Midsagittal Area Of Corpus Callosum Research Articles

Altered Callosal Morphology and Connectivity in Asymptomatic Carotid Stenosis.

Carotid stenosis, even in the clinically asymptomatic stage, causes cognitive impairment, silent lesions, and hemispheric changes. The corpus callosum (CC) is crucial for hemispheric cortical integration and specialization. To examine if CC morphology and connectivity relate to cognitive decline and lesion burden in asymptomatic carotid stenosis (ACS). Retrospective, cross-sectional. 33 patients with unilaterally severe (70%) ACS and 28 demographically and comorbidity-matched controls. A publicly available healthy adult lifespan (ages between 18 and 80; n = 483) MRI dataset was also included. A 3.0 T; T1 MPRAGE and diffusion weighted gradient echo-planar imaging sequences. Structural MRI and multidomain cognitive data were obtained. Midsagittal CC area, circularity, thickness, integrity, and probabilistic tractography were calculated and correlated with cognitive tests and white matter hyperintensity. Fractional anisotropy, mean diffusivity (MD), and radial diffusivity were determined from DTI. Independent two-sample t-tests, χ2 tests, Mann-Whitney U, locally weighted scatterplot smoothing (LOWESS) curve fit, and Pearson correlation. A P value < 0.05 was considered statistically significant. Patients with ACS demonstrated significant reductions in callosal area, circularity, and thickness compared to controls. The callosal atrophy was significantly correlated with white matter hyperintensity size (r = -0.629, P < 0.001). Voxel-wise analysis of diffusion measures in the volumetric CC showed that ACS patients exhibited significantly lower fractional anisotropy and higher MD and radial diffusivity in the genu and splenium of the CC than controls. Further lifespan trajectory analysis showed that although the midsagittal callosal area, circularity, and thickness exhibited age-related decreases, the values in the ACS patients were significantly lower in all age groups. Midsagittal callosal atrophy and connectivity reflect the load of silent lesions and the severity of cognitive decline, respectively, suggesting that CC degeneration has potential to serve as an early marker in ACS. 3 TECHNICAL EFFICACY STAGE: 2.

MEASUREMENT OF MIDSAGITTAL CORPUS CALLOSUM AREA WITH THE MODIFIED CAVALIERI METHOD IN HEALTHY RIGHT- AND LEFT-HANDED TURKISH ADULTS

Background : Numerous studies have been published on the anatomy and physiology of the corpus callosum (CC). There are many contradictory studies in the literature about the changes in the size of the CC by handedness, sex, and age. Objective : This study was carried out to examine the morphometric influence of these factors (handedness, sex, and age) on the CC in healthy Turkish adults Methods : Two hundred thirty-seven normal individuals, 101 males, and 136 females, divided into 5 age groups (20-29, 30-39, 40-49, 50-59, and 60-69) were subjected to magnetic resonance imaging (MRI) study of the brain. Of the 237 subjects, 27 males and 36 females were left-handed. Midsagittal corpus callosum area (CCA) was represented by the mean ± standard deviation of the age groups in square centimeters, and also comparisons of the right- and left-handed were also represented in Table 1. For statistical evaluation, the SPSS 15.0 was used. All statistical tests were set at a 95% confidence level (p 0.05) (Table 2). Conclusion: The results showed no statistical significance of the effect of age or handedness on the surface area of the CC. However, it was statistically significant that the size of men's CC was higher than that of women. Keywords: Midsagittal corpus callosum area, modified Cavalieri method, handedness, Turkish adults, magnetic resonance imaging.

Increased Serum C-reactive Protein and Corpus Callosum Alterations in Older Adults.

Chronic systemic low-grade inflammation is associated with aging, but little is known on whether age-related inflammation affects brain structure, particularly white matter. The current study tested the hypothesis that in older adults without dementia, higher serum levels of high-sensitivity C-reactive protein (hs-CRP) are associated with reduced corpus callosum (CC) areas. French community-dwelling subjects (ESPRIT study) aged 65 and older (N=101) underwent hs-CRP testing and structural magnetic resonance imaging (MRI). Multiple linear regression models were carried out. In the unadjusted model, higher hs-CRP level was significantly associated with smaller anterior, mid, and total midsagittal CC areas, but not with the posterior CC area. These associations were independent of demographic characteristics and intracranial volume. After adjustment for body mass index, diabetes, inflammation-related chronic pathologies and white matter lesions (WML), only the associations between hs-CRP level and smaller anterior and total midsagittal CC areas were still significant, although weaker. These findings suggest that low-grade inflammation is associated with CC structural integrity alterations in older adults independently of physical or neuropsychiatric pathologies.

Partial Agenesis and Hypoplasia of the Corpus Callosum in Idiopathic Autism.

To test the hypothesis that developmental anomalies of the corpus callosum (CC), contribute to the pathogenesis of autism, we characterized the type, topography, and severity of CC pathology corresponding to reduced CC areas that are detected by magnetic resonance imaging in the brains of 11 individuals with autism and 11 controls. In the brains of 3 autistic subjects, partial CC agenesis resulted in complete or partial lack of interhemispheric axonal connections in CC segments III-V. In these cases, a combination of focal agenesis and uniform axonal deficit caused reduction of CC areas by 37%, of axon numbers by 62%, and of the numerical density of axons by 39%. In the CC of 8 autistic subjects without agenesis, there was an 18% deficit of the midsagittal CC area, 48.4% deficit of axon numbers, and 37% reduction of the numerical density of axons. The significantly thinner CC, reduced CC area, and uniform axonal deficit in all autistic subjects were classified as CC hypoplasia. Thus, the byproduct of partial CC agenesis and hypoplasia is reduction of axonal connections between cortical areas known to be involved in behavioral alterations observed in people with autism.

Sex-related difference in human white matter volumes studied: Inspection of the corpus callosum and other white matter by VBM

It has been contended that any observed difference of the corpus callosum (CC) size between men and women is not sex-related but brain-size-related. A recent report, however, showed that the midsagittal CC area was significantly larger in women in 37 brain-size-matched pairs of normal young adults. Since this constituted strong evidence of sexual dimorphism and was obtained from publicly available data in OASIS, we examined volume differences within the CC and in other white matter using voxel-based morphometry (VBM). We created a three-dimensional region of interest of the CC and measured its volume. The VBM statistics were analyzed by permutation test and threshold-free cluster enhancement (TFCE) with the significance levels at FWER < 0.05. The CC volume was significantly larger in women in the same 37 brain-size-matched pairs. We found that the CC genu was the subregion showing the most significant sex-related difference. We also found that white matter in the bilateral anterior frontal regions and the left lateral white matter near to Broca’s area were larger in women, whereas there were no significant larger regions in men. Since we used brain-size-matched subjects, our results gave strong volumetric evidence of localized sexual dimorphism of white matter.

Midsagittal corpus callosum area and conversion to multiple sclerosis after clinically isolated syndrome: A multicentre Australian cohort study.

Patients presenting with clinically isolated syndrome (CIS) may proceed to clinically definite multiple sclerosis (CDMS). Midsagittal corpus callosum area (CCA) is a surrogate marker for callosal atrophy, and can be obtained from a standard MRI study. This study explores the relationship between CCA measured at CIS presentation (baseline) and at 5years post presentation, with conversion from CIS to CDMS. The association between CCA and markers of disability progression is explored. Corpus callosum area was measured on MRI scans at presentation and 5-year review following diagnosis of a first demyelinating event, or evidence of progressive MS, in 143 participants in the Ausimmune/AusLong Study. Relationships between CCA (at baseline and follow-up) and clinical outcomes were assessed. Mean CCA at baseline study was 6.63cm2 (SD 1.01). Patients who converted to MS by 5-year review (n=100) had a significantly smaller mean CCA at follow-up (6.22 vs. 6.74, P=0.007). Greater CCA reduction was associated with higher annualized relapse rate over follow-up. Baseline CCA obtained from standard MRI protocols may be compared with subsequent MRI examinations as a surrogate for neurodegeneration and cerebral atrophy in patients with MS. This study demonstrates an association between CCA and disability in individuals presenting with CIS who convert to MS.

Cognitive event-related potentials in multiple sclerosis: Correlation with MRI and neuropsychological findings

BackgroundCognitive event-related potentials (ERPs) have been previously correlated with T2 lesion load (Τ2LL) in patients with multiple sclerosis (MS). It is currently unknown, however, whether ERPs also correlate with brain atrophy or the presence of T1 hypointense lesions (“black holes”) which reflect tissue destruction and axonal loss. The primary aim of the current study is to explore the effect of neuroradiological parameters such as brain atrophy, T1 and T2 lesion load on auditory ERPs in MS patients. In addition, we correlated cognitive impairment with neurophysiological (ERP) and neuroradiological (MRI) variables and investigated whether a combination of ERP and MRI parameters is capable of distinguishing patients suffering from secondary progressive (SP), primary progressive (PP) and relapsing-remitting (RR) MS. Materials and methodsThe study sample consisted of fifty nine MS patients (mean age±SD: 37.82±1.38 years; average disease duration: 6.76±5.3 years) and twenty six age-matched controls (mean age±SD: 41.42±15.39 years). The patients’ EDSS and NRS scores were 3.77±2.14 (range: 1–7.5) and 75.88±11.99 (range: 42–94) respectively. ERPs were recorded using the auditory “odd-ball” paradigm. T1 and T2 lesions were automatically segmented using an edge-finding tool and total lesion volumes were calculated. MRI measures of brain atrophy included third ventricle width (THIRDVW) and the ratio of mid-sagittal corpus callosum area to the mid-sagittal intracranial skull surface area (CC/MISS). Statistical analysis was performed using multiple regression, principal component (PCA) and discriminant analysis. ResultsT1 lesion load emerged as the most significant predictor of P300 and N200 latency. The rest of the endogenous ERPs parameters (P300 amplitude, N200 amplitude) were not significantly correlated with the MRI variables. PCA of pooled neuroradiological and neurophysiological markers suggested that four components accounted for 64.6% of the total variability. Discriminant analysis based on ERP & MRI markers classified correctly 79.63% of patients in RR, PP and SP subgroups. ConclusionT1 lesion load is the most significant MRI correlate of auditory ERPs in MS patients. Importantly, ERPs in combination with MRI variables can be usefully employed for distinguishing patients with different subtypes of MS.

EXAMINER Executive Function Battery and Neurologic Morbidity in Pediatric Sickle Cell Disease

Sickle cell disease (SCD) is blood disorder with a high risk for cerebral vascular morbidities that impact neurocognitive functioning. Specific cognitive abilities are known to be more sensitive to neurologic effects of SCD than IQ scores, yet there is little consensus about which measures to use to assess neurocognitive functioning. We evaluated the ability of the Executive Abilities: Methods and Instruments for Neurobehavioral Evaluation and Research (EXAMINER) Battery to detect neurologic effects in SCD. Thirty-two youth with SCD and sixty demographically-matched comparison youth completed the EXAMINER Battery and selected tests from the Woodcock-Johnson Tests of Cognitive Ability, 3rd edition (WJ-III). Neurologic severity was examined via clinical history for morbidities and midsagittal corpus callosum (CC) area. Results indicated cognitive performance decreased with increasing neurologic morbidity across all cognitive measures; two of four EXAMINER factors were related to CC area. The association with clinical history and midsagittal CC area appeared at least as large for the Examiner Battery scores as for the WJ-III measures. The Examiner Battery showed sensitivity to neurologic history and white matter effects in SCD; this new measure compares favorably to established measures of disease-related neurocognitive effects, but would benefit from further development.

Automated segmentation of corpus callosum in MRI scans: application to tracking Alzheimer's disease progression

Event Abstract Back to Event Automated segmentation of corpus callosum in MRI scans: application to tracking Alzheimer's disease progression Babak A. Ardekani1*, Sang Han Lee1 and Alvin H. Bachman1 1 The Nathan S. Klein Institute for Psychiatric Research, Medical Physics, United States Background: The mid-sagittal cross-section of the corpus callosum (CC) has been examined extensively using MRI in various pathologies including Alzheimer’s disease (AD). Hitherto, the majority of MRI studies of CC have used manual or semi-automatic tracings on a representative mid-sagittal slice. This approach is time-consuming, prone to errors, and expensive to carry out. Here, a fully automated mutli-atlas-based algorithm is presented for the segmentation of CC mid-sagittal cross-sectional area. The method is applied to healthy controls (HC) and AD patients in the Open Access Series of Brain Imaging Studies (OASIS) database. Methods: The mid-sagittal plane and the anterior and posterior commissures were detected automatically on 628 structural MRI scans. Using this information, a mid-sagittal slice was reconstructed and the CC was outlined manually on all scans. These data were used as atlases for automated segmentation using a novel mutli-atlas label fusion approach. The algorithm was then applied to 563 OASIS scans. The total mid-sagittal CC area (CCA), the CC circularity (CIR), and the CC thickness profile were measured and analyzed in relation to subjects’ sex, age, brain size, and AD diagnosis. Results: The algorithm was able to segment CC with a success rate of about 95%. Negative correlations were found between age and both CCA and CIR. There was a positive correlation between CCA and brain size, however, the CIR decreased with brain size. Controlling for age and brain size, CCA was larger and CIR was smaller in females. Controlling for age, sex, and brain size, CCA and CIR were both smaller in AD relative to HC. However, only CIR was significantly different between very mild and mild AD groups, being smaller in the latter. The rates of change of CCA and CIR were both significantly more negative in AD relative to HC. However, only the rate of change of CIR was different between very mild and mild AD, being more negative in the latter. Analysis of CC thickness profiles showed that the CC in AD is thinner that HC throughout the length of the CC but more significantly at the splenium and the genu. Discussion: This research offers a fast, robust, accurate, and fully automatic CC segmentation program (‘yuki’) available publicly (www.nitrc.org/projects/art). We confirmed the hotly debated existence of a sexual dimorphism in CC size and shape. We showed the circularity of the CC to be a more effective measure than its size for tracking AD progression. Keywords: MRI, Corpus Callosum, image segmentation, Alzheimer’s disease, Sex Conference: ACNS-2013 Australasian Cognitive Neuroscience Society Conference, Clayton, Melbourne, Australia, 28 Nov - 1 Dec, 2013. Presentation Type: Poster Topic: Other Citation: Ardekani BA, Lee S and Bachman AH (2013). Automated segmentation of corpus callosum in MRI scans: application to tracking Alzheimer's disease progression. Conference Abstract: ACNS-2013 Australasian Cognitive Neuroscience Society Conference. doi: 10.3389/conf.fnhum.2013.212.00057 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 15 Oct 2013; Published Online: 25 Nov 2013. * Correspondence: Dr. Babak A Ardekani, The Nathan S. Klein Institute for Psychiatric Research, Medical Physics, New York, New York, 12518, United States, Ardekani@nki.rfmh.org Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Babak A Ardekani Sang Han Lee Alvin H Bachman Google Babak A Ardekani Sang Han Lee Alvin H Bachman Google Scholar Babak A Ardekani Sang Han Lee Alvin H Bachman PubMed Babak A Ardekani Sang Han Lee Alvin H Bachman Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Corpus callosum area in children and adults with autism

Despite repeated findings of abnormal corpus callosum structure in autism, the developmental trajectories of corpus callosum growth in the disorder have not yet been reported. In this study, we examined corpus callosum size from a developmental perspective across a 30-year age range in a large cross-sectional sample of individuals with autism compared to a typically developing sample. Midsagittal corpus callosum area and the 7 Witelson subregions were examined in 68 males with autism (mean age 14.1 years; range 3–36 years) and 47 males with typical development (mean age 15.3 years; range 4–29 years). Controlling for total brain volume, increased variability in total corpus callosum area was found in autism. In autism, increased midsagittal areas were associated with reduced severity of autism behaviors, higher intelligence, and faster speed of processing (p=0.003, p=0.011, p=0.013, respectively). A trend toward group differences in isthmus development was found (p=0.029, uncorrected). These results suggest that individuals with autism benefit functionally from increased corpus callosum area. Our cross-sectional examination also shows potential maturational abnormalities in autism, a finding that should be examined further with longitudinal datasets.

Sociability and brain development in BALB/cJ and C57BL/6J mice

Sociability—the tendency to seek social interaction—propels the development of social cognition and social skills, but is disrupted in autism spectrum disorders (ASD). BALB/cJ and C57BL/6J inbred mouse strains are useful models of low and high levels of juvenile sociability, respectively, but the neurobiological and developmental factors that account for the strains’ contrasting sociability levels are largely unknown. We hypothesized that BALB/cJ mice would show increasing sociability with age but that C57BL/6J mice would show high sociability throughout development. We also hypothesized that littermates would resemble one another in sociability more than non-littermates. Finally, we hypothesized that low sociability would be associated with low corpus callosum size and increased brain size in BALB/cJ mice. Separate cohorts of C57BL/6J and BALB/cJ mice were tested for sociability at 19-, 23-, 31-, 42-, or 70-days-of-age, and brain weights and mid-sagittal corpus callosum area were measured. BALB/cJ sociability increased with age, and a strain by age interaction in sociability between 31 and 42 days of age suggested strong effects of puberty on sociability development. Sociability scores clustered according to litter membership in both strains, and perinatal litter size and sex ratio were identified as factors that contributed to this clustering in C57BL/6J, but not BALB/cJ, litters. There was no association between corpus callosum size and sociability, but smaller brains were associated with lower sociability in BALB/cJ mice. The associations reported here will provide directions for future mechanistic studies of sociability development.

Fast, fully automated MRI-based measurement of the human corpus callosum

Event Abstract Back to Event Fast, fully automated MRI-based measurement of the human corpus callosum Timothy J Herron1*, Xiaojian Kang2, And U Turken3 and David L Woods4 1 US Veterans Affairs, Neurology, United States 2 UC Davis, Neurology & Neuroscience, United States 3 US Veterans Affairs Research, United States 4 US Veterans Affairs, United States We present a stand-alone open-source MatLab software package, C8, which measures midsagittal cross-sectional thickness and area of the human corpus callosum from high-resolution T1 in vivo MR images. C8 quickly extracts and measures the callosum using segmented, affine normalized brains as input. Areas are computed for geometrically defined callosal compartments according to several different extant compartment schemes. Thickness is sampled along a median line within the callosum according to three methods of spacing the samples: equal angle, equal-distance, and equal-area. Coregistered accessory input images have values sampled along the median line and near the edges of the callosum. The algorithm’s performance was tested using the high-quality OASIS image database [www.oasis-brains.org] and showed C8 producing consistent, reliable callosal measurement estimates over repeated scans and with values comparable to manually-segmented callosa. We used 1000+ medium quality T1 images from the 1000 Functional Connectomes Project [fcon_1000.projects.nitrc.org] to evaluate between group differences in measured callosum values and regional effects of age and gender on thickness measures. We also sampled normalized T1 values along the callosum to capture regional variation. A second analysis used the OASIS database young normals plus our own high-quality set of T1 images from young normals (~290 subjects total) in order to correlate callosal thickness/area with regional cortical gray matter thickness and area in 34 cortical ROIs defined using FreeSurfer [surfer.nmr.mgh.harvard.edu]. We found that regional callosal area (and callosal thickness to a lesser extent), correlate positively with regional cortical area but not with regional cortical thickness. Figure 1 Keywords: computational neuroscience, Neuroimaging Conference: 4th INCF Congress of Neuroinformatics, Boston, United States, 4 Sep - 6 Sep, 2011. Presentation Type: Poster Presentation Topic: Computational neuroscience Citation: Herron T, Kang X, Turken A and Woods D (2011). Fast, fully automated MRI-based measurement of the human corpus callosum. Front. Neuroinform. Conference Abstract: 4th INCF Congress of Neuroinformatics. doi: 10.3389/conf.fninf.2011.08.00108 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 17 Oct 2011; Published Online: 19 Oct 2011. * Correspondence: Dr. Timothy J Herron, US Veterans Affairs, Neurology, Martinez, United States, tjherron@ebire.org Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Timothy J Herron Xiaojian Kang And U Turken David L Woods Google Timothy J Herron Xiaojian Kang And U Turken David L Woods Google Scholar Timothy J Herron Xiaojian Kang And U Turken David L Woods PubMed Timothy J Herron Xiaojian Kang And U Turken David L Woods Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Callosal microstructural abnormalities in Alzheimer's disease and alcoholism: same phenotype, different mechanisms

Magnetic resonance (MRI) and diffusion tensor imaging (DTI) data were acquired in 13 Alzheimer's disease (AD) patients, 15 elderly alcoholics, and 32 elderly controls. Midsagittal area, length, dorsoventral height, fractional anisotropy (FA), and mean diffusivity (MD) of the total corpus callosum and volume of the lateral ventricles were measured; area, FA, and MD were also determined for the callosal genu, body, and splenium. On DTI, both patient groups had lower FA and higher MD than controls in all callosal regions. On MRI, both patient groups had smaller genu than controls; additional size deficits were present in the alcoholism group's callosal body and the AD group's splenium. The callosal arch was higher in the AD but not the alcoholic group compared with controls. The two patient groups had larger ventricles than controls, and the AD group had larger ventricles than the alcoholic group. Callosal area correlated with its height, and callosal FA and MD correlated with ventricular volume in AD, whereas callosal area correlated only with FA in alcoholics. In AD, the disruption of the callosal integrity, which was associated with distorted callosal shape, was related to ventricular dilation, which has been shown in twin studies to be under a multitude of genetic, polygenetic, and environmental influences. Conversely, in alcoholism, disruption of callosal microstructural integrity was related to shrinkage of the corpus callosum itself.

Total Brain Volume and Corpus Callosum Size in Medication-Naïve Adolescents and Young Adults with Autism Spectrum Disorder

Increased total brain volume (TBV) has been reported for children with autism spectrum disorder (ASD) but studies in older ASD subjects have been contradictory. Similarly, studies of corpus callosum (CC) area in ASD differ with regard to inclusion criteria, age, and IQ. In the present study, TBV, gray matter (GM), and white matter (WM) volume as well as midsagittal CC area were compared between 15 medication-naïve, high-functioning adolescent and young adult ASD subjects and 15 healthy control individuals, and correlations with visuomotor coordination and imitation abilities were explored. In addition, computational surface-based methods were implemented to encode callosal thickness at high spatial resolution. Total brain volume, GM, and WM were increased and CC area was decreased in ASD subjects, a finding that was predominantly due to ASD subjects with lower IQ. Positive correlations of IQ with volume measures were observed only in control subjects. Autism spectrum disorder subjects showed reduced thickness in the posterior part of the CC. White matter volume showed a trend for negative correlation with dynamic balance and imitation abilities across groups. This study replicates previous structural magnetic resonance imaging (MRI) findings in ASD, emphasizes the role of IQ differences, and adds some evidence for functional implications of structural findings.

Preliminary Evidence for Sensitive Periods in the Effect of Childhood Sexual Abuse on Regional Brain Development

Preliminary Evidence for Sensitive Periods in the Effect of Childhood Sexual Abuse on Regional Brain Development

Diffusion tensor quantification of the macrostructure and microstructure of human midsagittal corpus callosum across the lifespan

The midsagittal cross-sectional area of the human corpus callosum (CC) has been used by many researchers as a marker of development, natural aging, and neurodegenerative and acquired pathologies. The availability of non-invasive MRI methods for quantifying the macrostructural and microstructural organization of the CC would help to clarify the CC contribution to behavior and cognition in both health and disease. In this report, we extended and validated the ability of a recently described semi-automated diffusion tensor imaging tissue segmentation method to utilize the high orientation contrast of the CC on diffusion tensor imaging. Using a cohort of healthy right-handed children and adults aged 7-59 years, we show gender-independent non-linear (quadratic) and strongly correlated growth trends in the CC area and the corresponding diffusion tensor fractional anisotropy (r = 0.67; P < 1 x 10(-10)). Our results provide preliminary evidence that diffusion tensor anisotropy in the living CC may be related to the number of small myelinated fibers.

Reduced Relationship to Cortical White Matter Volume Revealed by Tractography-Based Segmentation of the Corpus Callosum in Young Children With Developmental Delay

Objective: The corpus callosum is the primary anatomical substrate for interhemispheric communication, which is important for a range of adaptive and cognitive behaviors in early development. Previous studies that have measured the corpus callosum in developmental populations have been limited by the use of rather arbitrary methods of subdividing the corpus callosum. The purpose of this study was to measure the corpus callosum in a clinical group of developmentally delayed children using a subdivision that more accurately reflected the anatomical properties of the corpus callosum. Method: The authors applied tractography to subdivide the corpus callosum into regions corresponding to the cortical regions to and from which its fibers travel in a clinical group of very young children with developmental delay, a precursor to general mental retardation, in comparison with typically developing children. Results: The data demonstrate that the midsagittal area of the entire corpus callosum is reduced in children presenting with developmental delay, reflected in the smaller area of each of the fiber-based callosal subdivisions. In addition, while the area of each subdivision was strongly and significantly correlated with the corresponding cortical white matter volume in comparison subjects, this correlation was prominently absent in the developmentally delayed group. Conclusions: A fiber-based subdivision successfully separates lobar regions of the corpus callosum, and the areas of these regions distinguish a developmentally delayed clinical group from the comparison group. This distinction was evident both in the area measurements themselves and in their correlation to the white matter volumes of the corresponding cortical lobes.

Reduced Relationship to Cortical White Matter Volume Revealed by Tractography-Based Segmentation of the Corpus Callosum in Young Children With Developmental Delay

The corpus callosum is the primary anatomical substrate for interhemispheric communication, which is important for a range of adaptive and cognitive behaviors in early development. Previous studies that have measured the corpus callosum in developmental populations have been limited by the use of rather arbitrary methods of subdividing the corpus callosum. The purpose of this study was to measure the corpus callosum in a clinical group of developmentally delayed children using a subdivision that more accurately reflected the anatomical properties of the corpus callosum. The authors applied tractography to subdivide the corpus callosum into regions corresponding to the cortical regions to and from which its fibers travel in a clinical group of very young children with developmental delay, a precursor to general mental retardation, in comparison with typically developing children. The data demonstrate that the midsagittal area of the entire corpus callosum is reduced in children presenting with developmental delay, reflected in the smaller area of each of the fiber-based callosal subdivisions. In addition, while the area of each subdivision was strongly and significantly correlated with the corresponding cortical white matter volume in comparison subjects, this correlation was prominently absent in the developmentally delayed group. A fiber-based subdivision successfully separates lobar regions of the corpus callosum, and the areas of these regions distinguish a developmentally delayed clinical group from the comparison group. This distinction was evident both in the area measurements themselves and in their correlation to the white matter volumes of the corresponding cortical lobes.

Altered Interhemispheric Connectivity in Individuals With Tourette's Disorder

The corpus callosum is the major commissure connecting the cerebral hemispheres. Prior evidence suggests involvement of the corpus callosum in the pathophysiology of Tourette's disorder. The authors assessed corpus callosum size and anatomical connectivity across the cerebral hemispheres in persons with Tourette's disorder. The size of the corpus callosum was determined on the true midsagittal slices of reformatted, high-resolution magnetic resonance imaging scans and compared across groups in a cross-sectional case-control study of 158 subjects with Tourette's disorder and 121 healthy comparison subjects, ages 5-65 years. In the context of increasing midsagittal corpus callosum area from childhood to age 30 years, children with Tourette's disorder had smaller overall corpus callosum size, whereas adults with Tourette's disorder on average had larger corpus callosum size, yielding a prominent interaction of diagnosis with age. Corpus callosum size correlated positively with tic severity. Corpus callosum size also correlated inversely with dorsolateral prefrontal and orbitofrontal cortical volumes in both the subjects with Tourette's disorder and the comparison subjects, but the magnitudes of the correlations were significantly greater in the group with Tourette's disorder. The effects of medication and comorbid illnesses had no appreciable influence on the findings. Given prior evidence for the role of prefrontal hypertrophy in the regulation of tic symptoms, the current findings suggest that neural plasticity may contribute to smaller corpus callosum size in persons with Tourette's disorder, which thereby limits neuronal trafficking across the cerebral hemispheres and reduces input to cortical inhibitory interneurons within the prefrontal cortices. Reduced inhibitory input may in turn enhance prefrontal excitation, thus helping to control tics and possibly contributing to the cortical hyperexcitatibility reported previously in patients with Tourette's disorder.

Sex differences in the corpus callosum of patients with schizophrenia

The corpus callosum (CC) has been of interest in schizophrenia research because of its possible role in reduced lateralization and because of its sexually dimorphic characteristics. The literature has been replete with structural brain studies that have yielded equivocal results because of failure to address sex differences, handedness, and overall reductions in total brain volume (TBV) associated with schizophrenia. We performed midsagittal corpus callosum area MRI measurements on 71 chronically ill patients with schizophrenia (52 males, 19 females) and 67 controls (49 males, 18 females) using a semiautomated analytic technique subdividing the corpus callosum into five segments. Consistent with a meta-analysis [J. Neurol., Neurosurg. Psychiatry 58 (1995) 457], reductions in total CC area (after controlling for TBV and age) were found in schizophrenia patients relative to controls. However, our effect size, though not statistically significant, was −0.33 compared to −0.18 for the meta-analysis, indicating greater reductions in total CC area in our group of patients. Statistical significance was achieved only in male patients versus male controls (effect size=−0.50). The effect size remained the same when only right-handers were included in the analysis; thus, handedness did not account for this result. CC size was not related to psychiatric symptoms nor cognitive functioning in this group of patients.