10.1016/j.brainresrev.2011.02.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 02/17/2011] [Accepted: 02/17/2011] [Indexed: 12/20/2022]
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114
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Kazlouski D, Rollin MD, Tregellas J, Shott ME, Jappe LM, Hagman JO, Pryor T, Yang TT, Frank GK. Altered fimbria-fornix white matter integrity in anorexia nervosa predicts harm avoidance. Psychiatry Res 2011; 192:109-16. [PMID: 21498054 PMCID: PMC3085716 DOI: 10.1016/j.pscychresns.2010.12.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/30/2010] [Accepted: 12/09/2010] [Indexed: 01/12/2023]
Abstract
The eating disorder anorexia nervosa (AN) is associated with high anxiety. The brain mechanisms that drive those behaviors are unknown. In this study we wanted to test whether brain white matter (WM) integrity is altered in AN, and related to heightened anxiety. Sixteen adult women with AN (mean age 24 ± 7 years) and 17 healthy control women (CW, mean age 25 ± 4 years) underwent diffusion tensor imaging (DTI) of the brain. The DTI brain images were used to calculate the fractional anisotropy (FA) of WM tracts, which is a measure for WM integrity. AN individuals compared to CW showed clusters of significantly reduced FA (p<0.05, corrected) in the bilateral fimbria-fornix and the fronto-occipital fasciculus, as well as the posterior cingulum WM. In the AN group, Harm Avoidance was predicted by FA in the left and right fimbria-fornix. Those findings were not due to WM volume deficits in AN. This study indicates that WM integrity is abnormal in AN in limbic and association pathways, which could contribute to disturbed feeding, emotion processing and body perception in AN. The prediction of Harm Avoidance in AN by fimbria-fornix WM integrity suggests that this pathway may be mechanistically involved in high anxiety in AN.
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Affiliation(s)
- Demitry Kazlouski
- Department of Psychiatry, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Michael D.H. Rollin
- Department of Psychiatry, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Jason Tregellas
- Department of Psychiatry, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
- Neuroscience Program, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
- Research Service, Denver VA Medical Center, Denver, CO, USA
| | - Megan E. Shott
- Department of Psychiatry, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Leah M. Jappe
- Department of Psychology, University of Minnesota, Minneapolis, MN, USA
| | - Jennifer O. Hagman
- Department of Psychiatry, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Tamara Pryor
- Eating Disorders Center Denver, Glendale, CO, USA
| | - Tony T. Yang
- Department of Psychiatry, University of California San Diego, San Diego, CA, USA
| | - Guido K.W. Frank
- Department of Psychiatry, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
- Neuroscience Program, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
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115
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Waters-Metenier SL, Toulopoulou T. Putative diffusion tensor neuroimaging endophenotypes in schizophrenia: a review of the early evidence. FUTURE NEUROLOGY 2011. [DOI: 10.2217/fnl.11.16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although schizophrenia has a high heritability, the genetic effects conferring diathesis to schizophrenia are thought to be complex and underlain by multifactorial polygenic inheritance. ‘Endophenotypes’, or ‘intermediate phenotypes’, are narrowed constructs of genetic risk that are assumed to be more proximal to the gene effects in the disease pathway than clinical phenotypes. A current aim in schizophrenia research is to identify promising putative endophenotypes for use in molecular genetics studies. Recently, much of the focus has been on neurocognitive, conventional T1-weighted structural MRI, functional MRI and electrophysiological endophenotypes. Diffusion tensor imaging has emerged as another important structural neuroimaging modality in the aim to identify abnormalities in brain connectivity and diffusivity in schizophrenia, and abnormalities detected via this method may be promising candidate endophenotypes. In this article, we present the first comprehensive review of the early evidence that qualifies diffusion tensor abnormalities as potentially appropriate endophenotypes of schizophrenia.
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Affiliation(s)
- Sheena Lindsey Waters-Metenier
- Department of Psychosis Studies, King’s College London, King’s Health Partners, Institute of Psychiatry, London SE5 8AF, UK
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116
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Affiliation(s)
- Moriah E. Thomason
- Department of Pediatrics, Wayne State University School of Medicine, Detroit, Michigan 48202-3897
- Merrill Palmer Skillman Institute on Child and Family Development, Wayne State University, Detroit, Michigan 48202
| | - Paul M. Thompson
- Department of Neurology, School of Medicine, University of California, Los Angeles, Los Angeles, California 90095-1769;
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117
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Abstract
The complex phenomenology of white matter dementia and many neuropsychiatric disorders implies that they originate from involvement of distributed neural networks, and white matter neuropathology is increasingly implicated in the pathogenesis of these network disconnection syndromes. White matter disorders produce functional asynchrony of interdependent cerebral regions subserving normal cognitive and emotional functions. Accumulating evidence suggests that white matter dementia primarily reflects disturbed frontal systems connectivity, whereas disruption of frontal and temporal lobe systems is implicated in the pathogenesis of neuropsychiatric disorders. Continued study of normal and abnormal white matter promises to help resolve challenging problems in behavioral neurology and neuropsychiatry.
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Affiliation(s)
- Christopher M Filley
- Behavioral Neurology Section, University of Colorado School of Medicine, 12631 East 17th Avenue, MS B185, Aurora, CO 80045, USA.
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118
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Kong X, Ouyang X, Tao H, Liu H, Li L, Zhao J, Xue Z, Wang F, Jiang S, Shan B, Liu Z. Complementary diffusion tensor imaging study of the corpus callosum in patients with first-episode and chronic schizophrenia. J Psychiatry Neurosci 2011; 36:120-5. [PMID: 21138657 PMCID: PMC3044195 DOI: 10.1503/jpn.100041] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Abnormalities in the corpus callosum have long been implicated in schizophrenia. Previous diffusion tensor imaging (DTI) studies in patients with different durations of schizophrenia yielded inconsistent results. By comparing patients with different durations of schizophrenia, we investigated if white matter abnormalities of the corpus callosum emerge at an early stage in the illness or result from pathological progression. METHODS We recruited patients with first-episode schizophrenia, patients with chronic schizophrenia and age-, sex- and handedness-matched healthy controls. We used 2 DTI techniques (voxel-based and fibre-tracking DTI) to investigate differences in corpus callosum integrity among the 3 groups. RESULTS With both DTI techniques, significantly decreased fractional anisotropy values were identified in the genu of corpus callosum in patients with chronic schizophrenia, but not first-episode schizophrenia, compared with healthy controls. LIMITATIONS This study was cross-sectional, and the sample size was relatively small. CONCLUSION Abnormalities in the genu of the corpus callosum might be a progressive process in schizophrenia, perhaps related to disease severity and prognosis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Zhening Liu
- Correspondence to: Dr. Zhening Liu () or Dr. Shaoai Jiang (), Institute of Mental Health, Second Xiangya Hospital, Central South University, Changsha, 410011 China; Dr. Baoci Shan (), Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049 China
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119
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Is there evidence of brain white-matter abnormalities in obsessive-compulsive disorder?: a narrative review. Top Magn Reson Imaging 2011; 20:291-8. [PMID: 20859190 DOI: 10.1097/rmr.0b013e3181e8f22c] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Although several studies have confirmed the occurrence of gray-matter abnormalities in obsessive-compulsive disorder (OCD), the literature on white matter in OCD is more limited. In this study, we reviewed the role of white-matter abnormalities in the pathophysiology of OCD. METHOD We reviewed the PubMed studies investigating white-matter integrity in patients with OCD between 1980 and 2010. RESULTS Case studies of patients who developed obsessive-compulsive symptoms secondary to multiple sclerosis, cerebrovascular diseases, and paraneoplastic leucoencephalopathy and controlled studies of patients with OCD examined with neuroimaging techniques (eg, structural, diffusion, and spectroscopic magnetic resonance imaging) were all consistent with the existence of abnormalities in specific white-matter tracts (eg, internal capsule, cingulate bundle, and corpus callosum) of individuals with OCD. CONCLUSIONS Our review emphasizes that the reported white-matter alterations in OCD complement the broader gray-matter abnormalities identified and may well suggest that OCD is associated with large-scale disruption in brain systems or networks, as opposed to being a consequence of disturbances in isolated brain regions.
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120
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Wu F, Tang Y, Xu K, Kong L, Sun W, Wang F, Kong D, Li Y, Liu Y. Whiter matter abnormalities in medication-naive subjects with a single short-duration episode of major depressive disorder. Psychiatry Res 2011; 191:80-3. [PMID: 21145709 PMCID: PMC3058813 DOI: 10.1016/j.pscychresns.2010.09.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 08/27/2010] [Accepted: 09/03/2010] [Indexed: 01/18/2023]
Abstract
Convergent studies have implicated white matter abnormalities in the pathophysiology of major depressive disorder (MDD). In this study, diffusion tensor imaging (DTI) was used to examine white matter abnormalities in 23 single-episode, medication-naive MDD participants versus 21 healthy control participants. Voxel-based analysis was used to investigate whole brain white matter abnormalities in the MDD group. Fractional anisotropy was significantly lower and apparent diffusion coefficient was significantly higher in the right superior longitudinal fasciculus (SLF) within the frontal lobe, right middle frontal and left parietal white matter in the MDD group compared with the healthy group.
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Affiliation(s)
- Feng Wu
- Department of Psychiatry, The First Affiliated Hospital, China Medical University, 155 Nanjing North Street, Shenyang 110001, Liaoning, PR China
| | - Yanqing Tang
- Department of Psychiatry, The First Affiliated Hospital, China Medical University, 155 Nanjing North Street, Shenyang 110001, Liaoning, PR China
| | - Ke Xu
- Department of Radiology, The First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Shenyang 110001, Liaoning, PR China
| | - Lingtao Kong
- Department of Psychiatry, The First Affiliated Hospital, China Medical University, 155 Nanjing North Street, Shenyang 110001, Liaoning, PR China
| | - Wenge Sun
- Department of Radiology, The First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Shenyang 110001, Liaoning, PR China
| | - Fei Wang
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511, United States
| | - Dongyan Kong
- Department of Psychiatry, The First Affiliated Hospital, China Medical University, 155 Nanjing North Street, Shenyang 110001, Liaoning, PR China
- Department of Psychology, Quanzhou First Hospital, 250 East Street, Quanzhou 362000, Fujian, PR China
| | - Yanliang Li
- Department of Radiology, The First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Shenyang 110001, Liaoning, PR China
| | - Ying Liu
- Department of Psychiatry, The First Affiliated Hospital, China Medical University, 155 Nanjing North Street, Shenyang 110001, Liaoning, PR China
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121
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Abstract
AbstractThere is emerging evidence for a connection between the surface morphology of the brain and its underlying connectivity. The foundation for this relationship is thought to be established during brain development through the shaping influences of tension exerted by viscoelastic nerve fibers. The tension-based morphogenesis results in compact wiring that enhances efficient neural processing. Individuals with schizophrenia present with multiple symptoms that can include impaired thought, action, perception, and cognition. The global nature of these symptoms has led researchers to explore a more global disruption of neuronal connectivity as a theory to explain the vast array of clinical and cognitive symptoms in schizophrenia. If cerebral function and form are linked through the organization of neural connectivity, then a disruption in neural connectivity may also alter the surface morphology of the brain. This paper reviews developmental theories of gyrification and the potential interaction between gyrification and neuronal connectivity. Studies of gyrification abnormalities in children, adolescents, and adults with schizophrenia demonstrate a relationship between disrupted function and altered morphology in the surface patterns of the cerebral cortex. This altered form may provide helpful clues in understanding the neurobiological abnormalities associated with schizophrenia.
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122
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White T, Magnotta VA, Bockholt HJ, Williams S, Wallace S, Ehrlich S, Mueller BA, Ho BC, Jung RE, Clark VP, Lauriello J, Bustillo JR, Schulz SC, Gollub RL, Andreasen NC, Calhoun VD, Lim KO. Global white matter abnormalities in schizophrenia: a multisite diffusion tensor imaging study. Schizophr Bull 2011; 37:222-32. [PMID: 19770491 PMCID: PMC3004177 DOI: 10.1093/schbul/sbp088] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Emerging evidence implicates white matter (WM) abnormalities in the pathophysiology of schizophrenia. However, there is considerable heterogeneity in the presentation of WM abnormalities in the existing studies. The object of this study was to evaluate WM integrity in a large sample of patients with first-episode (FE) and chronic schizophrenia in comparison to matched control groups. Our goal was to assess whether WM findings occurred early in the illness or whether these abnormalities developed with the illness over time. METHODS Participants included 114 patients with schizophrenia (31 FE and 83 chronic patients) and 138 matched controls. High-resolution structural and diffusion tensor images were obtained on all participants. Measures of fractional anisotropy (FA) were calculated for the 4 cortical lobes and the cerebellum and brain stem. RESULTS FA was significant lower in patients vs controls in the whole brain and individually in the frontal, parietal, occipital, and temporal lobes. FA was not significantly different in the brain stem or cerebellum. FA differences were significant only in patients with chronic schizophrenia and not in the FE group. CONCLUSIONS We found global differences in the WM microstructure in patients with chronic but not FE schizophrenia. These findings suggest progressive alterations in WM microstructure.
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Affiliation(s)
- Tonya White
- Department of Child and Adolescent Psychiatry, Erasmus University, 3000 CB Rotterdam, the Netherlands.
| | | | | | | | - Stuart Wallace
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA 02129
| | - Stefan Ehrlich
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA 02129,Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02129
| | - Bryon A. Mueller
- Department of Psychiatry, University of Minnesota, Minneapolis, MN 55454
| | - Beng-Choon Ho
- Department of Psychiatry, University of Iowa, Iowa City, IA 52242
| | - Rex E. Jung
- Department of Psychology, University of New Mexico, Albuquerque, NM 87106
| | - Vincent P. Clark
- The Mind Research Network, Albuquerque, NM 87106,Department of Psychology, University of New Mexico, Albuquerque, NM 87106
| | - John Lauriello
- Department of Psychiatry, University of Missouri, Columbia, MO 65212
| | - Juan R. Bustillo
- Department of Psychiatry, University of New Mexico, Albuquerque, NM 87106
| | - S. Charles Schulz
- Department of Psychiatry, University of Minnesota, Minneapolis, MN 55454
| | - Randy L. Gollub
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA 02129,Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02129
| | | | - Vince D. Calhoun
- The Mind Research Network, Albuquerque, NM 87106,Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM 87106
| | - Kelvin O. Lim
- Department of Psychiatry, University of Minnesota, Minneapolis, MN 55454,Center for Magnetic Resonance Research, Minneapolis, MN 55455,Minneapolis Veterans Administration Medical Center, Minneapolis, MN 55417
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123
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Nazem-Zadeh MR, Davoodi-Bojd E, Soltanian-Zadeh H. Atlas-based fiber bundle segmentation using principal diffusion directions and spherical harmonic coefficients. Neuroimage 2011; 54 Suppl 1:S146-64. [PMID: 20869453 DOI: 10.1016/j.neuroimage.2010.09.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2010] [Revised: 09/09/2010] [Accepted: 09/13/2010] [Indexed: 10/19/2022] Open
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124
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Montag C, Schoene-Bake JC, Faber J, Reuter M, Weber B. Genetic variation on the BDNF gene is not associated with differences in white matter tracts in healthy humans measured by tract-based spatial statistics. GENES BRAIN AND BEHAVIOR 2010; 9:886-91. [DOI: 10.1111/j.1601-183x.2010.00626.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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125
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Bock AS, Olavarria JF, Leigland LA, Taber EN, Jespersen SN, Kroenke CD. Diffusion tensor imaging detects early cerebral cortex abnormalities in neuronal architecture induced by bilateral neonatal enucleation: an experimental model in the ferret. Front Syst Neurosci 2010; 4:149. [PMID: 21048904 PMCID: PMC2971465 DOI: 10.3389/fnsys.2010.00149] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 09/21/2010] [Indexed: 01/11/2023] Open
Abstract
Diffusion tensor imaging (DTI) is a technique that non-invasively provides quantitative measures of water translational diffusion, including fractional anisotropy (FA), that are sensitive to the shape and orientation of cellular elements, such as axons, dendrites and cell somas. For several neurodevelopmental disorders, histopathological investigations have identified abnormalities in the architecture of pyramidal neurons at early stages of cerebral cortex development. To assess the potential capability of DTI to detect neuromorphological abnormalities within the developing cerebral cortex, we compare changes in cortical FA with changes in neuronal architecture and connectivity induced by bilateral enucleation at postnatal day 7 (BEP7) in ferrets. We show here that the visual callosal pattern in BEP7 ferrets is more irregular and occupies a significantly greater cortical area compared to controls at adulthood. To determine whether development of the cerebral cortex is altered in BEP7 ferrets in a manner detectable by DTI, cortical FA was compared in control and BEP7 animals on postnatal day 31. Visual cortex, but not rostrally adjacent non-visual cortex, exhibits higher FA than control animals, consistent with BEP7 animals possessing axonal and dendritic arbors of reduced complexity than age-matched controls. Subsequent to DTI, Golgi-staining and analysis methods were used to identify regions, restricted to visual areas, in which the orientation distribution of neuronal processes is significantly more concentrated than in control ferrets. Together, these findings suggest that DTI can be of utility for detecting abnormalities associated with neurodevelopmental disorders at early stages of cerebral cortical development, and that the neonatally enucleated ferret is a useful animal model system for systematically assessing the potential of this new diagnostic strategy.
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Affiliation(s)
- Andrew S. Bock
- Department of Psychology, University of WashingtonSeattle, WA, USA
| | | | - Lindsey A. Leigland
- Advanced Imaging Research Center, Oregon Health and Science UniversityPortland, OR, USA
- Department of Behavioral Neuroscience, Oregon Health and Science UniversityPortland, OR, USA
| | - Erin N. Taber
- Advanced Imaging Research Center, Oregon Health and Science UniversityPortland, OR, USA
| | - Sune N. Jespersen
- Center of Functionally Integrative Neuroscience, Aarhus UniversityAarhus, Denmark
| | - Christopher D. Kroenke
- Advanced Imaging Research Center, Oregon Health and Science UniversityPortland, OR, USA
- Department of Behavioral Neuroscience, Oregon Health and Science UniversityPortland, OR, USA
- Oregon National Primate Research Center, Oregon Health and Science UniversityPortland, OR, USA
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126
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Abstract
Our goal was to determine whether performance variability during predictive visual tracking can provide a screening measure for mild traumatic brain injury (mTBI). Seventeen subjects with chronic postconcussive syndrome and 9 healthy control subjects were included in this study. Eye movements were recorded with video-oculography as the subject visually tracked a target that moved through a circular trajectory. We compared the variability of gaze positional errors relative to the target with the microstructural integrity of white matter tracts as measured by the fractional anisotropy (FA) parameter of diffusion tensor imaging. Gaze error variability was significantly correlated with the mean FA values of the right anterior corona radiata (ACR) and the left superior cerebellar peduncle, tracts that support spatial processing and sustenance of attention, and the genu of the corpus callosum. Because the ACR and the genu are among the most frequently damaged white matter tracts in mTBI, the correlations imply that gaze error variability during visual tracking may provide a useful screening tool for mTBI. Gaze error variability was also significantly correlated with attention and working memory measures in neurocognitive testing; thus, measurement of visual tracking performance is promising as a fast and practical screening tool for mTBI.
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127
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Bassett DS, Brown JA, Deshpande V, Carlson JM, Grafton ST. Conserved and variable architecture of human white matter connectivity. Neuroimage 2010; 54:1262-79. [PMID: 20850551 DOI: 10.1016/j.neuroimage.2010.09.006] [Citation(s) in RCA: 283] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 08/17/2010] [Accepted: 09/01/2010] [Indexed: 12/24/2022] Open
Abstract
Whole-brain network analysis of diffusion imaging tractography data is an important new tool for quantification of differential connectivity patterns across individuals and between groups. Here we investigate both the conservation of network architectural properties across methodological variation and the reproducibility of individual architecture across multiple scanning sessions. Diffusion spectrum imaging (DSI) and diffusion tensor imaging (DTI) data were both acquired in triplicate from a cohort of healthy young adults. Deterministic tractography was performed on each dataset and inter-regional connectivity matrices were then derived by applying each of three widely used whole-brain parcellation schemes over a range of spatial resolutions. Across acquisitions and preprocessing streams, anatomical brain networks were found to be sparsely connected, hierarchical, and assortative. They also displayed signatures of topo-physical interdependence such as Rentian scaling. Basic connectivity properties and several graph metrics consistently displayed high reproducibility and low variability in both DSI and DTI networks. The relative increased sensitivity of DSI to complex fiber configurations was evident in increased tract counts and network density compared with DTI. In combination, this pattern of results shows that network analysis of human white matter connectivity provides sensitive and temporally stable topological and physical estimates of individual cortical structure across multiple spatial scales.
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Affiliation(s)
- Danielle S Bassett
- Department of Physics, University of California, Santa Barbara, CA, USA.
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128
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Hale TS, Smalley SL, Walshaw PD, Hanada G, Macion J, McCracken JT, McGough JJ, Loo SK. Atypical EEG beta asymmetry in adults with ADHD. Neuropsychologia 2010; 48:3532-9. [PMID: 20705076 DOI: 10.1016/j.neuropsychologia.2010.08.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 06/22/2010] [Accepted: 08/04/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND Abnormal brain laterality (ABL) is well established in ADHD. However, its clinical specificity and association to cognitive and clinical symptoms is not yet understood. Previous studies indicate increased right hemisphere (RH) contribution in both ADHD and reading impaired samples. The current study investigates whether this ABL characteristic occurs in adults with ADHD absent comorbid language impairment. METHODS EEG beta asymmetry was compared in 35 adult ADHD subjects and 104 controls during rest and active cognition. Group differences in beta asymmetry were then further evaluated for association to linguistic and attentional abilities, as well as association to beta asymmetry measures across different brain regions. RESULTS Adults with ADHD showed pronounced rightward beta asymmetry (p=.00001) in inferior parietal regions (P8-P7) during a continuous performance task (CPT) that could not be attributed to linguistic ability. Among ADHD subjects only, greater rightward beta asymmetry at this measure was correlated with better CPT performance. Furthermore, this measure showed a lack of normal association (i.e., observed in controls) to left-biased processing in temporal-parietal (TP8-TP7) brain regions important for higher order language functions. CONCLUSION Adult ADHD involves abnormally increased right-biased contribution to CPT processing that could not be attributed to poor language ability. This appears to also involve abnormal recruitment of LH linguistic processing regions and represents an alternative, albeit less effective, CPT processing strategy. These findings suggest different pathophysiologic mechanisms likely underlie RH biased processing in ADHD and reading impaired samples.
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Affiliation(s)
- T Sigi Hale
- Department of Psychiatry and Biobehavioral Sciences, UCLA Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA 90024, USA.
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129
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Castellanos FX, Hyde Z. Diffusion tensor imaging provides new clues in adults with ADHD (Commentary on Konrad et al.). Eur J Neurosci 2010; 31:910-1. [PMID: 20374288 DOI: 10.1111/j.1460-9568.2010.07173.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- F Xavier Castellanos
- Phyllis Green and Randolph Cōwen Institute for Pediatric Neuroscience, NYU Langone Medical Center, 215 Lexington Avenue, 14th Floor, New York, NY 10016, USA
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130
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Abdallah CG, Tang CY, Mathew SJ, Martinez J, Hof PR, Perera TD, Shungu DC, Gorman JM, Coplan JD. Diffusion tensor imaging in studying white matter complexity: a gap junction hypothesis. Neurosci Lett 2010; 475:161-4. [PMID: 20371267 PMCID: PMC2862850 DOI: 10.1016/j.neulet.2010.03.070] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 03/05/2010] [Accepted: 03/29/2010] [Indexed: 01/08/2023]
Abstract
The role of the prefrontal cortex as an executive oversight of posterior brain regions raises the question of the extent to which the anterior regions of the brain interconnect with the posterior regions. The aim of this study is to test the complexity of rostral white matter tracts, which connect anterior and posterior brain regions, in comparison to caudal white matter tracts and the corpus callosum. Diffusion tensor imaging (DTI) is a modality that measures fractional anisotropy (FA). Higher white matter complexity could result in a decrease of FA, possibly through denser intersection of fiber tracts. DTI was used to determine regional FA in 9 healthy bonnet macaques (Macaca radiata). Four regions of interest were included: anterior and posterior limbs of the internal capsule, the occipital lobe white matter, and the corpus callosum. FA of the anterior limbs of the internal capsule was lowest compared to all other regions of interest (Newman-Keuls (N-K); p<0.0001), whereas FA of the corpus callosum was highest (N-K; p<0.0001). The posterior limbs of the internal capsule and the occipital white matter were not distinguishable but exhibited intermediate FA in comparison to the former (N-K; p<0.0001) and the latter (N-K; p<0.0001). The current study demonstrates that FA, a measure of white matter complexity, can vary markedly as a function of region of interest. Moreover, validation of these findings using neurohistological studies and replication in human samples appears warranted.
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Affiliation(s)
- Chadi G Abdallah
- Department of Psychiatry, Division of Neuropsychopharmacology, State University of New York, Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11023, USA.
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131
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Abstract
Neuropsychiatry is the subspecialty of psychiatry that deals with disorders at the intersection of neurology and psychiatry. Neuropsychiatric disorders are complex and incompletely understood. Neuroscience research is beginning to elucidate the biological underpinnings of many of these disorders. These advances have the potential to improve diagnosis, inform treatment selection, and facilitate development of new and better interventions.
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Affiliation(s)
- Katherine H Taber
- Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas 77030, USA
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132
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Maller JJ, Thomson RHS, Lewis PM, Rose SE, Pannek K, Fitzgerald PB. Traumatic brain injury, major depression, and diffusion tensor imaging: making connections. ACTA ACUST UNITED AC 2010; 64:213-40. [PMID: 20388528 DOI: 10.1016/j.brainresrev.2010.04.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2009] [Revised: 03/15/2010] [Accepted: 04/06/2010] [Indexed: 12/17/2022]
Abstract
UNLABELLED It is common for depression to develop after traumatic brain injury (TBI), yet despite poorer recovery, there is a lack in our understanding of whether post-TBI brain changes involved in depression are akin to those in people with depression without TBI. Modern neuroimaging has helped recognize degrees of diffuse axonal injury (DAI) as being related to extent of TBI, but its ability to predict long-term functioning is limited and has not been considered in the context of post-TBI depression. A more recent brain imaging technique (diffusion tensor imaging; DTI) can measure the integrity of white matter by measuring the directionality or anisotropy of water molecule diffusion along the axons of nerve fibers. AIM To review DTI results in the TBI and depression literatures to determine whether this can elucidate the etiology of the development of depression after TBI. METHOD We reviewed the TBI/DTI (40 articles) and depression/DTI literatures (17 articles). No articles were found that used DTI to investigate depression post-TBI, although there were some common brain regions identified between the TBI/DTI and depression/DTI studies, including frontotemporal, corpus callosum, and structures contained within the basal ganglia. Specifically, the internal capsule was commonly reported to have significantly reduced fractional anisotropy, which agrees with deep brain stimulation studies. CONCLUSION It is suggested that measuring the degree of DAI by utilizing DTI in those with or without depression post-TBI, will greatly enhance prediction of functional outcome.
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Affiliation(s)
- Jerome J Maller
- Monash Alfred Psychiatry Research Centre, The Alfred and Monash University School of Psychology and Psychiatry, Melbourne Victoria, Australia.
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133
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Davenport ND, Karatekin C, White T, Lim KO. Differential fractional anisotropy abnormalities in adolescents with ADHD or schizophrenia. Psychiatry Res 2010; 181:193-8. [PMID: 20153608 PMCID: PMC2867087 DOI: 10.1016/j.pscychresns.2009.10.012] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 09/05/2009] [Accepted: 10/23/2009] [Indexed: 11/22/2022]
Abstract
Schizophrenia and Attention-Deficit/Hyperactivity Disorder (ADHD) are associated with similar deficits in working memory, attention, and inhibition. Both disorders also involve abnormalities of white matter integrity, possibly reflecting neural communication disruptions. There are likely some regional white matter abnormalities that underlie the common cognitive impairment, though also some regional abnormalities unique to each disorder. We used diffusion tensor imaging (DTI) to compare white matter integrity, as indicated by fractional anisotropy (FA), in adolescents with schizophrenia (n=15) or ADHD (n=14) and healthy controls (n=26). Schizophrenia patients had uniquely low FA, relative to the other two groups, in bilateral cerebral peduncles, anterior and posterior corpus callosum, right anterior corona radiata, and right superior longitudinal fasciculus. ADHD patients had uniquely high FA in left inferior and right superior frontal regions. Both clinical groups had lower FA than controls in left posterior fornix. The two disorders generally demonstrated distinct patterns of abnormal connectivity suggesting that common cognitive and behavioral deficits derive from distinct sources, though the posterior fornix may be involved in both disorders. Schizophrenia was associated with abnormally low FA in widespread circuitry indicative of general connectivity disruptions, whereas ADHD was associated with abnormally high FA in frontal networks that may indicate impaired branching of fibers.
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Affiliation(s)
- Nicholas D Davenport
- Department of Psychology, University of Minnesota, Minneapolis, MN, United States.
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134
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Jung RE, Grazioplene R, Caprihan A, Chavez RS, Haier RJ. White matter integrity, creativity, and psychopathology: disentangling constructs with diffusion tensor imaging. PLoS One 2010; 5:e9818. [PMID: 20339554 PMCID: PMC2842439 DOI: 10.1371/journal.pone.0009818] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 02/16/2010] [Indexed: 11/21/2022] Open
Abstract
That creativity and psychopathology are somehow linked remains a popular but controversial idea in neuroscience research. Brain regions implicated in both psychosis-proneness and creative cognition include frontal projection zones and association fibers. In normal subjects, we have previously demonstrated that a composite measure of divergent thinking (DT) ability exhibited significant inverse relationships in frontal lobe areas with both cortical thickness and metabolite concentration of N-acetyl-aspartate (NAA). These findings support the idea that creativity may reside upon a continuum with psychopathology. Here we examine whether white matter integrity, assessed by Fractional Anisotropy (FA), is related to two measures of creativity (Divergent Thinking and Openness to Experience). Based on previous findings, we hypothesize inverse correlations within fronto-striatal circuits. Seventy-two healthy, young adult (18–29 years) subjects were scanned on a 3 Tesla scanner with Diffusion Tensor Imaging. DT measures were scored by four raters (α = .81) using the Consensual Assessment Technique, from which a composite creativity index (CCI) was derived. We found that the CCI was significantly inversely related to FA within the left inferior frontal white matter (t = 5.36, p = .01), and Openness was inversely related to FA within the right inferior frontal white matter (t = 4.61, p = .04). These findings demonstrate an apparent overlap in specific white matter architecture underlying the normal variance of divergent thinking, openness, and psychotic-spectrum traits, consistent with the idea of a continuum.
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Affiliation(s)
- Rex E Jung
- Mind Research Network, University of New Mexico, Albuquerque, New Mexico, United States of America.
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White T, Schmidt M, Karatekin C. White matter 'potholes' in early-onset schizophrenia: a new approach to evaluate white matter microstructure using diffusion tensor imaging. Psychiatry Res 2009; 174:110-5. [PMID: 19853414 PMCID: PMC2783844 DOI: 10.1016/j.pscychresns.2009.04.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2008] [Revised: 03/06/2009] [Accepted: 04/27/2009] [Indexed: 10/20/2022]
Abstract
There is considerable evidence implicating white matter abnormalities in the pathophysiology of schizophrenia. Many of the recent studies examining white matter have utilized diffusion tensor imaging (DTI) using either region of interest (ROI) or voxel-based approaches. Both voxel-based and ROI approaches are based on the assumption that the abnormalities in white matter overlap spatially. However, this is an assumption that has not been tested, and it is possible that aberrations in white matter occur in non-overlapping regions. In order to test for the presence of non-overlapping regions of aberrant white matter, we developed a novel image processing technique that evaluates for white matter 'potholes,' referring to within-subject clusters of white matter voxels that show a significant reduction in fractional anisotropy. We applied this algorithm to a group of children and adolescents with schizophrenia compared to controls and found an increased number of 'potholes' in the patient group. These results suggest that voxel-based and ROI approaches may be missing some white matter differences that do not overlap spatially. This algorithm may be also be well suited to detect white matter abnormalities in disorders such as substance abuse, head trauma, or specific neurological conditions affecting white matter.
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Affiliation(s)
- Tonya White
- Division of Child and Adolescent Psychiatry, F256/2B, University of Minnesota, Fairview University Medical Center, 2450 Riverside Avenue, Minneapolis, MN 55454, United States.
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