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PubMed1994

Prognostic indicators in the prenatal diagnosis of agenesis of corpus callosum.

OBJECTIVE: Our aim was to determine the accuracy of ultrasonography in the prenatal diagnosis of agenesis of the corpus callosum and to establish whether ultrasonography can provide prognostic indicators in cases of agenesis of the corpus callosum. STUDY DESIGN: Prospective ultrasonographic study of the corpus callosum in all cases during an 8-year period in which fetal cerebral ventriculomegaly was detected. RESULTS: A total of 14 cases of agenesis of the corpus callosum are reported. In seven cases agencies of the corpus callosum was an isolated finding, and in seven cases it was associated with other abnormalities. Six cases involved mendelian syndromes (3 Lissencephaly syndrome, 2 Aicardi syndrome, and 1 Andermann syndrome), and one case was associated with trisomy 13. In 5 of 14 fetuses, all male, agenesis of the corpus callosum was an isolated benign finding. The corpus callosum could never be visualized before midgestation, but diagnosis of agenesis of the corpus callosum was very accurate after 20 weeks. CONCLUSION: Prenatal ultrasonographic findings suggestive of agenesis of the corpus callosum should be followed by a careful search for associated anomalies that may indicate genetic syndromes. Isolated agenesis of the corpus callosum is often an isolated, benign finding, particularly in male fetuses. In families at risk for mendelian syndromes associated with agenesis of the corpus callosum, lack of visualization of this structure is suggestive of the diagnosis.

Agenesis of Corpus Callosum↗

PubMedDate not supplied

Tests of genetic allelism between four inbred mouse strains with absent corpus callosum.

Inbred mouse strains that lack the corpus callosum connecting the cerebral hemispheres in the adult differ from the C57BL/6J strain at several relevant but unknown loci. To identify at least one major locus that influences axon guidance, different strains showing phenotypically similar defects were crossed to test for allelism. If the F1 hybrid between two strains with the same brain defect is phenotypically normal, it is much more likely that the two strains will differ at fewer loci than will an acallosal strain and C57BL/6J. This approach proved to be very informative. Five reasonable models of inheritance involving two or three loci were assessed, and the data justified rejection of all but one hypothesis. A total of 479 mice were obtained from four inbred strains prone to absence of the corpus callosum (BALB/cWah1, BALB/cWah2, I/LnJ, and 129/ReJ), one normal strain (C57BL/6J), and 11 F1 hybrids among them. Because the size of forebrain axon bundles is generally greater in mice with larger brains, and because whole brain size is certainly polygenic, the phenotypically normal groups were used to derive a standard index of the degree of corpus callosum deficiency relative to brain size. Results demonstrated clearly that the hybrid between BALB/cWah1 and 129/ReJ is normal, whereas the crosses among the BALB/c substrains and I/LnJ yielded many mice with deficient corpus callosum. I/LnJ crossed with 129/ReJ also produced some animals with callosal defects. The data were consistent with a model in which the difference between BALB/c and 129/ReJ involves two loci, whereas the defect in I/LnJ involves homozygosity at three loci, which impairs development more severely.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗

PubMed1988

Somatosensory receptive fields of fibres in the rostral corpus callosum of the cat.

The corpus callosum is the principal neocortical commissure which transmits lateralized information between the hemispheres. The aim of the present experiment was to study the receptive field (RF) properties of somatosensory callosal fibres in the cat. The callosum was approached under direct visual control and axonic responses were recorded under N2O anaesthesia using tungsten microelectrodes or, mostly, glass micropipettes. RFs representing all the sensory submodalities tested (light touch, medium and deep pressure, joint movement and light pinches) were found to be present in the axons which travelled through the callosum. Rapidly adapting units were more common than slowly adapting ones. The axial and para-axial portions of the body accounted for about three-fifths of all RFs, followed by the head (about one-fifth), with the rest responding to stimulation of the extremities. The medial borders of most of the unilateral RFs situated on the trunk and, to a lesser degree, the head, extended to the mid-line. The results are interpreted in terms of the roles of the corpus callosum in mid-line fusion and interhemispheric transfer.

Afferent Pathways↗

PubMed1998

[Acquired lesions of the corpus callosum].

Acquired lesions of the corpus callosum may be related to tumoral, vascular, traumatic or degenerative disorders and, one must not forget, can result from surgical access. Currently, the quality of neuroimaging enables a validation or precision of anatomoclinical, neuropsychological and neurophysiological correlations established from experimental and/or autopsy data. However the "specific" signs of acquired lesions of the corpus callosum are often quite complex and may be readily overlooked or masked within a heterogeneous clinical presentation due to more or less important associated lesions of neighboring structures. Therapeutic management (tumors, arteriovenous malformations, cavernomas) depend on the nature and the extent of the lesion more than the functional nature of this inter-hemispheric commissure with an exceptional functional plasticity, particularly when the lesion is limited.

Brain Diseases↗

PubMed1995

The corpus callosum in communicating and noncommunicating hydrocephalus.

To investigate morphological changes in the corpus callosum in hydrocephalus and to correlate them with clinical findings we studied sagittal T2*-weighted cine MR images of 163 patients with hydrocephalus. The height, length and cross-sectional area of the corpus callosum were measured and related to the type of cerebrospinal fluid flow anomaly and to clinical features, especially dementia. With expansion of the lateral ventricles the corpus callosum showed mainly elevation of its body and, to a lesser degree, increase in length. Upward bowing was more pronounced in noncommunicating than in communicating hydrocephalus. Dorsal impingement on the corpus callosum by the free edge of the falx correlated with the height of the corpus callosum. Cross-sectional area did not correlate with either height, length or impingement; it was, however, the strongest anatomical discriminator between demented and nondemented patients. The area of the corpus callosum was significantly smaller in patients with white matter disease. Our findings suggest that, due to its plasticity, the corpus callosum can to some degree resist distortion in hydrocephalus. Dementia, although statistically related to atrophy of the corpus callosum, is possibly more directly related to white matter disease.

Case-Control Studies↗

PubMed2004

Traumatic lesions of corpus callosum: early multidetector CT findings.

Corpus callosum is one of the common sites of brain lesion, whose involvement is an indicator of a more severe prognosis, produced by traumatic shearing stresses resulting in diffuse axonal injury (DAI). Computed tomography (CT) in acute phase is considered to have a limited role for the detection of non-hemorrhagic or petechial hemorrhagic DAI lesions. New generation multidetector CT scanners allow faster acquisition of thinner-slice images and post-processing reformations. Three patients with severe closed head trauma underwent CT examinations using a multidetector scanner, a few hours and the day after injury. The review of original images with narrow window width and integration with reconstruction of thinner slices from raw-data and post-processing multiplanar reformations (MPR) helped to detect the onset of hypodense or predominantly hypodense areas of corpus callosum, not present at admission and afterwards confirmed by MRI.

Adolescent↗

PubMed2001

Corpus callosum agenesis.

OBJECTIVE: The objectives are to analyse corpus callosum agenesis in children with various neurological problems in a hospital set-up, and to study the neurological and systemic abnormalities associated with this condition. METHODS: The children with various neurological problems who underwent computerized tomography brain from January 1993 to December 1997, and were found to have corpus callosum agenesis, formed the subjects of this study. These children were examined for any syndromic association, congenital infections or metabolic defects. RESULTS: Out of 2164 children who underwent computerized tomography brain, 22 had corpus callosum agenesis (1%). Most cases were not syndromic and 64% were males. Epileptic disorders were noted in about one third of cases. CONCLUSION: Corpus callosum agenesis is an important anomaly in children with neurodevelopment handicaps, usually detected by neuroradiology.

Agenesis of Corpus Callosum↗

PubMed2005

Cerebral and corpus callosum atrophy in systemic lupus erythematosus.

OBJECTIVE: To determine cerebral and corpus callosum volumes in patients with systemic lupus erythematosus (SLE), using semiautomatic magnetic resonance imaging (MRI) volumetric measurements, and to determine possible relationships between a reduction in cerebral volume and disease duration, total corticosteroid dose, neuropsychiatric manifestations, and the presence of antiphospholipid antibodies. METHODS: We studied 115 consecutive patients with SLE and 44 healthy volunteers. A complete clinical, laboratory, and neurologic evaluation was performed. MRI scans were obtained through a standardized protocol. Sagittal T1-weighted images were used for semiautomatic volumetric measurements. We compared SLE patients with controls using the 2-sample t-test. Analysis of variance was used to test for differences between groups, followed by Tukey's post hoc test for pairwise comparisons, when necessary. Linear regression was used to analyze the association between cerebral atrophy and disease duration and total corticosteroid dose. RESULTS: Cerebral and corpus callosum volumes were significantly smaller in patients with SLE compared with healthy volunteers (P < 0.001). Reduced cerebral and corpus callosum volumes were related to disease duration (P < 0.001). Patients with a history of central nervous system (CNS) involvement more frequently had a reduction in cerebral and corpus callosum volumes (P < 0.001). Patients with cognitive impairment had significantly reduced corpus callosum and cerebral volumes when compared with SLE patients without cognitive impairment (P = 0.001). Cerebral and corpus callosum volumes were not associated with the total corticosteroid dose or the presence of antiphospholipid antibodies. CONCLUSION: In patients with SLE, a reduction in cerebral and corpus callosum volumes is associated with disease duration, a history of CNS involvement, and cognitive impairment. The total corticosteroid dose and the presence of antiphospholipid antibodies were not associated with more pronounced atrophy.

Adult↗

PubMed1994

Corpus callosum in developmentally retarded infants.

The development of the corpus callosum was examined by magnetic resonance imaging in developmentally retarded infants ranging in age from 1-13 months. Results were compared with those of normal infants. Eighteen magnetic resonance imaging studies were performed on 18 developmentally retarded infants. Fifty-four magnetic resonance imaging studies were performed on 38 normally developed infants. The thickness of the corpus callosum was measured at a point one-third of the length of the entire corpus callosum from the most anterior aspect of the genu. The development of the corpus callosum was related to aging in both groups. There was significant difference in the thickening of the corpus callosum between normal and developmentally retarded infants.

Birth Weight↗

PubMed2005

The role of the corpus callosum in interhemispheric transfer of information: excitation or inhibition?

The corpus callosum is the major neural pathway that connects homologous cortical areas of the two cerebral hemispheres. The nature of how that interhemispheric connection is manifested is the topic of this review; specifically, does the corpus callosum serve to communicate an inhibitory or excitatory influence on the contralateral hemisphere? Several studies take the position that the corpus callosum provides the pathway through which a hemisphere or cortical area can inhibit the other hemisphere or homologous cortical area in order to facilitate optimal functional capacity. Other studies suggest that the corpus callosum integrates information across cerebral hemispheres and thus serves an excitatory function in interhemispheric communication. This review examines these two contrasting theories of interhemispheric communication. Studies of callosotomies, callosal agenesis, language disorders, theories of lateralization and hemispheric asymmetry, and comparative research are critically considered. The available research, no matter how limited, primarily supports the notion that the corpus callosum serves a predominantly excitatory function. There is evidence, however, to support both theories and the possibility remains that the corpus callosum can serve both an inhibitory and excitatory influence on the contralateral hemisphere.

Arousal↗

PubMed1995

Inhibitory and excitatory interhemispheric transfers between motor cortical areas in normal humans and patients with abnormalities of the corpus callosum.

Transcranial magnetic stimulation of the motor cortex was performed in 10 normal subjects and 10 patients with radiographical abnormalities of the corpus callosum. Seven patients had a complete or partial agenesis or hypoplasia of the corpus callosum, two had a thin corpus callosum due to hydrocephalus or white matter degeneration and one had a circumscript contusion lesion of the corpus callosum. The patients served as a clinical model to investigate transcallosal influences on excitatory and inhibitory effects of motor cortex stimulation and to assess the potential diagnostic use of interhemispheric conduction studies and the contribution of interhemispheric interaction on transcranially elicited contralateral excitatory and inhibitory motor responses. Stimulation over one motor cortex suppressed tonic voluntary electromyographic activity in ipsilateral hand muscles in all subjects with preserved anterior half of the trunk of the corpus callosum. Since this suppression was lacking or had a delayed onset latency in patients with absence or abnormalities of the anterior half of the trunk of the corpus callosum it can be concluded that it is due to a transcallosal inhibition (Ti) of the opposite motor cortex mediated by fibres passing through this part of the corpus callosum. In normal subjects Ti had an mean onset latency of 36.1 +/- 3.5 ms (SD) and a duration of 24.5 +/- 3.9 ms. The calculated mean transcallosal conduction time was 13 ms. The threshold of Ti recorded in muscles ipsilateral to stimulation tended to be higher than the one for eliciting excitatory contralateral motor responses (56 +/- 6% versus 46 +/- 10% maximum stimulator output). Cortical thresholds (at rest) for contralateral excitatory hand motor responses were higher in patients with developmental abnormalities of the corpus callosum than in normals (66 +/- 17% versus 46 +/- 10% maximum stimulator output), which probably reflects also a facilitatory transcallosal interaction of both motor cortices in normals. In contrast, facilitation of cortically elicited motor responses in one hand by strong contraction of the other hand was the same in the patients with agenesis of the corpus callosum and normals, which suggests that this facilitatory spread takes place on a spinal rather than on a cortical level. Central motor latencies and amplitudes of contralateral hand motor responses were the same in patients with developmental abnormalities of the corpus callosum and normals (6.1 +/- 0.7 ms versus 6.3 +/- 0.7 ms and 6.7 +/- 2.4 mV versus 6.6 +/- 2.9 mV) so that callosal transfers do not seem to influence corticospinal conduction properties.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed2004

Molecular screening of the ZFHX1B gene in prenatally diagnosed isolated agenesis of the corpus callosum.

OBJECTIVE: Agenesis of the corpus callosum (ACC) is the most common malformation of the central nervous system and may be associated with mental retardation. ACC is found in 40% of the cases of Mowat-Wilson syndrome (MWS), a polytopic embryonic defect including a distinctive facial gestalt, severe mental retardation, epilepsy and postnatal microcephaly as constant features. Other manifestations involve Hirschsprung disease, cardiac defects, renal abnormalities and hypospadias. Among this broad spectrum of malformations recently associated with haploinsufficiency of the zinc finger homeobox 1B gene (ZFHX1B), ACC can therefore be the only feature to be detected prenatally. Thus, we studied a group of 18 fetuses terminated for ACC and performed mutational analysis of the ZFHX1B gene in six selected cases. METHODS: Diagnosis of agenesis of the ACC was performed by prenatal echography survey. Screening for ZFHX1B deletions was performed by poly (CA) microsatellite markers studies and real-time semi-quantitative PCR. Mutational analysis was performed by single-strand conformation polymorphisms analysis (SSCP). RESULTS: Neither deletion encompassing the ZFHX1B locus nor mutation could be detected in any of the six fetuses analysed. CONCLUSION: ZFHX1B is not a major gene in isolated ACC. However, analysis of MWS should be considered in the differential diagnosis of ACC, especially when the facial features raise the possibility of MWS.

Agenesis of Corpus Callosum↗

PubMed1996

A mother and daughter with agenesis of the corpus callosum.

A mother and daughter with agenesis of the corpus callosum are reported. There have only been 11 prior case reports of the familial occurrence of agenesis of the corpus callosum in the absence of extracranial malformations. Most of these reports have described familial occurrence among siblings. The present communication is only the second description of a parent and child with agenesis of the corpus callosum. A review of the published cases of familial syndrome unrelated agenesis of the corpus callosum indicates that both mental, developmental and neurologic disorders in cases involving parent and child are milder than those in cases involving siblings. Of additional interest, electroencephalography performed in this patient during sleep, frequently revealed bilateral asynchronous sleep spindles, supporting the hypothesis of previous investigators that the synchronicity of sleep spindles requires intact intercerebral commissures.

Agenesis of Corpus Callosum↗

PubMed1985

[Magnetic resonance imaging in agenesis of the corpus callosum].

The recent use of computed tomography (CT) scan is providing an easy diagnoses of agenesis of corpus callosum which had been difficult to diagnose only by clinical signs and symptoms. Since, more neuropsychological studies on agenesis of corpus callosum are being done, clinical details of agenesis of corpus callosum are being clarified. We examined magnetic resonance imaging (MRI) on 3 patients who were suspected to have agenesis of corpus callosum by CT scan. And we studied the usefulness of MRI in agenesis of corpus callosum. Case 1. We studied a thirty-two-year-old right-handed man with a one-year history of amyotrophic lateral sclerosis. He had no callosal disconnection syndrome. CT scan on horizontal view showed dilated third ventricle, the dilatation of the occipital horns and wide separation of the lateral ventricles. On coronal view, CT scan showed the absence of the corpus callosum, the concave mesial borders of the lateral ventricle, the dilatation of the third ventricle and its abnormal dorsal extent(bat-wing appearance). On sagittal MRI (the inversion recovery technique), the corpus callosum was absent and the convolutions and sulci were arranged radically centering the third ventricle (radial distribution). But the anterior commissure was preserved. Case 2. We studied a fourty-one-year-old right-handed man with a seven-year history of hyper ventilation syndrome. He had no callosal disconnection syndrome. CT scan showed the similar findings as those of case 1. On sagittal MRI (the inversion recovery technique), the corpus callosum was absent, and the convolutions and sulci showed radial distribution. But the anterior commissure was preserved.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

[Vascularization of the corpus callosum in humans].

The blood supply of the corpus callosum is studied in 20 brains by injecting the vascular system with gelatinous Indian ink. The arterial vascularization derives mainly from the anterior cerebral arteries, accessed from the median artery of the corpus callosum or from the terminal and choroidal branches of the posterior cerebral arteries. The various arteries give off perforating branches which are direct or indirect, short, of middle length or long. All these arteries concentrate on the peripheral wall of the corpus callosum. Inside of it these various arteries give off numerous terminal and collateral branches running between the nervous fibres and forming a characteristic vascular network which nourishes the capillary network. The venous vascularization of the corpus callosum is tributary to the deep venous system of the brain and concentrates on the central wall of the commissure.

Arterioles↗

PubMed1999

Diffusion-weighted and magnetization transfer imaging of the corpus callosum in Alzheimer's disease.

We investigated structural changes of the corpus callosum in patients with Alzheimer's disease (AD) using sagittal diffusion-weighted (DW) and magnetization transfer (MT) imaging. Patients with AD (n=23) had a significantly decreased area only in the posterior portion of the corpus callosum. Apparent diffusion coefficient (ADC) values perpendicular to the commisural fiber orientation were significantly higher in the anterior portion of the corpus callosum without definite atrophy, as well as in the posterior portion with significant atrophy, in patients with AD than in controls (n=16) and thus diffusion in these regions showed a significantly lower degree of anisotropy in patients than in controls. MT ratios were also significantly lower in patients with AD in the anterior and posterior portions of the corpus callosum than in controls. These findings probably reflect structural changes in the corpus callosum including axonal loss and/or demyelination. DW and MT imagings may be useful in detecting degeneration of the corpus callosum in AD.

Aged↗

PubMed1978

Agenesis of corpus callosum in calves.

Agenesis of the corpus callosum is a rare brain defect in cattle, and was described in two calves. It was characterized by the total absence of the corpus callosum, septum pellucidum and hippocampal commissure. Fornices were present but separated. Both calves also had moderate internal hydrocephalus, micrencephaly and a CSF-filled cyst in the longitudinal fissure dorsal to the thalamus. Clinical signs were not specific. Etiology and pathogenesis are unknown. No evidence of inflammation or inheritance was found as cause of the defect.

Agenesis of Corpus Callosum↗

PubMed1980

[Shape and size of the corpus callosum and the septum pellucidum].

The mean are of the Corpus callosum at median sagittal sections of 100 brains of adults comes to 622 (330 to 900) mm2. The Corpus callosum has a mean length of 73.7 (62 to 86) mm and a mean height of 23.06 (16 to 31) mm. The Genu corporis callosi has a mean thickness of 11.68 mm and the Splenium of 11.98 mm. The Truncus has a greatest thickness of 6.68 and a smallest thickness of 4.49 mm on an average. In the rostral third the Truncus has a mean thickness of 6.11 mm, the middle of the Corpus callosum of 5.66 mm and the support of the Fornix 5.75 mm. The Corpus fornicis supports in the mean of 48.45 mm behind the rostal end of the Genu corporis of the underneath area of the Corpus callosum. This is observed in 77% in the third, in 19% in the fourth and in 4% in the second quarter of the Corpus callosum. The Septum pellucidum has a mean surface area of 292 (100 to 700) mm2 at median sagittal sections.

Adult↗