Posterior Corpus Callosum Research Articles

The impact of cancer and chemotherapy during pregnancy on child neurodevelopment: A multimodal neuroimaging analysis.

BackgroundThis study applies multimodal MRI to investigate neurodevelopment in nine-year-old children born to cancer-complicated pregnancies.MethodsIn this cohort study, children born after cancer-complicated pregnancies were recruited alongside 1:1 matched controls regarding age, sex and gestational age at birth (GA). Multimodal MRI was used to investigate whole-brain and subcortical volume, cortical structure (using surface-based morphometry), white matter microstructure (using fixel-based analysis) and functional connectivity (using resting-state blood-oxygen-level-dependant signal correlations). Graph theory probed whole-brain structural and functional organization. For each imaging outcome we conducted two group comparisons: 1) children born after cancer-complicated pregnancies versus matched controls, and 2) the subgroup of children with prenatal chemotherapy exposure versus matched controls. In both models, we used the covariate of GA and the group-by-GA interaction, using false-discovery-rate (FDR) or family-wise-error (FWE) correction for multiple comparisons. Exploratory post-hoc analyses investigated the relation between brain structure/function, neuropsychological outcome and maternal oncological/obstetrical history.FindingsForty-two children born after cancer-complicated pregnancies were included in this study, with 30 prenatally exposed to chemotherapy. Brain organization and functional connectivity were not significantly different between groups. Both cancer and chemotherapy in pregnancy, as compared to matched controls, were associated with a lower travel depth, indicating less pronounced gyrification, in the left superior temporal gyrus (pFDR ≤ 006), with post-hoc analysis indicating platinum derivatives during pregnancy as a potential risk factor (p = .028). Both cancer and chemotherapy in pregnancy were related to a lower fibre cross-section (FCS) and lower fibre density and cross-section (FDC) in the posterior corpus callosum and its tapetal fibres, compared to controls. Higher FDC in the chemotherapy subgroup and higher FCS in the whole study group were observed in the anterior thalamic radiations. None of the psycho-behavioural parameters correlated significantly with any of the brain differences in the study group or chemotherapy subgroup.InterpretationPrenatal exposure to maternal cancer and its treatment might affect local grey and white matter structure, but not functional connectivity or global organization. While platinum-based therapy was identified as a potential risk factor, this was not the case for chemotherapy in general.FundingThis project has received funding from the European Union's Horizon 2020 research and innovation program (European Research council, grant no 647,047), the Foundation against cancer (Stichting tegen kanker, grant no. 2014–152) and the Research Foundation Flanders (FWO, grants no. 11B9919N, 12ZV420N)

Clinical features and brain structural changes in magnetic resonance imaging in Alzheimer's disease patients with apathy.

Background: Apathy is common in Alzheimer’s disease (AD) patients. However, its relation with other clinical symptoms in AD and brain structural changes in magnetic resonance imaging is unclear.Results: Compared with AD with no apathy group, cognitive function and activities of daily living were significantly impaired and neuropsychiatric symptoms were obviously presented in AD with apathy group (P<0.05). The frequency of Apolipoprotein E genotypes was not significantly different (P>0.05). Correlation analyses and multiple linear analyses revealed that thickness of left temporal pole and volume of posterior corpus callosum were significantly and negatively correlated with Modified Apathy Estimation Scale score in AD patients (P<0.05).Conclusions: Apathy with AD is positively correlated with cognitive impairment, neuropsychiatric symptoms and poor activities of daily living. Atrophy of left temporal pole and posterior corpus callosum presented by MRI is positively related with apathy of AD.Methods: In this study, 137 AD patients were recruited and divided into AD with apathy group and AD with no apathy group according to Modified Apathy Estimation Scale score. We evaluated patients’ cognitive function, neuropsychiatric symptoms and activities of daily living, detected the frequency of Apolipoprotein E genotypes and measured cortical thickness and volume by magnetic resonance imaging (MRI).

Prospective Study Examining the Effects of Extreme Drinking on Brain Structure in Emerging Adults.

Emerging adulthood is a critical neurodevelopment period in which extreme drinking has a potentially pronounced neurotoxic effect. Therefore, extreme drinking, even a single episode, could be particularly harmful to the developing brain's structure. Relatedly, heavy alcohol use in emerging adults has been associated with structural brain damage, especially in the corpus callosum. However, it is unclear whether and how much a single extreme drinking episode would affect brain morphometry. For the first time in the literature, the current study prospectively examined the impact of an extreme drinking episode (i.e., twenty-first birthday celebration) on the brain morphometry of emerging adults immediately following their birthday celebration (n=50) and approximately 5weeks post-birthday celebration (n=29). We found evidence that a single extreme drinking episode was associated with structural changes immediately post-birthday celebration. Specifically, higher twenty-first birthday estimated blood-alcohol concentration was associated with decreased volume of the posterior and central corpus callosum immediately post-birthday celebration. This extreme drinking episode was not associated with further structural changes, or recovery, 5weeks post-twenty-first birthday celebration. Overall, results suggest that a single episode of heavy drinking in emerging adulthood may be associated with immediate structural changes of the corpus callosum. Thus, emerging adulthood, which is characterized by high rates of extreme drinking, could be a critical period for targeted prevention and intervention.

Transient Hypothyroidism During Lactation Alters the Development of the Corpus Callosum in Rats. An in vivo Magnetic Resonance Image and Electron Microscopy Study.

Magnetic resonance imaging (MRI) data of children with late diagnosed congenital hypothyroidism and cognitive alterations such as abnormal verbal memory processing suggest altered telencephalic commissural connections. The corpus callosum (CC) is the major inter-hemispheric commissure that contra-laterally connects neocortical areas. However, in late diagnosed neonates with congenital hypothyroidism, the possible effect of early transient and chronic postnatal hypothyroidism still remains unknown. We have studied the development of the anterior, middle and posterior CC, using in vivo MRI and electron microscopy in hypothyroid and control male rats. Four groups of methimazole (MMI) treated rats were studied. One group, as a model for early transient hypothyroidism, was MMI-treated from postnatal day (P) 0 to P21; some of these rats were also treated with L-thyroxine (T4) from P15 to 21. Another group modeling chronic hypothyroid, were treated with MMI from P0 to 150 and from embryonic day 10 to P170. The results obtained from these groups were compared with same age control rats. The normalized T2 signal obtained using MRI was higher in MMI-treated rats and correlated with a low number and percentage of myelinated axons. The number and density of myelinated axons decreased in transient and chronic hypothyroid rats at P150. The g-ratio (inner to outer diameter ratio) and the estimated conduction velocity of myelinated axons were similar between MMI-treated and controls, but the conduction delay decreased in the posterior CC of MMI-treated rats compared to controls. These data show that early postnatal transient and chronic hypothyroidism alters CC maturation in a way that may affect the callosal transfer of information. These alterations cannot be reversed after delayed T4-treatment. Our data support the findings of neurocognitive delay in late T4-treated children with congenital hypothyroidism.

A genome-wide association study of interhemispheric theta EEG coherence: implications for neural connectivity and alcohol use behavior.

Aberrant connectivity of large-scale brain networks has been observed among individuals with alcohol use disorders (AUDs) as well as in those at risk, suggesting deficits in neural communication between brain regions in the liability to develop AUD. Electroencephalographical (EEG) coherence, which measures the degree of synchrony between brain regions, may be a useful measure of connectivity patterns in neural networks for studying the genetics of AUD. In 8810 individuals (6644 of European and 2166 of African ancestry) from the Collaborative Study on the Genetics of Alcoholism (COGA), we performed a Multi-Trait Analyses of genome-wide association studies (MTAG) on parietal resting-state theta (3-7 Hz) EEG coherence, which previously have been associated with AUD. We also examined developmental effects of GWAS findings on trajectories of neural connectivity in a longitudinal subsample of 2316 adolescent/young adult offspring from COGA families (ages 12-30) and examined the functional and clinical significance of GWAS variants. Six correlated single nucleotide polymorphisms located in a brain-expressed lincRNA (ENSG00000266213) on chromosome 18q23 were associated with posterior interhemispheric low theta EEG coherence (3-5 Hz). These same variants were also associated with alcohol use behavior and posterior corpus callosum volume, both in a subset of COGA and in the UK Biobank. Analyses in the subsample of COGA offspring indicated that the association of rs12954372 with low theta EEG coherence occurred only in females, most prominently between ages 25 and 30 (p < 2 × 10-9). Converging data provide support for the role of genetic variants on chromosome 18q23 in regulating neural connectivity and alcohol use behavior, potentially via dysregulated myelination. While findings were less robust, genome-wide associations were also observed with rs151174000 and parieto-frontal low theta coherence, rs14429078 and parieto-occipital interhemispheric high theta coherence, and rs116445911 with centro-parietal low theta coherence. These novel genetic findings highlight the utility of the endophenotype approach in enhancing our understanding of mechanisms underlying addiction susceptibility.

Childhood autism associated with neurological manifestations and corpus callosum hypoplasia: literature review and clinical cases

Aim. To consolidate literature data and to demonstrate rare hereditary neurogenetic syndromes with various neuropsychiatric manifestations and a corpus callosum (CC) structurally reduced in size.Material and methods. Full text data from scholarly journals were used for the review. Mental and neurological disorders were studied in two examined patients with neurogenetic syndromes. A brain MRI showed that it was accompanied with CC hypoplasia. We conducted comprehensive analysis of anamnestic data as well as medical genetic, neurological, psychopathological, pathopsychological, laboratory, and instrumental examinations.Results. The presented observations testified to a burdened obstetric history, dysfunctional ante-, intra-, and postnatal periods. The first patient with the Wolf-Hirschhorn syndrome was diagnosed with atypical autism associated with severe mental retardation, lack of verbal means of communication, motor stereotypes, structural focal epilepsy, cerebral palsy (CP), severe systemic speech underdevelopment; the second patient with the Prader-Willi syndrome was diagnosed with organic autism associated with mild mental retardation, impaired social adaptation in combination with stereotyped actions, impaired visual-spatial coordination, and cerebral palsy. In the first case, MRI showed posterior CC hypoplasia; in the second case, MRI showed hypoplasia of the CC isthmus.Conclusion. The level of cognitive deficit was to some extent a value associated with the thickness of the posterior CC. Apparently, a higher degree of myelination of nerve fibers contributes to a higher rate of transmission of nerve impulses along nerve fibers stimulating neurons. The results can be considered preliminary; a larger study is needed.

Streamline density and lesion volume reveal a postero-anterior gradient of corpus callosum damage in multiple sclerosis.

Although interhemispheric disconnection significantly contributes to disability in multiple sclerosis (MS), the topography, timeline and relationship of callosal damage accrual with hemispheric damage are still unclear. Streamline density and the presence of focal lesions in five callosal subregions were computed in 55 people with MS [13 relapsing-remitting (RRMS), 20 secondary progressive (SPMS), 22 primary progressive (PPMS)] and 24 healthy controls. Streamline density decrease was identified in SPMS in all corpus callosum (CC) subregions, in PPMS in the posterior CC and mid-posterior CC and in RRMS in the posterior CC. CC density was independently predicted by CC lesion volume and hemispheric lesion volume and independently predicted visuospatial memory, Expanded Disability Status Scale, manual dexterity and ambulation. The reduction in CC density across phenotypes suggests an earlier involvement of the posterior regions, followed only at a later stage by involvement of the anterior portions of the CC. Such interhemispheric disconnection seems to develop as a consequence of white matter macroscopic damage and exerts a relevant impact on motor and, to a lesser extent, cognitive disability.

Increased Notching of the Corpus Callosum in Fetal Alcohol Spectrum Disorder: A Callosal Misunderstanding?

In the medicolegal literature, notching of the corpus callosum has been reported to be associated with fetal alcohol spectrum disorders. Our purpose was to analyze the prevalence of notching of the corpus callosum in a fetal alcohol spectrum disorders group and a healthy population to determine whether notching occurs with increased frequency in the fetal alcohol spectrum disorders population. We performed a multicenter search for cases of fetal alcohol spectrum disorders and included all patients who had a sagittal T1-weighted brain MR imaging. Patients with concomitant intracranial pathology were excluded. The corpus callosum was examined for notches using previously published methods. A χ2 test was used to compare the fetal alcohol spectrum disorders and healthy groups. Thirty-three of 59 patients with fetal alcohol spectrum disorders (0-44 years of age) identified across all centers had corpus callosum notching. Of these, 8 had an anterior corpus callosum notch (prevalence, 13.6%), 23 had a posterior corpus callosum notch (prevalence, 39%), and 2 patients demonstrated undulated morphology (prevalence, 3.4%). In the healthy population, the anterior notch prevalence was 139/875 (15.8%), posterior notch prevalence was 378/875 (43.2%), and undulating prevalence was 37/875 (4.2%). There was no significant difference among the anterior (P = .635), posterior (P = .526), and undulating (P = .755) notch prevalence in the fetal alcohol spectrum disorders and healthy groups. There was no significant difference in notching of the corpus callosum between patients with fetal alcohol spectrum disorders and the healthy population. Although reported to be a marker of fetal alcohol spectrum disorders, notching of the corpus callosum should not be viewed as a specific finding associated with fetal alcohol spectrum disorders.

Neonatal white matter tract microstructure and 2-year language outcomes after preterm birth

AimTo determine whether variability in diffusion MRI (dMRI) white matter tract metrics, obtained in a cohort of preterm infants prior to neonatal hospital discharge, would be associated with language outcomes at age 2 years, after consideration of age at scan and number of major neonatal complications. Method30 children, gestational age 28.9 (2.4) weeks, underwent dMRI at mean post menstrual age 36.4 (1.4) weeks and language assessment with the Bayley Scales of Infant Development–III at mean age 22.2 (1.7) months chronological age. Mean fractional anisotropy (FA) and mean diffusivity (MD) were calculated for 5 white matter tracts. Hierarchical linear regression assessed associations between tract FA, moderating variables, and language outcomes. ResultsFA of the left inferior longitudinal fasciculus accounted for 17% (p = 0.03) of the variance in composite language and FA of the posterior corpus callosum accounted for 19% (p = 0.02) of the variance in composite language, beyond that accounted for by post-menstrual age at scan and neonatal medical complications. The number of neonatal medical complications moderated the relationship between language and posterior corpus callosum FA but did not moderate the association in the other tract. ConclusionLanguage at age 2 is associated with white matter metrics in early infancy in preterm children. The different pattern of associations by fiber group may relate to the stage of brain maturation and/or the nature and timing of medical complications related to preterm birth. Future studies should replicate these findings with a larger sample size to assure reliability of the findings.

Patterns of brain structural alteration in COPD with different levels of pulmonary function impairment and its association with cognitive deficits

BackgroundTo explore patterns of brain structural alteration in chronic obstructive pulmonary disease (COPD) patients with different levels of lung function impairment and the associations of those patterns with cognitive functional deficits using voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analyses based on high-resolution structural MRI and diffusion tensor imaging (DTI).MethodsA total of 115 right-handed participants (26 severe, 29 moderate, and 29 mild COPD patients and a comparison group of 31 individuals without COPD) completed tests of cognitive (Montreal Cognitive Assessment [MoCA]) and pulmonary function (forced expiratory volume in 1 s [FEV1]) and underwent MRI scanning. VBM and TBSS analyses were used to identify changes in grey matter density (GMD) and white matter (WM) integrity in COPD patients. In addition, correlation analyses between these imaging parameter changes and cognitive and pulmonary functional impairments were performed.ResultsThere was no significant difference in brain structure between the comparison groups and the mild COPD patients. Patients with moderate COPD had atrophy of the left middle frontal gyrus and right opercular part/triangular part of the inferior frontal gyrus, and WM changes were present mainly in the superior and posterior corona radiata, corpus callosum and cingulum. Patients with severe COPD exhibited the most extensive changes in GMD and WM. Some grey matter (GM) and WM changes were correlated with MoCA scores and FEV1.ConclusionsThese findings suggest that patients with COPD exhibit progressive structural impairments in both the GM and the WM, along with impaired levels of lung function, highlighting the importance of early clinical interventions.

Myelin Water Imaging and Transcranial Magnetic Stimulation Suggest Structure-Function Relationships in Multiple Sclerosis

Demyelination can be assessed structurally by magnetic resonance imaging and functionally with transcranial magnetic stimulation. Here we combined these techniques to investigate demyelination of the corpus callosum in multiple sclerosis. Our objective was to determine if corpus callosal demyelination impacts transcallosal inhibition (TCI). TCI is a brief suppression of voluntary activity in the primary motor cortex elicited by stimulation of the homologous region of the contralateral hemisphere, which is assumed to be transmitted via the corpus callosum. Magnetic resonance imaging and transcranial magnetic stimulation were performed in 26 participants with MS and 10 controls. Myelin water fraction (MWF) was measured in five regions of the corpus callosum and compared with the onset latency, duration, and depth of TCI as measured by electromyography at the forearm. Callosal MWF was greatest posteriorly compared to other regions of the corpus callosum. Lower MWF in MS compared to controls was more pronounced in the posterior corpus callosum. MS participants had a prolonged TCI duration (p=0.016), which correlated with EDSS (p=0.020) and disease duration (p=0.045). In MS, TCI depth correlated negatively with the MWF of the posterior callosal midbody (p=0.039), a region thought to mediate TCI transmission. In summary, TCI duration was increased in MS and demyelination of the posterior corpus callosum midbody was associated with measurable functional changes. This work demonstrates the potential for combining magnetic resonance imaging and transcranial magnetic stimulation with electromyography to draw insights about structure-function relationships in MS pathophysiology.

The effect of age of first exposure to competitive fighting on cognitive and other neuropsychiatric symptoms and brain volume

It has long been established that fighting sports such as boxing and mixed martial arts can lead to head injury. Prior work from this group on the Professional Fighters Brain Health Study found that exposure to repetitive head impacts is associated with lower brain volumes and decreased processing speed in fighters. Current and previously licensed professional fighters were recruited, divided into active and retired cohorts, and matched with a control group that had no prior experience in sports with likely head trauma. This study examined the relationship between age of first exposure (AFE) to fighting sports and brain structure (MRI regional volume), cognitive performance (CNS Vital Signs, iComet C3), and clinical neuropsychiatric symptoms (PHQ-9, Barratt Impulsiveness Scale). Brain MRI data showed significant correlations between earlier AFE and smaller bilateral hippocampal and posterior corpus callosum volumes for both retired and active fighters. Earlier AFE in active fighters was correlated with decreased processing speed and decreased psychomotor speed. Retired fighters showed a correlation between earlier AFE and higher measures of depression and impulsivity. Overall, the results help to inform clinicians, governing bodies, parents, and athletes of the risks associated with beginning to compete in fighting sports at a young age.

EP07.18: Frequency of the intrauterine diagnostic congenital Zika and Zika viruses detection in amniotic fluid: bi‐directional cohort study

To evaluate the frequency of diagnosis of Congenital Zika Syndrome (CZS) during pregnancy and the prevalence of confirmed cases through RT-PCR for ZIKV in amniotic fluid. A study with pregnant women with exanthema submitted to ultrasonography (prospective arm) and children with SZC (retrospective arm). Pregnant women with sonographic findings suggestive of SZC performed using Sansung WS80 Elite were submitted to amniocentesis for ZIKV research. Neurosonography (prospective arm) and Computed Tomography were performed in the neonate (retrospective arm). Chi-square test was used to compare the presence of symptoms between the prospective and the retrospective arm and the Mann-Whitney test to compare the number of ultrasonographies when intrauterine diagnosis was performed or not. 102 pairs of mothers and fetuses/children with CZS were included (28.7% prospective and 71.3% retrospective). Intrauterine diagnosis was performed in 52.9% of the total sample and in 100% of the prospective arm. The median sonographic examination was 3 vs 4 (had no intrauterine diagnosis vs the had intrauterine diagnosis, p < 0.001). Amniocentesis was performed in 19 pregnant women, with RT-PCR positive in 11 (57.9%). Among the ultrasound findings, ventriculomegaly was the main finding (43.1%), followed by microcephaly (42.2%), subcortical calcifications and/or nuclei of the base (30.4%), posterior fossa alterations (22.5%), arthrogryposis (7.8%) and corpus callosum dysgenesis (5.9%). Despite having a high frequency, microcephaly was not present in all CZS cases, and the diagnosis of the syndrome should take into account intracranial findings. The percentage of cases without intrauterine diagnosis was high. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Diffusion Imaging Biomarkers of Corpus Callosum Injury and Dose-Dependent Volumetric Changes Correlate with Attention and Processing Speed Changes after Brain Radiotherapy

Attention and processing speed are core cognitive functions subserved by the corpus callosum (CC), a critical white matter structure. We hypothesized that CC volume changes and diffusion weighted imaging (DWI) biomarkers of CC injury would correlate with changes in attention and processing speed function after brain radiotherapy (RT). We prospectively studied 29 patients with primary brain tumors who received fractionated RT. Patients underwent formal neuropsychological testing and high resolution volumetric MRI with DWI (b-values 0, 500, 1500 s/mm2 fit to single tensor) prior to and 6 months post RT. Auditory attention was measured with the Weschler Adult Intelligence Scale (WAIS-IV) Digit Span Forward test; processing speed was measured with the Delis-Kaplan Executive Function System Trail Making number sequencing (TM-NS) and letter sequencing (TM-LS) subtests. Reliable change indices accounting for practice effects (RCI-PE) were calculated to determine 0-6 month change on each measure. Image processing at each time point included auto-segmentation with volume calculations of regions of interest (ROIs): the entire CC and anterior, mid-anterior, central, mid-posterior, and posterior subdivisions. Tumor, tumor bed, edema, and segmentation errors were censored. DWI biomarkers including mean diffusivity (MD, increases with injury) and fractional anisotropy (FA, decreases with injury) were calculated. Mean dose to each ROI was determined. One sample t-tests (H0=0) were performed to determine significant group cognitive decline. Pearson correlation coefficients evaluated the relationship between RCI-PEs and clinical variables, dose, changes in volume, MD, and FA. Statistical significance was set at α=0.05. Processing speed (TM-LS) significantly declined 6-months post-RT (mean change -0.472, p = 0.003). Age and years of education did not influence attention or processing speed changes. Significant dose-dependent atrophy was seen in the mid-anterior (r = -0.432, p = 0.024), mid-posterior (r = -0.408, p = 0.031), and posterior CC (r = -0.600, p = 0.001). Smaller mid-anterior CC volume was associated with worse processing speed (TM-LS, r = 0.424, p = 0.031). Decreased FA in the anterior CC was associated with worse attention (digits forward, r = 0.401, p = 0.038) and decreased FA in the posterior CC was correlated with worse processing speed (TM-LS, r = 0.444, p = 0.02). Increased MD in the anterior CC (r = -0.386, p = 0.046) was correlated with worse attention (digits forward). In this prospective study, dose-dependent atrophy of CC subdivisions was seen after fractionated brain RT. Microstructural damage, including atrophy and white matter injury, within CC subdivisions was significantly associated with worse attention and processing speed. Damage to this critical structure is highly implicated in attention/processing speed changes after brain RT.

Glucose disturbances, cognitive deficits and white matter abnormalities in first-episode drug-naive schizophrenia.

Disturbance of glucose metabolism may be implicated in cognitive deficits of schizophrenia in its early phases. Many studies have reported the important role of widespread disruption of white matter (WM) connectivity in pathogenesis, cognitive deficit and psychopathology of schizophrenia. However, no study has investigated their inter-relationships in drug-naive first episode(DNFE) patients with schizophrenia. Glucose metabolism parameters including fasting glucose, insulin and homeostasis model of assessment-insulin resistance (HOMA-IR) index, cognitive performance on the MATRICS Consensus Cognitive Battery (MCCB) and the voxel-wised WM fractional anisotropy (FA) values were examined using DTI in 39 DNFE schizophrenia and 31 control subjects. The Positive and Negative Syndrome Scale was utilized for clinical symptoms. The patients showed significantly greater fasting plasma levels of glucose and insulin and HOMA-IR, and poorer cognitive scores, together with widespread reduced FA values in five brain areas, including left and right corpus callosum, superior longitudinal fasciculus, posterior thalamic radiation, and corona radiata (all p < 0.05). Association analysis showed that glucose level was positively associated with Digital Sequence Test and Continuous Performance Test, but negatively with FA values in posterior thalamic radiation and left corpus callosum in patients (all p < 0.05). Furthermore, multiple regression analysis revealed that the interactions of glucose × FA in left corpus callosum, longitudinal fasciculus and corona radiata were independent contributors to the Brief Visuospatial Memory Test (BVMT) of MCCB, while the interaction of glucose × FA in left corpus callosum, or in longitudinal fasciculus was associated with MCCB mazes and Trail Making A Test, respectively. Therefore, abnormal glucose metabolism, cognitive impairment and widespread disruption of WM structure occur in an early course of schizophrenia onset. An interaction between glucose metabolism abnormality and the WM dysconnectivity may lead to cognitive impairment.

Brain structure in children with congenital visual disorders and visual impairment.

AimTo examine if congenital visual impairment is associated with differences in brain anatomy in children.MethodTen children (8–12y) with congenital disorders of the peripheral visual system with severe visual impairment (SVI; >0.8 logMAR) or mild‐to‐moderate visual impairment (MVI; 0.6–0.8 logMAR) were compared to 21 typically sighted comparison (TSC) children. Thalamus volume, grey matter density, white matter microstructure, and integrity of visual tracts were investigated in SVI, MVI, and TSC groups with anatomical and diffusion‐weighted magnetic resonance imaging.ResultsCompared to the TSC group, the SVI group had lower white matter integrity in tracts of the visual system (optic radiations: SVI 0.35±0.015, TSC 0.39±0.007 [p=0.022]; posterior corpus callosum: SVI 0.37±0.019; TSC 0.42±0.009 [p=0.033]) and lower left thalamus volume (SVI 4.37±0.087; TSC 4.99±0.339 [p=0.015]). Neuroanatomical differences were greater in the SVI group, while no consistent differences between the MVI and TSC group were observed.InterpretationPosterior tracts of the visual system are compromised in children with congenital visual impairment versus those who are typically sighted. The severity of visual input appears to have affected neuroanatomical development as significant reductions were only found in the SVI group.What this paper adds Severe visual impairment in mid‐childhood is associated with reduced integrity of visual pathways and reduced thalamus volume.

Brain MRI features and scoring of leukodystrophy in adult-onset Krabbe disease.

To perform a systematic analysis and scoring of brain MRI white matter hyperintensities (WMH) in adult-onset Krabbe disease. We retrospectively collected basic clinical data and the first available brain MRI from patients with confirmed Krabbe disease with first clinical manifestations beyond 10 years of age. Data were obtained from our reference center for lysosomal diseases (n = 6) and from contacted authors of published articles describing patients with adult-onset Krabbe disease (n = 15). T2-weighted fluid-attenuated inversion recovery images of each patient were analyzed and scored using a radiologic score of WMH in a single center. The corticospinal tract was always affected by WMH (100% of patients), however, with some distinctions along the tract: the precentral gyrus (100%), corona radiata (95%), and posterior internal capsule (81%) were highly abnormal, whereas the mesencephalon (57%), pons (52%), and medulla oblongata (5%) were less affected. WMH were also frequently present in the posterior lateral periventricular white matter (95%), optic radiations (86%), postcentral gyrus (71%), medial lemniscus (62%), and corpus callosum, especially in the isthmus (71%), whereas the genu was always normal. A few patients did not have the classical MRI pattern but extensive hyperintensities (n = 3), or patchy distribution of hyperintensities mimicking an acquired etiology (n = 2), or very subtle hyperintensities of the corticospinal tract (n = 1). We specified the main locations of WMH, which were observed in the earliest stages of the disease and were also present in patients with atypical MRI pattern, highlighting the importance of radiologic features to guide the diagnosis.

Posterior Corpus Callosal Integrity based on Automated Fiber Quantification Predicts Age-related Decline of Cognitive Performance.

The posterior corpus callosum (PCC) has been involved in a variety of cognitive functions. However, the relationship between the microstructural features of PCC with cognitive performance remains unclear. Diffusion tensor imaging (DTI) provides a non-invasive neuroimaging technique to examine the microstructure of white matter fiber bundles through tractography. But the accuracy of fiber tracking is highly dependent on the selection of tractography algorithms. Automated fiber-tract quantification (AFQ) analysis provides a comprehensive characterization of intratract tissue along the length of white matter fiber bundles. In this study, we investigated the tract profiles in PCC using AFQ. Four tracts composing PCC were explored, i.e., posterior parietal (PP), superior parietal (SP), occipital (Occ) and temporal (Temp) tracts. We found that the average fractional anisotropy (FA) values in PP tract and SP tract were negatively correlated with subject age. Additionally, the average FA of PP tract was negatively associated with subject executive function score. Moreover, the FA of the second section of Occ tract was positively correlated with the subject language score. The results showed the age-related declines of subject white matter microstructural integrity and cognitive performance. The correlations of tract FA values and cognitive scores shed light on the contributions of PCC microstructural characteristics to normal cognitive function.

Altered structural connectivity associated with motor improvement in chronic supratentorial ischemic stroke.

This study aimed to identify brain structural changes associated with motor recovery, after neurorehabilitation in patients with chronic supratentorial ischemic stroke. Twenty-one chronic stroke patients with an improved Fugl-Meyer motor assessment score were retrospectively included in the study. All participants underwent diffusion tensor imaging twice: before and after the outpatient neurorehabilitation program. A fractional anisotropy map, derived from diffusion tensor imaging, was used to identify changes in brain structural connectivity. A paired t-test of the fractional anisotropy maps was performed to calculate statistical significance. Structural connectivity was significantly increased along the corticospinal tract pathway in the ipsilesional hemisphere (uncorrected P<0.005 with cluster size>10 voxels). The posterior corpus callosum, which connects the bilateral hemispheres, and the bilateral middle cerebellar peduncle, which is the main pathway of the afferent fibers from the cerebrum to cerebellum, also showed significantly increased structural connectivity (uncorrected P<0.005 with cluster size>10 voxels). Motor-associated brain regions, mainly in the ipsilesional hemisphere, were involved in motor improvements in patients with chronic supratentorial ischemic stroke. These findings could be incorporated into the neurorehabilitation of chronic stroke patients for improved motor recovery.

Abnormal Embryonic Development of Cerebral Arteries as a Potential Cause of Moyamoya Disease

Moyamoya disease (MMD) is a cerebrovascular disorder, currently defined as progressive stenosis of intracranial internal carotid artery and its main branches with secondary formation of netlike vessels. Its precise formation mechanism, however, is unknown. We propose that MMD is caused by abnormal embryonic development of the cerebral arteries and also propose a mechanism for MMD formation. The anterior, middle, and posterior cerebral arteries, anterior choroidal arteries (AChoA) and posterior choroidal arteries, and posterior corpus callosum arteries were analyzed separately for each patient with MMD to determine whether the arteries exhibited the following characteristics, which we regarded as remnants of primitive vessels: 1) plexiform arteries rather than normal artery trunks; 2) clustered arteries converging at locations of normal artery trunks; and 3) dilated AChoA. We retrospectively analyzed 39 consecutive patients with MMD, of whom 30 had anterior cerebral arteries, 31 middle cerebral arteries, 10 posterior cerebral arteries, 30 AChoAs, 18 posterior choroidal arteries, and 20 posterior corpus callosum arteries and had the characteristics of primitive vessel remnants. Altogether, 82.05% of the patients had the remnants of primitive vessels. MMD is more likely to be caused by abnormalities of cerebral artery development, which mainly occur in the embryonic period or postnatally. The abnormality developing processes include sprouting angiogenesis, vessel fusion, and pruning, which primarily affect cranial ramus of primitive internal carotid artery, may occasionally affect the caudal ramus of the primitive internal carotid artery, and rarely affect the vertebrobasilar artery system. So-called moyamoya vessels comprise unfused primitive small vessels; to compensate, enlarged AChoAs remain undegenerated but are not dilated.