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Nature Reviews. Neuroscience Apr 2007Agenesis of the corpus callosum (AgCC), a failure to develop the large bundle of fibres that connect the cerebral hemispheres, occurs in 1:4000 individuals. Genetics,... (Review)
Review
Agenesis of the corpus callosum (AgCC), a failure to develop the large bundle of fibres that connect the cerebral hemispheres, occurs in 1:4000 individuals. Genetics, animal models and detailed structural neuroimaging are now providing insights into the developmental and molecular bases of AgCC. Studies using neuropsychological, electroencephalogram and functional MRI approaches are examining the resulting impairments in emotional and social functioning, and have begun to explore the functional neuroanatomy underlying impaired higher-order cognition. The study of AgCC could provide insight into the integrated cerebral functioning of healthy brains, and may offer a model for understanding certain psychiatric illnesses, such as schizophrenia and autism.
Topics: Child Behavior; Child, Preschool; Corpus Callosum; Developmental Disabilities; Female; Humans; Infant; Infant, Newborn; Mental Disorders; Neuropsychological Tests; Pregnancy
PubMed: 17375041
DOI: 10.1038/nrn2107 -
Seizure Apr 2016Corpus callosum (CC) is the largest forebrain commissure. This review focuses on the significance of CC for seizure disorders, the role of CC in seizure spread and the... (Review)
Review
PURPOSE
Corpus callosum (CC) is the largest forebrain commissure. This review focuses on the significance of CC for seizure disorders, the role of CC in seizure spread and the surgical disruption of callosal fibers (callosotomy) for treatment of patients with drug-resistant epilepsy.
METHODS
Personal experience/extensive literature review.
RESULTS
Structural CC pathologies comprise developmental abnormalities, callosal involvement in identified disorders, transient imaging findings and microstructural changes. Epilepsies are reported in up to two thirds of patients with complete or partial CC agenesis (AgCC). However, AgCC per se is not indicative for seizure disorders. Moreover, additional malformations of cortical development (MCD) are causal. Microstructural CC abnormalities are detected by advanced imaging techniques, are part of diffuse white matter disturbances and are related to cognitive deficits. The etiological significance remains unexplained. However, they are also found in non-epileptic benign and transient disorders. In drug-resistant epilepsies with violent drops to the floor ("drop seizures") callosotomy may be beneficial in seizure reduction. Since the EEG after callosotomy exhibits a single seizure focus in up to 50% of patients, consecutive resective surgical methods might be successful.
CONCLUSION
CC is part of cerebral white matter and anomalies cannot act per se as seizure onset zone. Imaging techniques demonstrate additional lesions in patients with epilepsies. CC is the major pathway for seizure generalization. Therefore, callosotomy is used to prevent generalized drop seizures.
Topics: Agenesis of Corpus Callosum; Corpus Callosum; Electroencephalography; Epilepsy; Humans; Seizures; Treatment Outcome
PubMed: 27010176
DOI: 10.1016/j.seizure.2016.02.012 -
Brain Structure & Function Mar 2022Following a series of seminal studies in the 1980s, left or mixed hand preference is widely thought to be associated with a larger corpus callosum than right handedness,... (Meta-Analysis)
Meta-Analysis Review
Following a series of seminal studies in the 1980s, left or mixed hand preference is widely thought to be associated with a larger corpus callosum than right handedness, influencing the interpretation of findings and various theories related to interhemispheric processing, brain lateralisation, and hand preference. Recent reviews, however, find inconsistencies in the literature and cast doubt on the existence of such an association. The present study was conducted to clarify the relationship between hand preference and callosal morphology in a series of meta-analyses. For this purpose, articles were identified via a search in PubMed and Web Of Science databases. Studies reporting findings relating to handedness (assessed as hand preference) and corpus-callosum morphology in healthy participants were considered eligible. On the basis of a total of k = 24 identified studies and databases, random-effects meta-analyses were conducted considering four different group comparisons: (a) dominantly right- (dRH) and left-hand preference (dLH), (b) consistent right (cRH) and non-cRH preference, (c) cRH with mixed-hand preference (MH), and (d) cRH with consistent left-hand hand preference (cLH). For none of these meta-analyses did we find a significant effect of hand preference, and narrow confidence intervals suggest that the existence of population effects larger than 1% explained variance could be excluded. For example, considering the comparison of dRH and dLH (k = 14 studies; 1910 dRH and 646 dLH participants) the mean effect size was Hedge's g = 0.016 (95% confidence interval: - 0.12 to 0.15; explained variance: < 0.001%). Thus, the common practice of assuming an increase in callosal connectivity based on mixed or left hand preference is likely invalid.
Topics: Brain; Corpus Callosum; Functional Laterality; Hand; Healthy Volunteers; Humans
PubMed: 34851460
DOI: 10.1007/s00429-021-02431-4 -
Annals of Clinical and Translational... Jan 2023Neonatal imaging studies report corpus callosum abnormalities after neonatal hypoxic-ischaemic encephalopathy (HIE), but corpus callosum development and relation to...
OBJECTIVE
Neonatal imaging studies report corpus callosum abnormalities after neonatal hypoxic-ischaemic encephalopathy (HIE), but corpus callosum development and relation to cognition in childhood are unknown. Using magnetic resonance imaging (MRI), we examined the relationship between corpus callosum size, microstructure and cognitive and motor outcomes at early school-age children cooled for HIE (cases) without cerebral palsy compared to healthy, matched controls. A secondary aim was to examine the impact of HIE-related neonatal brain injury on corpus callosum size, microstructure and growth.
METHODS
Participants aged 6-8 years underwent MRI, the Movement Assessment Battery for Children Second Edition and Wechsler Intelligence Scale for Children Fourth Edition. Cross-sectional area, volume, fractional anisotropy and radial diffusivity of the corpus callosum and five subdivisions were measured. Multivariable regression was used to assess associations between total motor score, full-scale IQ (FSIQ) and imaging metrics.
RESULTS
Adjusting for age, sex and intracranial volume, cases (N = 40) compared to controls (N = 39) demonstrated reduced whole corpus callosum area (β = -26.9, 95% confidence interval [CI] = -53.17, -0.58), volume (β = -138.5, 95% CI = -267.54, -9.56), fractional anisotropy and increased radial diffusivity (P < 0.05) within segments II-V. In cases, segment V area (β = 0.18, 95% CI = 0.004, 0.35), volume (β = 0.04, 95% CI = 0.001, 0.079), whole corpus callosum fractional anisotropy (β = 13.8 95% CI = 0.6, 27.1) and radial diffusivity (β = -11.3, 95% CI = -22.22, -0.42) were associated with FSIQ. Growth of the corpus callosum was restricted in cases with a FSIQ ≤85, and volume was reduced in cases with mild neonatal multifocal injury compared to white matter injury alone.
INTERPRETATION
Following neonatal HIE, morphological and microstructural changes in the corpus callosum are associated with reduced cognitive function at early school age.
Topics: Child; Humans; Infant, Newborn; Brain Injuries; Cognition; Corpus Callosum; Diffusion Magnetic Resonance Imaging; Magnetic Resonance Imaging; Case-Control Studies
PubMed: 36480557
DOI: 10.1002/acn3.51696 -
Infectious Diseases Now Feb 2021
Topics: Brain Diseases; Brain Edema; COVID-19; Cerebrovascular Circulation; Corpus Callosum; Humans; Male; Middle Aged; SARS-CoV-2; Treatment Outcome
PubMed: 33027622
DOI: 10.1016/j.medmal.2020.09.018 -
Neurologia I Neurochirurgia Polska 2023Corpus callosum abnormalities are complex, aetiologically diverse, and clinically heterogeneous conditions. Counselling parents regarding their causes and associated...
INTRODUCTION
Corpus callosum abnormalities are complex, aetiologically diverse, and clinically heterogeneous conditions. Counselling parents regarding their causes and associated syndromes, and predicting the neurodevelopmental and seizure risk prognosis, is challenging.
MATERIAL AND METHODS
We describe the clinical characteristics, associated anomalies, and neurodevelopmental outcomes of children with agenesis of corpus callosum (ACC). Fifty-one neonates with ACC/hypoplasia of the corpus callosum were identified over a 17-year period, and their medical records were retrospectively reviewed.
RESULTS
Patients were classified into two groups depending on the presence or absence of associated abnormalities. The first group (17 patients, 33.4%) presented with isolated callosal anomalies. The second group included 34 patients (66.6%) with associated cerebral and extracerebral anomalies. We achieved an identifiable genetic aetiology in 23.5% of our cohort. Magnetic resonance imaging was performed in 28 patients (55%), and of these 39.3% had additional brain anomalies. During the study period, five patients died early in the neonatal period and four were lost to follow up. Of the 42 followed patients, 13 (31%) showed normal neurodevelopment, 13 (31%) showed mild delay, and 16 (38%) had a severe delay. Fifteen (35.7%) had epilepsy.
CONCLUSIONS AND CLINICAL IMPLICATIONS
We have confirmed that callosal defects are frequently accompanied by brain and somatic anomalies. Additional abnormalities were shown to be significantly associated with developmental delay and increased risk of epilepsy. We have highlighted essential clinical features that may provide diagnostic clues to physicians and we have given examples of underlying genetic disorders. We have provided recommendations about extended neuroimaging diagnostics and widespread genetic testing that may impact upon daily clinical practice. Paediatric neurologists may therefore use our findings to help base their decisions regarding this matter.
Topics: Infant, Newborn; Humans; Child; Corpus Callosum; Retrospective Studies; Agenesis of Corpus Callosum; Brain; Brain Diseases; Magnetic Resonance Imaging
PubMed: 37078131
DOI: 10.5603/PJNNS.a2023.0026 -
European Review For Medical and... Jan 2022Corpus callosum (CC) is commonly affected in multiple sclerosis (MS), with known association between CC atrophy and MS clinical activity. In this study, we assessed the...
OBJECTIVE
Corpus callosum (CC) is commonly affected in multiple sclerosis (MS), with known association between CC atrophy and MS clinical activity. In this study, we assessed the association of callosal atrophy, lesions volume and residual CC volume with the clinical disability of early MS patients.
SUBJECTS AND METHODS
Thirteen MS subjects (9 female, mean age 36.9 years), studied with magnetic resonance imaging (MRI) were selected. MRI scans were performed at baseline (T0), at 6 (T1), 12 (T2), and 24 months (T3) from baseline. CC was segmented into three sections (genu, body, and splenium); callosal boundaries were outlined and all CC lesions were manually traced. Normal CC and CC lesion volumes were measured using a semiautomatic software.
RESULTS
From January 2014 to December 2016, all selected patients had confluent lesions on MRI at T3 with a significant increase in the size of confluent lesions compared to baseline (p=0.0007). At T1, a significant increase in the size of confluent (p=0.02) and single lesions located in the callosal body (p=0.04) was detected in patients with EDSS ≥1.5. Also, CC residual volume (CCR) rather than the whole CC volume (CCV) significantly correlated (p=0.03) with the clinical progression of MS in the whole cohort.
CONCLUSIONS
In early MS patients with higher EDSS at baseline, a significant increase in confluent CC lesions size is evident, particularly in the callosal body. Also, median CCR is significantly associated with MS progression in the whole MS group, regardless of initial EDSS. Given their significant association with disability, we encourage measuring CC body lesions and residual CC size for therapeutic decisions and prognostic planning in early MS.
Topics: Adult; Atrophy; Corpus Callosum; Disease Progression; Female; Humans; Magnetic Resonance Imaging; Multiple Sclerosis
PubMed: 35048999
DOI: 10.26355/eurrev_202201_27772 -
Danish Medical Journal Oct 2013The overarching objective of the thesis was to investigate the morphological changes in the corpus callosum (CC) in aging and dementia in relation to its role in... (Review)
Review
The overarching objective of the thesis was to investigate the morphological changes in the corpus callosum (CC) in aging and dementia in relation to its role in cognitive and motor decline. The CC is the largest white matter tract in the brain, containing upwards of 200 million axons, and is believed important for communication and interaction between the two cerebral hemispheres. Historically, the role of white matter, including the CC, in relation to cognitive function has often been eclipsed by the predominance of the cortex, and led to a "corticocentric" view of the brain and cognitive function. However, from the 1960s and onwards, the role of lesions in the white matter in the appearence of cognitive deficits and diseases such as dementia has become increasingly evident. Many studies have indicated that AD is associated with CC atrophy, but the precise pattern of subregional CC atrophy in different disease stages remains undetermined. In study I, we establish that atrophy is present primarily in the posterior CC early in AD, and that atrophy of the CC is associated with faster disease progression. This finding supports a model where posterior atrophy is the earliest changes in the CC in AD patients, with atrophy of anterior CC being a later pathological event. To further elucidate the role of CC atrophy in dementia, we examined a population of 329 elderly subjects, and found that a higher rate of tissue loss in posterior CC is associated with an increased risk of dementia. This study represents the first to examine CC in elderly subjects longitudinally. In the same cohort, we investigated whether impairment in specific cognitive domains was associated with CC tissue loss. Previous studies had shown that processing speed and executive functions may be particularly reliant on the CC. Our findings indicated that CC tissue loss leads to selective impairment of processing speed but not memory or executive function deficits. Finally, CC tissue loss was also associated with impairment of motor function. Overall, the present findings confirm and extend the role of the CC in dementia and age-associated cognitive and motor deficits.
Topics: Aging; Animals; Atrophy; Brain Diseases; Cognition Disorders; Corpus Callosum; Dementia; Disease Progression; Female; Humans; Male
PubMed: 24083533
DOI: No ID Found -
Neuroradiology May 2020The splenium of the corpus callosum is the most posterior part of the corpus callosum. Its embryological development, anatomy, vascularization, function, imaging of... (Review)
Review
BACKGROUND AND PURPOSE
The splenium of the corpus callosum is the most posterior part of the corpus callosum. Its embryological development, anatomy, vascularization, function, imaging of pathology, possible pathophysiological mechanisms by which pathology may develop and the clinical consequences are discussed.
METHODS
A literature-based description is provided on development, anatomy and function. MR and CT images are used to demonstrate pathology. The majority of pathology, known to affect the splenium, and the clinical effects are described in three subsections: (A) limited to the splenium, with elaboration on pathophysiology of reversible splenial lesions, (B) pathology in the cerebral white matter extending into or deriving from the splenium, with special emphasis on tumors, and (C) splenial involvement in generalized conditions affecting the entire brain, with a hypothesis for pathophysiological mechanisms for the different diseases.
RESULTS
The development of the splenium is preceded by the formation of the hippocampal commissure. It is bordered by the falx and the tentorium and is perfused by the anterior and posterior circulation. It contains different caliber axonal fibers and the most compact area of callosal glial cells. These findings may explain the affinity of specific forms of pathology for this region. The fibers interconnect the temporal and occipital regions of both hemispheres reciprocally and are important in language, visuospatial information transfer and behavior. Acquired pathology may lead to changes in consciousness.
CONCLUSION
The development, location, fiber composition and vascularization of the splenium make it vulnerable to specific pathological processes. It appears to play an important role in consciousness.
Topics: Agenesis of Corpus Callosum; Corpus Callosum; Humans; Magnetic Resonance Imaging; Tomography, X-Ray Computed
PubMed: 32062761
DOI: 10.1007/s00234-019-02357-z -
Brain Structure & Function Dec 2022Axonal damage in the corpus callosum is prevalent in multiple sclerosis (MS). Although callosal damage is associated with disrupted functional connectivity between...
Axonal damage in the corpus callosum is prevalent in multiple sclerosis (MS). Although callosal damage is associated with disrupted functional connectivity between hemispheres, it is unclear how this relates to cognitive and physical disability. We investigated this phenomenon using advanced measures of microstructural integrity in the corpus callosum and surface-based homologous inter-hemispheric connectivity (sHIC) in the cortex. We found that sHIC was significantly decreased in primary motor, somatosensory, visual, and temporal cortical areas in a group of 36 participants with MS (29 relapsing-remitting, 4 secondary progressive MS, and 3 primary-progressive MS) compared with 42 healthy controls (cluster level, p < 0.05). In participants with MS, global sHIC correlated with fractional anisotropy and restricted volume fraction in the posterior segment of the corpus callosum (r = 0.426, p = 0.013; r = 0.399, p = 0.020, respectively). Lower sHIC, particularly in somatomotor and posterior cortical areas, was associated with cognitive impairment and higher disability scores on the Expanded Disability Status Scale (EDSS). We demonstrated that higher levels of sHIC attenuated the effects of posterior callosal damage on physical disability and cognitive dysfunction, as measured by the EDSS and Brief Visuospatial Memory Test-Revised (interaction effect, p < 0.05). We also observed a positive association between global sHIC and years of education (r = 0.402, p = 0.018), supporting the phenomenon of "brain reserve" in MS. Our data suggest that preserved sHIC helps prevent cognitive and physical decline in MS.
Topics: Humans; Corpus Callosum; Multiple Sclerosis; Disability Evaluation; Multiple Sclerosis, Relapsing-Remitting; Cognitive Dysfunction; Magnetic Resonance Imaging
PubMed: 35536387
DOI: 10.1007/s00429-022-02498-7