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PubMed1997

Corpus callosum: neuropathology.

The anatomical and histological structure of Corpus callosum is analysed, mainly in relation with cell composition and fibre distribution. The vascularization of Corpus callosum is analyzed in relation with the distribution of the supplying arteries and the fine organization of small vessels. The first part of the presentation deals with damages of corpus callosum as a consequence of hemorrhagic and ischemic vasculopathies. The lesions may be direct or indirect; the latter follow the distruction of hemispheric areas interconnecting through the corpus callosum or occur as the product of reduced flow in the territories of carotid and vertebral arteries. A special mention is dedicated to the anatomoclinical syndromes developing after damages to the anterior or posterior section of Corpus callosum. The second part deals with specific diseases such as Marchiafava-Bignami's disease, which is treated as an example of glial cell pathology and chronic edema. The third part deals with tumors. Besides lymphomas which need a separate consideration for their modality of growth, neuroepithelial tumors are discussed. The most important problem is that of invasion through the Corpus callosum. The cell traffic in this structure with all the connected questions about cell migration, adhesiveness and motility are presented. Pathology of Corpus callosum is extended also to anatomically related median structures such as fornix and septum pellucidum. The latter is one of the principal pathways of diffusion in gliomas.

Corpus Callosum↗

PubMed1984

The normal, absent, and abnormal corpus callosum: sonographic findings.

The normal corpus callosum can be identified on sonography as a hypoechoic band superior to the third ventricle on the midline sagittal scan and forming the roof of the lateral ventricles on the coronal scan. Absence of the corpus callosum may be partial or complete and may be developmental or acquired. The sonographic features and associated intracranial abnormalities in six patients are presented. The findings include separation of the lateral ventricles with increased angulation and concavity to the medial border due to the prominent bundles of Probst, and dilatation and elevation of the third ventricle with interposition between the lateral ventricles.

Agenesis of Corpus Callosum↗

PubMed1996

Prenatal diagnosis of intracranial lipoma associated with agenesis of the corpus callosum.

BACKGROUND: Lipoma of the corpus callosum is a congenital malformation present in 1:1700 individuals. Only three cases of prenatal sonographic diagnosis have been described. CASES: Two cases of prenatal sonographic diagnosis of intracranial lipoma are described. The first case was visible at 26 weeks' gestation and was associated with partial agenesis of the corpus callosum, a characteristic midline gyral pattern, and fetal colpocephaly. The second case was an isolated lipoma diagnosed at 37 weeks. In both cases transvaginal scanning and color Doppler studies were useful adjuncts in making the diagnosis. CONCLUSION: Prenatal sonographic diagnosis of intracranial lipoma associated with agenesis of the corpus callosum is possible as early as 26 weeks' gestation. Because prognosis depends on associated anomalies, a detailed examination of fetal intracranial anatomy and a complete anatomic survey should be performed. Awareness of this lesion can be expected to increase its detection on prenatal sonography.

Adult↗

PubMed1990

Spatial frequency thresholds of single striate cortical cells in neonatal corpus callosum sectioned cats.

Following section of the corpus callosum at 1-6 postnatal weeks in cats, behavioral visual acuity was measured binocularly and monocularly from 6-29 postnatal weeks; physiological determination of spatial frequency thresholds of single striate cortical cells was performed when the cats were at least 8 months old. Results were compared between cats with callosum section at each postnatal week, as well as with normal cats. Cats with callosotomy at 1-3 postnatal weeks had deficits in behavioral visual acuity, and the deficits were greatest in the youngest operated cats. Cats with callosotomy at 1-2 postnatal weeks failed to resolve as high spatial frequencies as did normal cats, and the resolution of the 1 week operated cats was lower than the resolution of the 2 week operated cats. Cats with callosotomy at 3-6 postnatal weeks had spatial frequency thresholds that were equivalent to those of normal cats. To determine what kinds of striate cells had reduced spatial resolution following neonatal corpus callosum section, cells were categorized according to class (Simple, Complex), receptive field location (Central, Peripheral), and monocular behavioral acuity eye performance (Better Eye, Worse Eye). Cats with corpus callosum section during postnatal week 1 had the lowest spatial resolution for all cell categories compared to all groups tested. However, cats with callosum section during postnatal week 2 had normal spatial frequency thresholds for Simple, Central and Better Eye categories. The cats with callosum section in postnatal weeks 3-6 had normal spatial frequency thresholds for all cell categories. For corpus callosum sectioned cats with and without visual deficits, and for normal cats, visual acuity measured behaviorally is significantly related to visual acuity measured physiologically. The results show that neonatal corpus callosum section in cats can affect behavioral visual acuity, as well as the spatial frequency thresholds of many categories of striate cortical cells. However, callosum section at different ages affects different populations of cortical cells. Furthermore, the results suggest that neonatal corpus callosum section may directly affect a single fundamental property of cells in primary visual cortex with a resulting disruption of many visual functions.

Aging↗

PubMed1997

Quantitative magnetic resonance imaging of the corpus callosum in childhood onset schizophrenia.

Corpus callosum size has been found to be abnormal in adult schizophrenia, and other studies have implicated abnormal interhemispheric communication in this disorder. To assess continuity with brain abnormalities in the later onset disorder and to further localize brain maldevelopment, this structure was examined in a unique sample of childhood onset schizophrenics. Anatomic brain magnetic resonance imaging scans were acquired for 25 patients (mean age 13.9 +/- 2.1) who had onset of schizophrenia by age 12 (mean age at onset 9.9 +/- 1.9) and 55 normal children. The midsagittal area of the corpus callosum was divided into seven sections. With no adjustment for brain volume, no diagnostic differences were observed. After adjustment for the smaller cerebral volume of the schizophrenics, larger total, anterior and posterior corpus callosum areas emerged for the schizophrenics. These findings provide further evidence for continuity between childhood onset and later onset schizophrenia and support other studies showing white matter sparing in the context of decreased cortical volume.

Adolescent↗

PubMed1984

Binocularity in the visual cortex of the adult cat does not depend on the integrity of the corpus callosum.

The importance of the corpus callosum for binocular interaction in areas 17 and 18 of the adult cat is still a matter of controversy, since its specific role in integrating information from the two eyes has been suggested by some and questioned by others. We have reanalyzed the problem by assessing binocular interaction for single neurons in areas 17 and 18 of adult cats submitted to section of the posterior two-thirds of the corpus callosum. In 5 cats this interhemispheric disconnection was performed from 10 days to 7 weeks before the electrophysiological recordings; in another cat callosal afferents to the recording sites were at first partially eliminated by an acute lesion of corresponding cortical zones in the other hemisphere, and thereafter completely interrupted by a posterior callosal section performed in the same recording session. Recordings were mainly aimed at the callosal zone of areas 17 and 18, which coincides with the border between these two areas and corresponds to visual field regions bordering the vertical meridian. Electrophysiological recordings were carried out in awake, unanesthetized animals in which all nociceptive pathways were previously interrupted by a midpontine pretrigeminal transection. The results indicate that the interhemispheric disconnection, whether acute or chronic, does not disrupt binocularity in areas 17 and 18; moreover, the analysis of the ocular dominance for binocular neurons did not reveal any imbalance between the inputs from the two eyes, since at all levels of eccentricity the majority of binocular neurons was equally activated by both eyes. Since in previous experiments on anesthetized cats, section of the corpus callosum apparently reduced binocular interaction in areas 17 and 18, we suggest that such an effect, which was lacking in our unanesthetized cats, was probably due to an interaction or summation between callosotomy and anesthesia.

Animals↗

PubMed2004

Levodopa-responsive parkinsonism in hereditary spastic paraplegia with thin corpus callosum.

Hereditary spastic paraplegia with thin corpus callosum is a rare degenerative disease, which is characterized by a progressive weakness of the lower limbs with a hypoplastic corpus callosum, and is often associated with other symptoms such as mental impairment, amyotrophy, sensory disturbances, dysuria, nystagmus and cataract. We describe two siblings (brother and sister) who showed a thin corpus callosum on MRI, one of whom showed the pure form of progressive spastic paraplegia, while the other showed predominant levodopa-responsive parkinsonism. The present cases are illustrative of a phenotypic heterogeneity in the same family of spastic paraplegia with a thin corpus callosum, despite the identical neuroimaging findings, and also presented another form of autosomal recessive juvenile levodopa-responsive parkinsonism.

Adolescent↗

PubMed2005

Agenesis of the corpus callosum: lessons from humans and mice.

BACKGROUND AND PURPOSE: The corpus callosum serves as a bridge to associate fibres between the two cerebral hemispheres. In placental mammals, this commissure provides for higher order neurological advantages. The molecular pathways involved in the development and pathogenesis of accallosal defects are sparse. The article reviews the current progress of studies undertaken to discern the embryological and genetic basis of the development of the corpus callosum. SOURCES OF DATA: The literature, including from sources such as MEDLINE and OMIM, were subjected to searches for articles reporting findings on corpus callosum development in humans and mice. PRINCIPAL FINDINGS: At least forty-six malformation syndromes and metabolic disorders have been reported in patients with complete agenesis or hypoplasia (dysgenesis) of the corpus callosum. Thirteen of these syndromes have an unknown mode of genetic inheritance, and the remaining syndromes and metabolic disorders exhibit either autosomal or X-linked inheritance among affected families. The use of patients with accallosal defects have identified mutations in at least thirty genes of the human genome, and therefore with roles implicated in the development of the corpus callosum. Patients with chromosome aberrations have been useful in defining regions on chromosomes that contain candidate genes for the development of the corpus callosum. At least eighteen different human chromosomes with numerical and/or structural aberrations have been reported in patients with acallosal defects. The mouse is an excellent model to study the structural and genetic factors that influence the development of the corpus callosum, with many similarities evident in humans. Spontaneous development of acallosal defects has been reported in at least seventeen mouse strains. Furthermore, with the use of Genetically Engineered Mice, a minimum of 15 candidate callosal agenesis genes were modeled in order to provide insightful knowledge of the molecular-structural parameters required for development of the corpus callosum. Of these mice, six had complete true agenesis of the corpus callosum, five had either true agenesis or hypoplasia of the corpus callosum, and four had hypoplasia of the corpus callosum. CONCLUSIONS: The molecular mechanisms implicated in the pathogenesis of agenesis or hypoplasia of the corpus callosum are at the verge of discovery, and are challenged by the complexity of many genes involved. Despite these barriers, findings from a complementary human-mouse model system have been helpful in understanding the genetic (molecular) causes of accallosal defects, a fascinating phenotype for over a century.

Animals↗

PubMed1989

[Arterial vascularization of the corpus callosum in man].

The blood supply of the corpus callosum in Man is studied in 20 brains by injecting the vascular system with gelatinous indian ink. The arterial vascularization of the corpus callosum is derived, although in an unequal way, from both of the arterial systems of the brain: the carotid system and the vertebral-basilar system. The carotid system contributes mainly to this supply by the anterior cerebral artery which is the main artery of the corpus callosum. It accessorily contributes to it by the anterior communicating artery which gives off an inconstant artery called median artery of the corpus callosum. The vertebral-basilar system contributes to the blood supply of the corpus callosum by the terminal branches and by choroidal branches of the posterior cerebral artery. These various arteries give off perforating arteries which are direct or indirect, short, of middle length or long. Inside the corpus callosum, these various arteries give off numerous terminal and collateral branches which run between the nervous fibers. They anastomose with homologous neighbouring branches to form a characteristic vascular network. The arrangement of this network is in close connection with the disposition and the orientation of the commisural fibers which form the different parts of the corpus callosum.

Adult↗

PubMed2002

Progression of corpus callosum atrophy in Alzheimer disease.

BACKGROUND: Atrophy of the corpus callosum in the absence of primary white matter degeneration reflects loss of intracortical projecting neocortical pyramidal neurons in Alzheimer disease (AD). OBJECTIVES: To determine individual rates of atrophy progression of the corpus callosum in patients with AD and to correlate rates of atrophy progression with clinical disease severity and subcortical disease. METHODS: Magnetic resonance imaging-derived measurements of corpus callosum size were studied longitudinally in 21 patients clinically diagnosed as having AD (mean observation time, 17.0 +/- 8.5 months) and 10 age- and sex-matched healthy controls (mean observation time, 24.1 +/- 6.8 months). RESULTS: Corpus callosum size was significantly reduced in AD patients at baseline. Annual rates of atrophy of total corpus callosum, splenium, and rostrum were significantly larger in AD patients (-7.7%, -12.1%, and -7.3%, respectively) than in controls (-0.9%, -1.5%, and 0.6%, respectively). Rates of atrophy of the corpus callosum splenium were correlated with progression of dementia severity in AD patients (rho = 0.52, P<.02). The load of subcortical lesions at baseline (P<.05) predicted rate of anterior corpus callosum atrophy in healthy controls. Rates of atrophy of corpus callosum areas were independent of white matter hyperintensity load in patients with AD. CONCLUSIONS: Measurement of corpus callosum size allows in vivo mapping of neocortical neurodegeneration in AD over a wide range of clinical dementia severities and may be used as a surrogate marker for evaluation of drug efficacy.

Aged↗

PubMed1990

Bilateral receptive fields in cortical area SII: contribution of the corpus callosum and other interhemispheric commissures.

The corpus callosum contributes to the interhemispheric transfer of somatosensory information. Since the somatosensory pathways are essentially crossed, a number of studies have postulated that the corpus callosum may be responsible for the presence of bilateral receptive fields (RFs) in cortical area SII. Moreover, subcortical structures, as well as some of the other commissures, may also contribute to the bilateral nature of these cells. In order to assess the relative importance of the corpus callosum, this study compared the RF properties of cells in area SII of callosum-sectioned cats to normal cats, using single-cell recordings. Results showed that the corpus callosum makes an important contribution to the bilateral activation of cells in SII, since the proportion of cells with bilateral RFs found in callosum-sectioned cats was less than half that obtained in normal cats. The decrease in the proportion of bilateral RFs was found for all body regions with the exception of the face. However, the substantial number of bilateral RFs remaining in callosotomized cats indicates that this structure is not the sole contributor to the bilateral activation of cells in SII. In order to determine whether this residual bilateral activation might be mediated by the other interhemispheric commissures, a group of cats was subjected, besides the callosotomy, to the additional transection of their subcortical commissures, including the anterior, posterior, habenular, and intertectal commissures, as well as the massa intermedia. When this group of deep-split cats was compared to the callosotomized group, the results indicated that the contribution of the other commissures to bilateral activation is negligible, since approximately the same proportion of bilateral RFs was encountered in the two groups. The relative importance of the callosal contribution to bilateral RFs of different body regions is discussed with respect to the roles commonly attributed to this structure.

Animals↗

PubMed2006

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.

Atrophy↗

PubMed1987

Coherence patterns of the infant sleep EEG in absence of the corpus callosum.

The role of the corpus callosum in the relationship between the EEGs of the two cerebral hemispheres was studied by comparing 3 infants with congenital agenesis of the corpus callosum with a group of neurologically normal infants. Coherence functions were computed for symmetrical pairs of EEG derivations; in the frequency bands below 4 Hz they were in general much lower in the acallosal infants than in the normals.

Agenesis of Corpus Callosum↗

PubMed1985

Significance of the encephalometric parameters of human corpus callosum and medial hemispheric surface.

11 encephalometric parameters of the corpus callosum and medial hemispheric surface have been measured on 50 human brains fixed in 7% formaline solution. The measurement of linear parameters has been made by using a standardized encephalometric system of reference, based on the bicommissural line which has been widely used in neurosurgery. The applied statistical procedures have shown that the following variables are the most successful in the evaluation and prediction of the change of the midsagittal cross-sectional corpus callosum area in the following order: the thinnest part of the corpus callosum, the corpus callosum length and medial hemispheric border. Their change for the unit value causes an average change of the corpus callosum midsagittal section surface area for the value of the partial regression coefficient with which they are connected. The chosen variables explain only the 45% variability of the cross-sectional corpus callosum surface area, and the remaining variability belongs to some other variables which have not been included in present investigation. The variability of the hemispheric length (74%), the corpus callosum length (65%) and medial hemispheric border length (64%) is most adequately explained on the basis of chosen variables.

Adult↗

PubMed1993

A computerized magnetic resonance imaging study of corpus callosum morphology in schizophrenia.

The hypothesis tested was that, in schizophrenia, corpus callosum size would be reduced, particularly in the region responsible for communication between both temporal lobes. This is supported by knowledge of: (a) anatomical homotopicity and functional specialization of fibres within the corpus callosum; (b) evidence linking structural and functional deficits of the corpus callosum and left temporal lobe with schizophrenia; and (c) that temporal lobe neuronal fibres pass through the middle region of the corpus callosum. Brain area and corpus callosum areas, widths and length were measured on mid-sagittal MRI scans using a computer outlining method. Scans from 30 schizophrenics and 44 normal subjects were compared. Mid-sagittal brain area, corpus callosum area, length and anterior widths were reduced in the schizophrenic group compared with controls. A significant area difference between schizophrenics and controls was seen in the mid-corpus callosum which communicates between the temporal lobes, including the superior temporal gyri. In schizophrenics, corpus callosum area reduction was not accounted for by brain area shrinkage alone. Differences between the two groups were accounted for by comparisons between males only. These findings support the hypothesis and the possibility that localized abnormalities of bilaterally connected brain regions might have secondary effects on their homotopically distributed fibres within the corpus callosum.

Adolescent↗

PubMed2002

Wheel running behavior is impaired by both surgical section and genetic absence of the mouse corpus callosum.

Mice lacking a corpus callosum (CC) often show little or no deficit on tests of behavior. This paper reports that on highly complex bimanual motor tasks, deficits can be found. The speed of running on a wheel with irregularly spaced rungs is reduced by both hereditary absence of the CC in 129 x BALB/c recombinant mice and surgical section of the CC in genetically normal B6D2F(2) mice. The effect of CC absence appears on measures most closely related to speed, no influence exists on the amount of running over a period of 5 days. Motor behavior on a notched balance beam, on the other hand, shows clear superiority of the hybrid mice but no relation with reduced size of the CC, whether it was produced by genotype or surgery. The effect of absent CC is task dependent, but it is not obscured by developmental compensation in the recombinant mice.

Agenesis of Corpus Callosum↗

PubMed1993

CT appearances of haematomas in the corpus callosum in patients with subarachnoid haemorrhage.

Corpus callosum haematoma is a rare feature in subarachnoid haemorrhage (SAH), which may result from aneurysms of the anterior communicating artery (ACoA) or pericallosal artery (PCA). In 348 patients with aneurysmal SAH, bleeding from ACoA aneurysms in 88 cases produced no abnormality on CT in 7. Blood in the cistern of the lamina terminalis was the most frequent abnormality (76/88); haematomas of the septum pellucidum, confined to patients with ACoA aneurysms, were seen in 26 (30%). Rupture of PCA aneurysms in 12 patients gave rise to blood in the pericallosal cistern, anterior interhemispheric fissure and cistern of the lamina terminalis in 11. There was no blood in the septum pellucidum or the ventricular system in any case, but haematomas in the corpus callosum occurred in 8 (67%). In all of these, blood extended into the anterodorsal aspect of the callosum and spread posteriorly along its dorsal border. An identical, supracallosal pattern was seen in 2 patients (2.5%) with ACoA aneurysms, in whom haemorrhage was more extensive, with a large frontal lobe haematoma extending up from the cistern of the lamina terminalis in 1 and a haematoma of the septum pellucidum, with intraventricular extension in the other. In 8 patients (9%) with ACoA aneurysms a corpus callosum haematoma appeared to result from passage of blood up through the cistern of the lamina terminalis into the septum pellucidum and thence into the ventral aspect of the anterior corpus callosum; blood was present within the cistern, the septum and the ventricles.

Aneurysm, Ruptured↗

PubMed2006

Age-related degeneration of corpus callosum measured with diffusion tensor imaging.

The corpus callosum is the major commissure connecting the cerebral hemispheres, and there is evidence of its change with aging. The sub-regions of the corpus callosum (genu, rostral body, anterior midbody, posterior midbody, isthmus, splenium) respectively comprise fibers connecting heteromodal- and unimodal-associated cortical regions, and it is known that abnormalities of the corpus callosum are correlated with abnormalities in cognition and behavior. Yet, little is known about changes in the tissue characteristics of its sub-regions. We assessed age-related changes in fractional anisotropy and mean diffusivity in the sub-regions of the corpus callosum using diffusion tensor imaging. We studied 42 healthy right-handed individuals aged 21-73 years. There were no significant interactions of sex x region. Age has significant negative correlation with fractional anisotropy in the genu (P < 0.001), rostral body (P < 0.001), and isthmus (P = 0.005). Fractional anisotropy of the anterior midbody was correlated negatively with age at a trend level (P = 0.022). Age was significantly positively correlated with mean diffusivity in the genu (P = 0.001), rostral body (P = 0.002), anterior midbody (P = 0.001), and isthmus (P = 0.001). Age-related changes were detected in the sub-regions where their projection areas are thought to be vulnerable to normal aging. This suggested that fractional anisotropy and mean diffusivity values of the corpus callosum sub-regions could serve as markers of disturbance across the respective projection areas.

Adult↗