Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.182
Filtrar
1.
J Affect Disord ; 251: 280-286, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30953893

RESUMO

BACKGROUND: Aberrant functional and structural connectivity are considered to be involved in the underlying neural mechanism of generalized anxiety disorder (GAD). However, alterations in functional and structural interactions between the bilateral hemispheres are rarely examined. The current study aimed to characterized interhemispheric resting-state functional connectivity and white matter microstructural integrity of the corpus callosum in patients with GAD. METHODS: Resting-state Blood oxygen level-dependent and diffusion tensor image were acquired for patients with GAD and healthy subjects. The two groups were matched in age, gender, education years. The voxel-mirrored homotopic connectivity (VMHC) of whole brain and white matter integrity of the corpus callosum (CC) were compared between the two groups. Their correlations with clinical measures were further performed. RESULTS: Compare to controls, decreased resting-state VMHC were found in the precentral gyrus, middle cingulate gyrus and insula/putamen in patients with GAD. No regions of increased VMHC were detected in GAD. Compared to controls, GAD patients showed decreased fractional anisotropy (FA) values in CC2. In GAD group, further Pearson's correlation analyses showed that VMHC of the midcingulate gyrus positively correlated with FA of CC2, FA of CC2 negatively correlated with anxiety severity. Further mediation analyses demonstrated that attenuated VMHC in bilateral midcingulate gyrus partly mediated the association between white matter integrity of CC2 sub-region and anxiety severity. CONCLUSION: Our findings suggested impairment of interhemispheric coordination in GAD. Moreover, disrupted interhemispheric connectivity correlated with anxiety severity in GAD. Our findings provided a novel clue about the neural mechanism of GAD, and may contribute to further deep exploration and treatment of GAD. LIMITATIONS: The study was lack of comparison with non-GAD anxiety disorders.


Assuntos
Transtornos de Ansiedade/fisiopatologia , Córtex Cerebral/fisiopatologia , Corpo Caloso/fisiopatologia , Adulto , Anisotropia , Transtornos de Ansiedade/diagnóstico por imagem , Estudos de Casos e Controles , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiologia , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/fisiologia , Imagem de Tensor de Difusão , Feminino , Giro do Cíngulo/fisiologia , Giro do Cíngulo/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Valores de Referência
2.
J Hum Genet ; 64(4): 341-346, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30692597

RESUMO

The genetic causes of combined pituitary hormone deficiency remain elusive in most patients. Recently, incompletely penetrant heterozygous mutations in ROBO1 have been described in patients with pituitary stalk interruption syndrome. Herein, we identified a novel homozygous slice site mutation in ROBO1 (c.1342+1G>A) using a trio whole-exome sequencing strategy in a 5-year-old Japanese boy who had combined pituitary hormone deficiency, psychomotor developmental delay, severe intellectual disability, sensorineural hearing loss, strabismus, and characteristic facial features, including a broad forehead, micrognathia, and arched eyebrows. Magnetic resonance imaging delineated anterior pituitary hypoplasia, ectopic posterior pituitary, invisible pituitary stalk, thinning of the corpus callosum, and hypoplasia of the pons and midbrain. The phenotypically normal parents (first cousins) were heterozygous for the mutation. The results provide further evidence of ROBO1 being involved in the development of the pituitary gland. A recessive mutation of ROBO1 is a potential novel cause of a syndromic disorder associated with combined pituitary hormone deficiency.


Assuntos
Perda Auditiva Neurossensorial/genética , Hipopituitarismo/genética , Deficiência Intelectual/genética , Proteínas do Tecido Nervoso/genética , Receptores Imunológicos/genética , Pré-Escolar , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/fisiopatologia , Perda Auditiva Neurossensorial/complicações , Perda Auditiva Neurossensorial/diagnóstico por imagem , Perda Auditiva Neurossensorial/fisiopatologia , Humanos , Hipopituitarismo/complicações , Hipopituitarismo/diagnóstico por imagem , Hipopituitarismo/fisiopatologia , Deficiência Intelectual/complicações , Deficiência Intelectual/diagnóstico por imagem , Deficiência Intelectual/fisiopatologia , Imagem por Ressonância Magnética , Masculino , Mutação , Sítios de Splice de RNA/genética , Sequenciamento Completo do Exoma
4.
PLoS One ; 13(6): e0196607, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29864120

RESUMO

Preterm children often have language problems. This atypical language development is probably due to atypical brain development. We conducted a systematic review to provide an overview of the extensive and diverse scientific literature on the relations between language outcome and underlying brain structures in school-aged preterm-born children. Embase, Medline Ovid, Web of Science, Cochrane central and Google scholar were searched for relevant studies. Inclusion criteria were: cases are school-aged preterm children; structural MRI (T1- and T2-weighted sequences) or DTI used in combination with a neurocognitive language test; publication in an English-language peer-reviewed journal. Correlational measures between language scores and brain volume or fractional anisotropy of a brain structure were extracted. 23 studies were included. The relations between oral language, verbal fluency and/or written language and MRI/DTI measurements of white matter, gray matter, cerebellum, corpus callosum and/or the fasciculi are presented. Oral language skills and verbal fluency appear to be related to the corpus callosum. Oral language skills are also related to the uncinate fasciculus. There seems to be no clear relation between cerebellar development and verbal fluency skills. Not one single brain area is responsible for atypical language development, but several brain areas and their connections are essential. For future research it is recommended to relate brain areas to oral language skills on a microstructural level in preterm children. We also recommend to use language tests in which it is possible to distinguish between several language domains, such as perceptive and expressive language.


Assuntos
Corpo Caloso , Recém-Nascido Prematuro , Transtornos do Desenvolvimento da Linguagem , Desenvolvimento da Linguagem , Criança , Corpo Caloso/patologia , Corpo Caloso/fisiopatologia , Feminino , Humanos , Recém-Nascido , Transtornos do Desenvolvimento da Linguagem/patologia , Transtornos do Desenvolvimento da Linguagem/fisiopatologia , MEDLINE , Masculino
5.
Proc Natl Acad Sci U S A ; 115(27): E6339-E6346, 2018 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-29915074

RESUMO

Recent reports have begun to elucidate mechanisms by which learning and experience produce white matter changes in the brain. We previously reported changes in white matter surrounding the anterior cingulate cortex in humans after 2-4 weeks of meditation training. We further found that low-frequency optogenetic stimulation of the anterior cingulate in mice increased time spent in the light in a light/dark box paradigm, suggesting decreased anxiety similar to what is observed following meditation training. Here, we investigated the impact of this stimulation at the cellular level. We found that laser stimulation in the range of 1-8 Hz results in changes to subcortical white matter projection fibers in the corpus callosum. Specifically, stimulation resulted in increased oligodendrocyte proliferation, accompanied by a decrease in the g-ratio within the corpus callosum underlying the anterior cingulate cortex. These results suggest that low-frequency stimulation can result in activity-dependent remodeling of myelin, giving rise to enhanced connectivity and altered behavior.


Assuntos
Ansiedade/fisiopatologia , Corpo Caloso/fisiopatologia , Estimulação Encefálica Profunda , Optogenética , Substância Branca/fisiopatologia , Animais , Ansiedade/patologia , Corpo Caloso/patologia , Camundongos , Substância Branca/patologia
6.
Brain Dev ; 40(8): 719-723, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29622280

RESUMO

PURPOSE: Polymicrogyria, a malformation of the cerebral cortex, frequently causes epilepsy. Diffuse bilateral polymicrogyria (DBP) is related to poor epilepsy prognosis, but most patients with DBP are not good candidates for resective epilepsy surgery and effectiveness of corpus callosotomy (CC), a palliative surgery, for patients without resective epileptogenic cortices, has not been established in DBP. Because CC might be effective against DBP-related epilepsy, we conducted total CC in three pediatric DBP cases. METHODS: Case 1. A girl developed epilepsy at 3 months of age, with focal versive seizures and epileptic spasms. The electroencephalogram (EEG) showed a suppression-burst pattern. Total CC was performed at 6 months of age. Case 2. A female infant developed epilepsy on the day of birth, exhibiting epileptic spasms, generalized tonic-clonic seizures, and eye-deviating seizures. She had a history of clusters of tonic seizures. Total CC was performed at 1 year and 2 months of age. After CC, the epileptic focus of the tonic seizures was identified; a secondary resective surgery was conducted. Case 3. A girl developed multiple types of seizures at 3 years of age. Frequent atypical absence status was refractory to antiepileptic drugs. Total CC was conducted at 8 years of age. RESULTS: Case 1: Frequencies of both seizure types decreased. The background EEG changed to continuous high-voltage slow waves. Case 2: Clusters of tonic seizures were well-controlled. Case 3: Atypical absence seizures completely disappeared. CONCLUSION: CC could be effective for patients with DBP, whose habitual seizures include epileptic spasms and absence seizures.


Assuntos
Corpo Caloso/cirurgia , Polimicrogiria/cirurgia , Criança , Pré-Escolar , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/fisiopatologia , Feminino , Humanos , Polimicrogiria/diagnóstico por imagem , Polimicrogiria/fisiopatologia , Convulsões/diagnóstico por imagem , Convulsões/fisiopatologia , Convulsões/cirurgia
7.
Brain Dev ; 40(7): 592-595, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29606344

RESUMO

BACKGROUND: Neurological manifestations caused by hypoglycemia range from reversible focal deficits and transient encephalopathy to irreversible coma or death. Recently, high signal intensity lesions in the splenium of the corpus callosum on diffusion-weighted magnetic resonance imaging were reported in adults experiencing hypoglycemia. However, patients presenting with agraphia are rare. SUBJECT AND METHODS: We examined a 17-year-old left-handed female patient with type 1 diabetes who exhibited transient left agraphia with a reversible splenium lesion of the corpus callosum on diffusion-weighted imaging caused by hypoglycemia, which was improved with blood glucose management alone. CONCLUSION: This rare case indicates that agraphia, a sign of callosal disconnection syndrome, can result from a reversible splenial lesion of the corpus callosum caused by hypoglycemia.


Assuntos
Agrafia/diagnóstico por imagem , Agrafia/etiologia , Corpo Caloso/diagnóstico por imagem , Hipoglicemia/complicações , Hipoglicemia/diagnóstico por imagem , Adolescente , Agrafia/fisiopatologia , Agrafia/terapia , Corpo Caloso/fisiopatologia , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/diagnóstico por imagem , Diabetes Mellitus Tipo 1/fisiopatologia , Diabetes Mellitus Tipo 1/terapia , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Hipoglicemia/fisiopatologia , Hipoglicemia/terapia
8.
Biomed Res Int ; 2018: 6795397, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29511689

RESUMO

This study compared white matter development in prelingually deaf and normal-hearing children using a tract-based spatial statistics (TBSS) method. Diffusion tensor imaging (DTI) was performed in 21 prelingually deaf (DEAF group) and 20 normal-hearing (HEAR group) subjects aged from 1.7 to 7.7 years. Using TBSS, we evaluated the regions of significant difference in fractional anisotropy (FA) between the groups. Correlations between FA values and age in each group were also analyzed using voxel-wise correlation analyses on the TBSS skeleton. Lower FA values of the white matter tract of Heschl's gyrus, the inferior frontooccipital fasciculus, the uncinate fasciculus, the superior longitudinal fasciculus, and the forceps major were evident in the DEAF group compared with those in the HEAR group below 4 years of age, while the difference was not significant in older subjects. We also found that age-related development of the white matter tracts may continue until 8 years of age in deaf children. These results imply that development of the cerebral white matter tracts is delayed in prelingually deaf children.


Assuntos
Cérebro/diagnóstico por imagem , Surdez/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Substância Branca/diagnóstico por imagem , Anisotropia , Cérebro/fisiopatologia , Criança , Pré-Escolar , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/fisiopatologia , Surdez/fisiopatologia , Feminino , Humanos , Lactente , Masculino , Substância Branca/fisiopatologia
9.
MAGMA ; 31(4): 483-499, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29397450

RESUMO

OBJECTIVE: Schizophrenia (SZ) is a psychiatric disorder that especially affects individuals during their adolescence. There is a need to study the subanatomical regions of SZ brain on magnetic resonance images (MRI) based on morphometry. In this work, an attempt was made to analyze alterations in structure and texture patterns in images of the SZ brain using the level-set method and Laws texture features. MATERIALS AND METHODS: T1-weighted MRI of the brain from Center of Biomedical Research Excellence (COBRE) database were considered for analysis. Segmentation was carried out using the level-set method. Geometrical and Laws texture features were extracted from the segmented brain stem, corpus callosum, cerebellum, and ventricle regions to analyze pattern changes in SZ. RESULTS: The level-set method segmented multiple brain regions, with higher similarity and correlation values compared with an optimized method. The geometric features obtained from regions of the corpus callosum and ventricle showed significant variation (p < 0.00001) between normal and SZ brain. Laws texture feature identified a heterogeneous appearance in the brain stem, corpus callosum and ventricular regions, and features from the brain stem were correlated with Positive and Negative Syndrome Scale (PANSS) score (p < 0.005). CONCLUSION: A framework of geometric and Laws texture features obtained from brain subregions can be used as a supplement for diagnosis of psychiatric disorders.


Assuntos
Biomarcadores/análise , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Imagem por Ressonância Magnética , Esquizofrenia/diagnóstico por imagem , Esquizofrenia/fisiopatologia , Adulto , Algoritmos , Análise por Conglomerados , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/fisiopatologia , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Processamento de Imagem Assistida por Computador , Masculino , Reconhecimento Automatizado de Padrão , Software
10.
Neurobiol Aging ; 65: 69-76, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29407468

RESUMO

Older adults typically experience reductions in the structural integrity of the anterior channels of the corpus callosum. Despite preserved structural integrity in central and posterior channels, many studies have reported that interhemispheric transfer, a function attributed to these regions, is detrimentally affected by aging. In this study, we use a constrained event-related potential analysis in the theta and alpha frequency bands to determine whether interhemispheric transfer is affected in older adults. The crossed-uncrossed difference and lateralized visual evoked potentials were used to assess interhemispheric transfer in young (18-27) and older adults (63-80). We observed no differences in the crossed-uncrossed difference measure between young and older groups. Older adults appeared to have elongated transfer in the theta band potentials, but this effect was driven by shortened contralateral peak latencies, rather than delayed ipsilateral latencies. In the alpha band, there was a trend toward quicker transfer in older adults. We conclude that older adults do not experience elongated interhemispheric transfer in the visuomotor or visual domains and that these functions are likely attributed to posterior sections of the corpus callosum, which are unaffected by aging.


Assuntos
Envelhecimento/fisiologia , Envelhecimento/psicologia , Corpo Caloso/fisiologia , Corpo Caloso/fisiopatologia , Transmissão Sináptica/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Potenciais Evocados/fisiologia , Potenciais Evocados Visuais/fisiologia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
11.
Acta Neuropathol Commun ; 6(1): 4, 2018 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-29301568

RESUMO

Proteoglycans are promising therapeutic targets in Multiple Sclerosis (MS), because they regulate many aspects of the immune response. This was studied using surfen, an agent that binds both heparan sulphate proteoglycans (HSPGs) and chondroitin sulphate proteoglycans (CSPGs). Initial cell culture work on bone marrow derived macrophages (BMDMs) found that surfen reduced concentrations of the chemokines CCL2, CCL4 and CCL5, with reduced messenger (m)RNA expression for Tumor Necrosis Factor, IL-6, IL-1ß and inducible nitric oxide synthase. These data were further explored using Experimental Autoimmune Encephalomyelitis (EAE) in mice. Surfen reduced clinical signs during EAE when administered from disease onset, and reduced infiltration by CD4 positive T cells and macrophages into the central nervous system. These mice also showed reduced mRNA expression for the chemokines CCL3 and CCL5, with reduced concentrations of CCL2, CCL3 and CCL5. During EAE, surfen treatment induced a persistent increase in Interleukin (IL)-4 concentrations which may enhance T helper 2 responses. During EAE, surfen treatment reduced mRNA expression for HSPGs (NDST1, agrin, syndecan-4, perlecan, serglycin, syndecan-1) and the CSPG versican. By contrast, surfen increased mRNA expression for the CSPG aggrecan, with no effect on neurocan. During EAE, significant positive correlations were found between mRNA expression and clinical score for syndecan-4, serglycin and syndecan-1 and a significant negative correlation for aggrecan. These correlations were absent in surfen treated mice. Repair in the later stages of MS involves remyelination, which was modeled by injecting lysolecithin (lysophosphatidylcholine, LPC) into mouse corpus callosum to create regions of demyelination. When surfen was injected 2 days after LPC, it delayed remyelination of the lesions, but had no effect when injected 7 days after LPC. The delayed remyelination was associated with local increases in CSPG expression. Therefore surfen suppresses inflammation but inhibits remyelination in these models. A mechanism in common may be increased CSPG expression.


Assuntos
Encefalomielite Autoimune Experimental/tratamento farmacológico , Fatores Imunológicos/farmacologia , Inflamação/tratamento farmacológico , Remielinização/efeitos dos fármacos , Ureia/análogos & derivados , Animais , Medula Óssea/efeitos dos fármacos , Medula Óssea/patologia , Medula Óssea/fisiologia , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD4-Positivos/fisiologia , Células Cultivadas , Quimiocinas/metabolismo , Corpo Caloso/efeitos dos fármacos , Corpo Caloso/patologia , Corpo Caloso/fisiopatologia , Encefalomielite Autoimune Experimental/patologia , Encefalomielite Autoimune Experimental/fisiopatologia , Feminino , Fatores Imunológicos/administração & dosagem , Inflamação/patologia , Inflamação/fisiopatologia , Macrófagos/efeitos dos fármacos , Macrófagos/patologia , Macrófagos/fisiologia , Camundongos Endogâmicos C57BL , Proteoglicanas/metabolismo , RNA Mensageiro/metabolismo , Remielinização/fisiologia , Medula Espinal/efeitos dos fármacos , Medula Espinal/patologia , Medula Espinal/fisiopatologia , Ureia/efeitos adversos , Ureia/farmacologia
12.
J Int Med Res ; 46(3): 1277-1281, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29322880

RESUMO

Background Reversible splenial lesion syndrome is a distinct entity radiologically characterized by a reversible lesion in the splenium of the corpus callosum. According to previous reports, this condition may be associated with antiepileptic drug use or withdrawal. We herein report a case of reversible splenial lesion syndrome associated with oxcarbazepine withdrawal. Case Report A 39-year-old man presented with an 8-year history of epileptic seizures. During the previous 3 years, he had taken oxcarbazepine irregularly. One week prior to admission, he withdrew the oxcarbazepine on his own, and the epilepsy became aggravated. Magnetic resonance imaging (MRI) revealed an isolated lesion in the splenium of the corpus callosum with slight hypointensity on T1-weighted imaging and slight hyperintensity on T2-weighted imaging. Regular oxcarbazepine was prescribed. Over a 5-month follow-up period, repeat MRI showed that the abnormal signals in the splenium of the corpus callosum had completely disappeared. Conclusion Reversible splenial lesion syndrome is a rare clinicoradiological disorder that can resolve spontaneously with a favorable outcome. Clinicians should be aware of this condition and that oxcarbazepine withdrawal is a possible etiological factor.


Assuntos
Anticonvulsivantes/efeitos adversos , Encefalopatias/induzido quimicamente , Carbamazepina/análogos & derivados , Corpo Caloso/patologia , Síndrome de Abstinência a Substâncias/fisiopatologia , Adulto , Encefalopatias/diagnóstico por imagem , Encefalopatias/patologia , Encefalopatias/fisiopatologia , Carbamazepina/efeitos adversos , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/fisiopatologia , Gerenciamento Clínico , Humanos , Imagem por Ressonância Magnética , Masculino , Oxcarbazepina , Convulsões/tratamento farmacológico , Convulsões/fisiopatologia , Síndrome
13.
Clin Neurophysiol ; 129(1): 1-12, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29127826

RESUMO

OBJECTIVE: Given the presence of execution deficits after stroke, it is difficult to determine if patients with stroke have deficits in motor skill learning with the paretic arm. Here, we controlled for execution deficits while testing practice effects of the paretic arm on motor skill learning, long-term retention, and corticospinal excitability. METHODS: Ten patients with unilateral stroke and ten age-matched controls practiced a kinematic arm skill for two days and returned for retention testing one-day and one-month post-practice. Motor skill learning was quantified as a change in speed-accuracy tradeoff from baseline to retention tests. Transcranial magnetic stimulation (TMS) was used to generate an input-output curve of the ipsilesional motor cortex (M1), and measure transcallosal inhibition from contralesional to ipsilesional M1. RESULTS: While the control group had greater overall accuracy than the stroke group, both groups showed comparable immediate and long-term improvements with practice. Skill improvements were accompanied by greater excitability of the ipsilesional corticospinal system and reduced transcallosal inhibition from contralesional to ipsilesional M1. CONCLUSIONS: When execution deficits are accounted for, patients with stroke demonstrate relatively intact motor skill learning with the paretic arm. Paretic arm learning is accompanied by modulations in corticospinal and transcallosal mechanisms. SIGNIFICANCE: Functional recovery after stroke relies on ability for skill learning and the underlying mechanisms.


Assuntos
Aprendizagem , Destreza Motora , Paresia/fisiopatologia , Reabilitação do Acidente Vascular Cerebral/métodos , Idoso , Braço/fisiopatologia , Estudos de Casos e Controles , Corpo Caloso/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Motor/fisiopatologia , Paresia/reabilitação , Estimulação Magnética Transcraniana/métodos
14.
Neurosci Lett ; 665: 43-47, 2018 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-29174639

RESUMO

Morphometric neuroimaging studies on healthy adult individuals regularly report a positive association between intelligence test performance (IQ) and structural properties of the corpus callosum (CC). At the same time, studies examining the effect of callosotomy on epilepsy patients report only negligible changes in IQ as result of the surgery, partially contradicting the findings of the morphometry studies. Objective of the present meta-analysis of individual participant data (IPD) of 87 cases from 16 reports was to re-investigate the effect of callosotomy on full scale IQ as well as on the verbal and performance subscale under special consideration of two possible moderating factors: pre-surgical IQ levels and the extent of the surgery (complete vs. anterior transsection). The main finding was that callosotomy selectively affects performance IQ, whereby the effect is modulated by the pre-surgical level of performance. Patients with an above-median pre-surgery performance IQ level show a significant average decrease of -5.44 (CI95%: - 8.33 to - 2.56) IQ points following the surgery, while the below-median group does not reveal a significant change in IQ (mean change: 1.01 IQ points; CI95%: -1.83 to 3.86). Thus, the present analyses support the notion that callosotomy has a negative effect on the patients' performance IQ, but only in those patients, who at least have an average performance levels before the surgery. This observation also lends support to the findings of previous morphometry studies, indicating that the frequently observed CC-IQ correlation might indeed reflect a functional contribution of callosal interhemispheric connectivity to intelligence-test performance.


Assuntos
Corpo Caloso/fisiopatologia , Epilepsia/fisiopatologia , Testes de Inteligência/estatística & dados numéricos , Adolescente , Adulto , Criança , Corpo Caloso/cirurgia , Craniotomia , Eletroencefalografia/métodos , Epilepsia/cirurgia , Feminino , Humanos , Masculino , Estatística como Assunto
15.
Strabismus ; 26(1): 22-27, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29279026

RESUMO

PURPOSE: Besides chiasmal hemidecussation, interhemispheric connections are likely important in human binocularity. The corpus callosum (CC) is the major fiber bundle in the mammalian brain which mostly connects homologous cortical areas in the two hemispheres. Visual interhemispheric connections were found abnormal in strabismic cats. No studies have investigated these pathways in humans with infantile strabismus. METHODS: Diffusion tensor imaging was used in four subjects with infantile esotropia (IE) and nine control subjects with normal binocularity, in order to study interhemispheric fibers in the CC connecting the right and left primary visual cortical areas. RESULTS: The number of callosal fibers linking both visual cortical areas between the hemispheres was found to be higher in subjects with IE. Also in IE, the amount of visual callosal fibers found after analysis from the primary visual cortical areas on one side appeared significantly different from the amount starting from the contralateral primary visual areas. The distribution area on one side is wider. CONCLUSION: We show callosal visual fibers to be abnormal in human IE. Subjects with IE showed abnormal numbers of transcallosal fibers connecting the visual cortical areas on both sides which likely results from an abnormal elimination process during development. Pruning of these fibers in IE favors the side of the visual cortex ipsilateral to the dominant eye. This study underlines the likely role of the CC in the development of human binocularity.


Assuntos
Corpo Caloso/diagnóstico por imagem , Esotropia/diagnóstico por imagem , Córtex Visual/diagnóstico por imagem , Vias Visuais/diagnóstico por imagem , Adulto , Corpo Caloso/fisiopatologia , Imagem de Tensor de Difusão , Esotropia/fisiopatologia , Feminino , Humanos , Masculino , Visão Binocular/fisiologia , Acuidade Visual/fisiologia , Córtex Visual/fisiopatologia , Vias Visuais/fisiopatologia
16.
Growth Horm IGF Res ; 37: 19-25, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29107171

RESUMO

Growth hormone deficiency (GHD) can present at any time of life from the neonatal period to adulthood, as a result of congenital or acquired insults. It can present as an isolated problem (IGHD) or in combination with other pituitary hormone deficiencies (CPHD). Pituitary deficits can evolve at any time from GHD diagnosis. The number, severity and timing of occurrence of additional endocrinopathies are highly variable. The risk of progression from IGHD to CPHD in children varies depending on the etiology (idiopathic vs organic). The highest risk is displayed by children with abnormalities in the Hypothalamo-Pituitary (H-P) region. Heterogeneous data have been reported on the type and timing of onset of additional pituitary hormone deficits, with TSH deficiency being most frequent and Diabetes Insipidus the least frequent additional deficit in the majority, but not all, of the studies. ACTH deficiency may gradually evolve at any time during follow-up in children or adults with childhood onset IGHD, particularly (but not only) in presence of H-P abnormalities and/or TSH deficiency. Hence there is a need in these patients for lifelong monitoring for ACTH deficiency. GH treatment unmasks central hypothyroidism mainly in patients with organic GHD, but all patients starting GH should have their thyroid function monitored closely. Main risk factors for development of CPHD include organic etiology, H-P abnormalities (in particular pituitary stalk abnormalities, empty sella and ectopic posterior pituitary), midline brain (corpus callosum) and optic nerves abnormalities, genetic defects and longer duration of follow-up. The current available evidence supports longstanding recommendations for the need, in all patients diagnosed with IGHD, of a careful and indefinite follow-up for additional pituitary hormone deficiencies.


Assuntos
Insuficiência Adrenal/sangue , Hormônio do Crescimento Humano/deficiência , Hipopituitarismo/sangue , Hipopituitarismo/fisiopatologia , Adolescente , Adulto , Criança , Pré-Escolar , Corpo Caloso/fisiopatologia , Progressão da Doença , Feminino , Seguimentos , Humanos , Masculino , Fenótipo , Hipófise/fisiopatologia , Fatores de Risco , Adulto Jovem
17.
Am J Med Genet C Semin Med Genet ; 175(3): 362-367, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28834083

RESUMO

Prader-Willi Syndrome (PWS) is a genetic disorder characterized by infantile hypotonia, hyperphagia, hypogonadism, growth hormone deficiency, intellectual disability, and severe emotional and behavioral problems. The brain mechanisms that underpin these disturbances are unknown. Diffusion tensor imaging (DTI) enables in vivo investigation of the microstructural integrity of white matter pathways. To date, only one study has used DTI to examine white matter alterations in PWS. However, that study used selected regions of interest, rather than a whole brain analysis. In the present study, we used diffusion tensor and magnetic resonance (T 1-weighted) imaging to examine microstructural white matter changes in 15 individuals with PWS (17-30 years) and 15 age-and-gender-matched controls. Whole-brain voxel-wise statistical analysis of FA was carried out using tract-based spatial statistics (TBSS). Significantly decreased fractional anisotropy was found localized to the left hemisphere in individuals with PWS within the splenium of the corpus callosum, the internal capsule including the posterior thalamic radiation and the inferior frontal occipital fasciculus (IFOF). Reduced integrity of these white matter pathways in individuals with PWS may relate to orientating attention, emotion recognition, semantic processing, and sensorimotor dysfunction.


Assuntos
Corpo Caloso/fisiopatologia , Imagem de Tensor de Difusão , Síndrome de Prader-Willi/fisiopatologia , Substância Branca/fisiopatologia , Adolescente , Adulto , Anisotropia , Corpo Caloso/diagnóstico por imagem , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Síndrome de Prader-Willi/diagnóstico por imagem , Síndrome de Prader-Willi/genética , Substância Branca/diagnóstico por imagem , Adulto Jovem
18.
BMC Anesthesiol ; 17(1): 105, 2017 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-28806918

RESUMO

BACKGROUND: To investigate the effect of systemic lipopolysaccharide (LPS) on function of hippocampus and corpus callosum (CC) in adult rats. METHODS: Adult rats with mature white matter tract were divided into systemic LPS and saline injection groups. Animal were euthanized following 3 daily injections (day 3) and 3-day after cessation of injections (day 6). At both time points, hippocampal long term potentiation (LTP) and CC compound action potentials (CAP) were recorded, beta amyloid precursor protein (ß-APP) level in CC tissue was measured by Western blot, and microglia activation was examined by immunostaining and proportional area analysis. RESULTS: Systemic LPS significantly decreased amplitude of both post tetanic potentiation (PTP) and LTP at day 3, but PTP and LTP turned to be normal at day 6. CAP was significantly declined at day 3 but was further declined at day 6. The ß-APP levels in CC tissues of LPS injected rats were significantly higher than that of saline group at both time-points. Interestingly, proportional area measurement disclosed that microglial areas in both hippocampus and CC significantly expanded at day3, but at the day 6, microglial area decreased in hippocampus but further increased in CC. CONCLUSION: Systemic LPS resulted in a transient hippocampus malfunction but a prolonged CC injury. Microglia activation may correlate with such LPS induced white matter injury.


Assuntos
Corpo Caloso/efeitos dos fármacos , Corpo Caloso/lesões , Hipocampo/efeitos dos fármacos , Hipocampo/fisiopatologia , Lipopolissacarídeos/efeitos adversos , Potenciação de Longa Duração/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Corpo Caloso/metabolismo , Corpo Caloso/fisiopatologia , Injeções Intraperitoneais , Lipopolissacarídeos/administração & dosagem , Masculino , Microglia/efeitos dos fármacos , Ratos , Fatores de Tempo
19.
Dev Med Child Neurol ; 59(10): 1042-1048, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28815625

RESUMO

AIM: The objective of this study was to investigate the involvement of the motor fibres of the corpus callosum after unilateral neonatal arterial ischemic stroke (NAIS) of the middle cerebral artery territory and the relationship to both ipsilesional and contralesional hand function. METHOD: Using high-resolution structural magnetic resonance imaging (MRI), functional MRI, and magnetic resonance diffusion-tractography, we compared the midsagittal area of the motor part of the corpus callosum (defined by the fibres connecting the precentral gyri) between 33 7-year-old children after unilateral NAIS and 31 typically developing 7-year-old children. Hand motor performance was assessed by the box and blocks test. RESULTS: Children after NAIS showed on average significantly smaller motor corpus callosum area compared to typically developing children (p<0.001, without differences of the non-motor corpus callosum area). In addition, there was a significant positive association between the motor part of the corpus callosum and both contralesional (Pr(>|t|)=0.034) and ipsilesional hand motor performance (Pr(>|t|)=0.006) after controlling for lesion volume and sex. In a post-hoc analysis the additional contribution of corticospinal tract damage was evaluated. INTERPRETATION: Compared to typically developing children, children after NAIS exhibited a smaller motor part of their corpus callosum associated with reduced contralesional but also ipsilesional manual dexterity. These results indicate that the affection of transcallosal motor fibres in unilateral NAIS might be of functional relevance and an important part of the involved structural network that should be elucidated in further studies.


Assuntos
Isquemia Encefálica/fisiopatologia , Corpo Caloso/fisiopatologia , Mãos/fisiopatologia , Atividade Motora/fisiologia , Acidente Vascular Cerebral/fisiopatologia , Isquemia Encefálica/diagnóstico por imagem , Criança , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/crescimento & desenvolvimento , Imagem de Tensor de Difusão , Feminino , Lateralidade Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Córtex Motor/diagnóstico por imagem , Córtex Motor/fisiopatologia , Tamanho do Órgão , Tratos Piramidais/diagnóstico por imagem , Tratos Piramidais/fisiopatologia , Acidente Vascular Cerebral/diagnóstico por imagem
20.
Neuroreport ; 28(14): 865-871, 2017 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-28737583

RESUMO

Mild traumatic brain injury (mTBI) often results in working memory (WM) impairment, but the mechanistic relationship between the two remains elusive. We used a computational model of two cortical neuronal networks linked by myelinated callosal axons with distance-dependent conduction delays to simulate callosal dysfunction in mTBI and quantify its impact on WM. WM maintenance and termination in the model network depended on short-term synaptic plasticity. In injured networks, WM duration depended on the extent of callosal injury, consistent with clinical data. The model provides a framework for studying callosal injury-induced neurobehavioral alterations following mTBI, and, to the best of our knowledge, is the first computational model to address mTBI-induced WM impairment.


Assuntos
Simulação por Computador , Corpo Caloso/lesões , Corpo Caloso/fisiopatologia , Transtornos da Memória/fisiopatologia , Memória de Curto Prazo/fisiologia , Modelos Neurológicos , Animais , Humanos , Transtornos da Memória/etiologia , N-Metilaspartato/metabolismo , Inibição Neural/fisiologia , Plasticidade Neuronal/fisiologia , Células Piramidais/fisiologia , Tempo de Reação/fisiologia , Sinapses/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/metabolismo , Ácido gama-Aminobutírico/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA