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1.
Rev Neurol (Paris) ; 168(10): 762-70, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22981269

RESUMO

The most common clinical sign of autism spectrum disorders (ASD) is social interaction impairment, which is associated with communication deficits and stereotyped behaviors. Based on brain-imaging results, our hypothesis is that abnormalities in the superior temporal sulcus (STS) are highly implicated in ASD. These abnormalities are characterized by decreased grey matter concentration, rest hypoperfusion and abnormal activation during social tasks. STS anatomofunctional anomalies occurring early across brain development could constitute the first step in the cascade of neural dysfunctions underlying autism. It is known that STS is highly implicated on social perception processing, from perception of biological movements, such as body movements or eye gaze, to more complex social cognition processes. Among the impairments that can be described in social perception processing, eye gaze perception is particularly relevant in autism. Gaze abnormalities can now be objectively measured using eye-tracking methodology. In the present work, we will review recent data on STS contributions to normal social cognition and its implication in autism, with particular focus on eye gaze perception.


Assuntos
Transtorno Autístico/fisiopatologia , Cognição/fisiologia , Percepção Social , Lobo Temporal/fisiologia , Transtorno Autístico/diagnóstico por imagem , Movimentos Oculares/fisiologia , Humanos , Imageamento por Ressonância Magnética , Tomografia por Emissão de Pósitrons , Radiografia , Comportamento Social , Lobo Temporal/fisiopatologia
2.
J Neuroradiol ; 37(4): 220-30, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20378176

RESUMO

OBJECTIFS: To propose a MRI cerebellar algorithm that may be applied to guide genetic/malformative or biochemical investigations for patients with cerebellar ataxia. PATIENTS AND METHODS: Cerebral MRI of 158 patients with cerebellar ataxia and no supratentorial abnormality were examined according to a new categorization system based on posterior fossa imaging. The clinical and radiological findings were confronted to biochemical and/or genetic results using the MR cerebellar algorithm. Seven groups of cerebellar MRI pattern were described: vermian dysgenesis (n=27), cerebellar hypoplasia (n=15), hemispheric cerebellar dysgenesis (n=6), unilateral hemispheric atrophy (n=5), global cerebellar atrophy (n=84), signal abnormalities (n=11) and normal MRI (n=10). Cerebellar hypoplasia, vermian dysgenesis and hemispheric cerebellar dysgenesis groups were classified as malformative disorders. Global atrophy and signal abnormality groups were classified as metabolic disorders. RESULTS: In the vermian dysgenesis group, a specific genetic diagnosis was obtained in eight children (8/27) and all of the mutated genes (AHI1 (JBS3), CEP290 (JBS5), TMEM67 (JBS6), and RPGRIP1L (JBS7)) are involved in primary cilia function. In the group of pontocerebellar hypoplasia specific genetic diagnosis was obtained in one patient (PCH2) (1/15). Thus, nine of 42 children classified as malformative disorder had a molecular diagnosis. Global atrophy and signal abnormality groups were classified as metabolic disorders, specific biochemical was obtained in 46/95 children. In global atrophy group, respiratory chain deficiency was diagnosed in 18 children (18/84). In 21 children a congenital disorders of glycosylation type 1a (CDG Ia) was diagnosed (21/84) and infantile neuroaxonale dystrophy (INAD) was diagnosed in one child. In signal abnormalities group, specific biochemical diagnosis was obtained in six out of 11 children, five children with respiratory chain deficiency and one child with sulphite oxidase deficiency. In hemispheric cerebellar dysgenesis and normal MRI groups, no biological diagnosis was found for any of the patients. In the group of unilateral hemispheric atrophy, we hypothesized a clastic prenatal injury. CONCLUSION: The proposed MR cerebellar algorithm was useful to guide genetic/malformative or biochemical investigations, allowing an etiological diagnosis in 55 children.


Assuntos
Ataxia Cerebelar/patologia , Cerebelo/patologia , Fossa Craniana Posterior/patologia , Adolescente , Algoritmos , Cerebelo/anormalidades , Criança , Pré-Escolar , Fossa Craniana Posterior/anormalidades , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Seleção de Pacientes
3.
Sci Rep ; 10(1): 6379, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32286406

RESUMO

Humans show great interindividual variability in the degree they engage in social relationship. The neural basis of this variability is still poorly understood, particularly in children. In this study, we aimed to investigate the neural basis of interindividual variability in the first step of social behavior, that is social perception, in typically developing children. For that purpose, we first used eye-tracking to objectively measure eye-gaze processing during passive visualization of social movie clips in 24 children and adolescents (10.5 ± 2.9 y). Secondly, we correlated eye-tracking data with measures of fractional anisotropy, an index of white matter microstructure, obtained using diffusion tensor imaging MRI. The results showed a large interindividual variability in the number of fixations to the eyes of characters during visualization of social scenes. In addition, whole-brain analysis showed a significant positive correlation between FA and number of fixations to the eyes,mainly in the temporal part of the superior longitudinal fasciculi bilaterally, adjacent to the posterior superior temporal cortex. Our results indicate the existence of a neural signature associated with the interindividual variability in social perception in children, contributing for better understanding the neural basis of typical and atypical development of a broader social expertise.


Assuntos
Córtex Cerebral/fisiologia , Rede Nervosa/fisiologia , Percepção Social , Substância Branca/fisiologia , Adolescente , Criança , Imagem de Tensor de Difusão , Feminino , Fixação Ocular , Humanos , Masculino
4.
Transl Psychiatry ; 7(8): e1197, 2017 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-28786975

RESUMO

Mastocytosis is a rare disease in which chronic symptoms are related to mast cell accumulation and activation. Patients can display depression-anxiety-like symptoms and cognitive impairment. The pathophysiology of these symptoms may be associated with tissular mast cell infiltration, mast cell mediator release or both. The objective of this study is to perform morphological or functional brain analyses in mastocytosis to identify brain changes associated with this mast cell disorder. We performed a prospective and monocentric comparative study to evaluate the link between subjective psycho-cognitive complaints, psychiatric evaluation and objective medical data using magnetic resonance imaging with morphological and perfusion sequences (arterial spin-labeled perfusion) in 39 patients with mastocytosis compared with 33 healthy controls. In the test cohort of 39 mastocytosis patients with psycho-cognitive complaints, we found that 49% of them had morphological brain abnormalities, mainly abnormal punctuated white matter abnormalities (WMA). WMA were equally frequent in cutaneous mastocytosis patients and indolent forms of systemic mastocytosis patients (42% and 41% of patients with WMA, respectively). Patients with WMA showed increased perfusion in the putamen compared with patients without WMA and with healthy controls. Putamen perfusion was also negatively correlated with depression subscores. This study demonstrates, for we believe the first time, a high prevalence of morphological and functional abnormalities in the brains of mastocytosis patients with neuropsychiatric complaints. Further studies are required to determine the mechanism underpinning this association and to ascertain its specificity.


Assuntos
Encéfalo/diagnóstico por imagem , Mastocitose/diagnóstico por imagem , Neuroimagem , Substância Branca/diagnóstico por imagem , Adolescente , Adulto , Idoso , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Marcadores de Spin , Adulto Jovem
5.
Am J Psychiatry ; 152(2): 248-52, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7840359

RESUMO

OBJECTIVE: The authors investigated the metabolic maturation of the frontal cortex in pre-school autistic children. METHOD: Regional cerebral blood flow (CBF) in five children with primary autism diagnosed according to the DSM-III-R criteria was studied longitudinally. Regional CBF in each of the autistic children was measured with single photon emission computed tomography twice during their development: at the age of 3-4 years and 3 years later. At each stage, the autistic children were compared to an age-matched comparison group of five nonautistic children with normal development. RESULTS: A transient frontal hypoperfusion was found in the autistic children at ages 3-4 years; this corresponded to the pattern of perfusion observed in much younger normal children. By the ages of 6-7, the autistic children's frontal perfusion had attained normal values. CONCLUSIONS: Since CBF patterns in children are related to maturational changes in brain function, these results indicate a delayed frontal maturation in childhood autism. Such a delayed brain maturational process is consistent with the clinical data and cognitive performance of autistic children.


Assuntos
Transtorno Autístico/fisiopatologia , Circulação Cerebrovascular , Desenvolvimento Infantil/fisiologia , Lobo Frontal/fisiopatologia , Adolescente , Transtorno Autístico/diagnóstico por imagem , Transtorno Autístico/metabolismo , Criança , Pré-Escolar , Feminino , Lobo Frontal/crescimento & desenvolvimento , Lobo Frontal/metabolismo , Humanos , Estudos Longitudinais , Masculino , Tomografia Computadorizada de Emissão , Tomografia Computadorizada de Emissão de Fóton Único
6.
Am J Psychiatry ; 149(7): 924-30, 1992 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1609873

RESUMO

OBJECTIVE: The authors investigated a possible cortical brain dysfunction associated with infantile autism. METHOD: They measured regional cerebral blood flow with single photon emission computed tomography (SPECT) and xenon-133 in 21 children with primary autism (according to DSM-III-R criteria). Five cortical brain areas including frontal, temporal, and sensory association cortices were examined in order to test the recent hypothesis of cerebral dysfunction in primary autism. Anatomical references for each subject were obtained with computerized tomography or magnetic resonance imaging and were used to delimit the regions of interest for SPECT analysis. RESULTS: When the results from the group with primary autism were compared with an age-matched group of nonautistic children with slight to moderate language disorders (N = 14), no cortical regional abnormalities were found. CONCLUSIONS: It appears that there is no regional cortical dysfunction in primary autism; however, in light of methodological limitations, one cannot exclude the possibility of more localized or subcortical brain dysfunctions in autism.


Assuntos
Transtorno Autístico/diagnóstico por imagem , Córtex Cerebral/irrigação sanguínea , Circulação Cerebrovascular , Tomografia Computadorizada de Emissão de Fóton Único , Transtorno Autístico/diagnóstico , Criança , Pré-Escolar , Diagnóstico Diferencial , Feminino , Humanos , Transtornos da Linguagem/diagnóstico , Transtornos da Linguagem/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Tomografia Computadorizada por Raios X , Radioisótopos de Xenônio
7.
Am J Psychiatry ; 157(12): 1988-93, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11097965

RESUMO

OBJECTIVE: The nature of the underlying brain dysfunction of childhood autism, a life-long severe developmental disorder, is not well understood. Although researchers using functional brain imaging have attempted to contribute to this debate, previous studies have failed to report consistent localized neocortical brain dysfunction. The authors reasoned that early methods may have been insensitive to such dysfunction, which may now be detectable with improved technology. METHOD: To test this hypothesis, regional cerebral blood flow was measured with positron emission tomography (PET) in 21 children with primary autism and in 10 nonautistic children with idiopathic mental retardation. Autistic and comparison groups were similar in average age and developmental quotients. The authors first searched for focal brain dysfunction in the autistic group by using a voxel-based whole brain analysis and then assessed the sensitivity of the method to detect the abnormality in individual children. An extension study was then performed in an additional group of 12 autistic children. RESULTS: The first autistic group had a highly significant hypoperfusion in both temporal lobes centered in associative auditory and adjacent multimodal cortex, which was detected in 76% of autistic children. Virtually identical results were found in the second autistic group in the extension study. CONCLUSIONS: PET and voxel-based image analysis revealed a localized dysfunction of the temporal lobes in school-aged children with idiopathic autism. Further studies will clarify the relationships between these temporal abnormalities and the perceptive, cognitive, and emotional developmental abnormalities characteristic of this disorder.


Assuntos
Transtorno Autístico/diagnóstico por imagem , Transtorno Autístico/fisiopatologia , Lobo Temporal/irrigação sanguínea , Lobo Temporal/diagnóstico por imagem , Tomografia Computadorizada de Emissão , Adolescente , Transtorno Autístico/diagnóstico , Criança , Diagnóstico Diferencial , Feminino , Lateralidade Funcional/fisiologia , Humanos , Interpretação de Imagem Assistida por Computador , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/diagnóstico por imagem , Deficiência Intelectual/fisiopatologia , Masculino , Fluxo Sanguíneo Regional , Lobo Temporal/fisiopatologia , Tomografia Computadorizada de Emissão/estatística & dados numéricos
8.
Neurology ; 47(6): 1504-11, 1996 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8960735

RESUMO

We examined mechanisms of recovery from aphasia in seven nonfluent aphasic patients, who were successfully treated with melodic intonation therapy (MIT) after a lengthy absence of spontaneous recovery. We measured changes in relative cerebral blood flow (CBF) with positron emission tomography (PET) during hearing and repetition of simple words, and during repetition of MIT-loaded words. Without MIT, language tasks abnormally activated right hemisphere regions, homotopic to those activated in the normal subject, and deactivated left hemisphere language zones. In contrast, repeating words with MIT reactivated Broca's area and the left prefrontal cortex, while deactivating the counterpart of Wernicke's area in the right hemisphere. The recovery process induced by MIT in these patients probably coincides with this reactivation of left prefrontal structures. In contrast, the right hemisphere regions abnormally activated during simple language tasks seem to be associated with the initial persistence of the aphasia. This study supports the idea that abnormal activation patterns in the lesioned brain are not necessarily related to the recovery process.


Assuntos
Afasia/diagnóstico por imagem , Afasia/terapia , Musicoterapia , Adulto , Encéfalo/diagnóstico por imagem , Humanos , Pessoa de Meia-Idade , Tomografia Computadorizada de Emissão
9.
Neurology ; 52(3): 571-7, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10025790

RESUMO

OBJECTIVE: To investigate whether tactile extinction alters the cortical somatosensory activations induced by hand vibration. BACKGROUND: Tactile extinction occurs mainly after right-brain lesions and consists of the inability to perceive a contralesional cutaneous stimulation when a similar stimulus is applied to the mirror region of the ipsilesional hemibody. The pathophysiology of tactile extinction is poorly understood, but it is considered to be a deficit of selective attention of somatosensory stimuli. Although other theories have been proposed, our understanding of the pathophysiology of tactile extinction may benefit from functional imaging studies. METHODS: We selected three patients with pure tactile extinction and a mainly subcortical right-brain lesion that spared the primary sensorimotor cortex (SM1). We used PET to investigate the responses to unilateral and bilateral hand vibration in SM1 and the secondary somatosensory cortical area (SII). RESULTS: During bilateral hand vibration, activation was normal in the left SM1, suppressed in the right SM1, and markedly decreased in both SII, which was consistent with the extinction of the left-hand stimulus. During unilateral left-hand vibration, the activation of the right SM1 was still markedly impaired, but the activation of both SII was normal. CONCLUSIONS: We found marked changes in the activation of cortical somatosensory areas induced by hand vibration in patients with tactile extinction. The role of selective attention in cortical activation is also examined.


Assuntos
Extinção Psicológica/fisiologia , Córtex Somatossensorial/diagnóstico por imagem , Córtex Somatossensorial/fisiologia , Tato , Idoso , Mapeamento Encefálico , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada de Emissão
10.
Neuropsychologia ; 30(6): 565-80, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1641120

RESUMO

Using regional cerebral blood flow (rCBF) imaging, two populations having high and low imagery abilities were compared at rest and while performing two cognitive tasks: silent verb conjugation and mental imagery. The imagery task produced an rCBF increase in the left visual association and left frontal cortices in both groups. Differences between high and low imagers were observed on global and regional flow responses to cognitive tasks: low imagers showed a whole cortex CBF increase during both tasks; high imagers showed a right dominance in the visual association cortex in all conditions, and in the parietal association cortex at rest.


Assuntos
Aptidão/fisiologia , Nível de Alerta/fisiologia , Encéfalo/irrigação sanguínea , Imaginação/fisiologia , Tomografia Computadorizada de Emissão de Fóton Único , Comportamento Verbal/fisiologia , Adulto , Mapeamento Encefálico , Córtex Cerebral/irrigação sanguínea , Dominância Cerebral/fisiologia , Feminino , Humanos , Masculino , Valores de Referência , Fluxo Sanguíneo Regional/fisiologia
11.
J Nucl Med ; 33(5): 696-703, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-1569478

RESUMO

Regional cerebral blood flow (rCBF) was studied by SPECT using 133Xe in 42 children, aged 2 days to 19 years, considered as neurologically normal. rCBF was measured on cortical regions and on the cerebellum and thalamus. Curves for reference values and standard deviation were defined for each region. At birth, cortical rCBFs were lower than those for adults; after birth they increased until 5 or 6 yr of age to values 50%-85% higher than those for adults and thereafter decreased, reaching adult levels between 15 and 19 yr. Neonatal values of rCBF on cerebellum and thalamus were slightly higher than adult level, but not significantly; after age 1, they followed the common pattern for cortical curves. When rCBFs were expressed in percent global CBF, they were lower at birth than adult levels in the cortex, then increased and reached a plateau corresponding to the adult value before the second year of age. The time needed to reach normal adult values differed for each cortical region. The shortest time was found on the primary cortex and the longest on the associative cortex. Cognitive development of the child seems to be related to changes in blood flow of the corresponding brain regions.


Assuntos
Encéfalo/diagnóstico por imagem , Circulação Cerebrovascular/fisiologia , Tomografia Computadorizada de Emissão de Fóton Único , Adolescente , Encéfalo/crescimento & desenvolvimento , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Valores de Referência , Radioisótopos de Xenônio
12.
J Nucl Med ; 37(12): 1976-81, 1996 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8970517

RESUMO

UNLABELLED: Fluorine-18-setoperone PET imaging was used to investigate serotonergic 5-HT2-specific binding in unlesioned cerebral cortex in stroke patients. METHODS: Seventeen stroke patients (mean age 50 +/- 31 yr) with right (n = 9) or left (n = 8) chronic stroke (middle or anterior cerebral artery territory) underwent [18F]setoperone PET and MR imaging. The distribution volume of the 5-HT2-specific binding at equilibrium (DVSe) was determined in the unlesioned cortical regions. The results were compared with those obtained in 14 age-matched controls. In addition, we investigated the effect of the side of the stroke, lesion volume and its localization. RESULTS: After removing the age effect by covariance analysis, we found a significant DVSe decrease in the temporal (p < 0.05) and frontal (p < 0.05) unlesioned cortices ipsilateral to the stroke. The changes were similar in patients with left and right stroke and did not correlate with the volume of the stroke. However, the localization of the stroke affected the topography of DVSe abnormalities. When the lesion did not extend more medially than the internal capsule, DVSe was significantly reduced in the temporal lobe (-30%, p < 0.05) but not in the frontal lobe (-21%, p = ns). Conversely, when the lesion extended subcortically in the anteromedial region, close to the midline, DVSe was reduced in both temporal (-40%, p < 0.05) and frontal (- 49%, p < 0.05) lobes. CONCLUSION: This study confirms that stroke may alter 5-HT2 receptors in large unlesioned cortical areas and that the changes depend on the subcortical extent of the lesion.


Assuntos
Córtex Cerebral/metabolismo , Transtornos Cerebrovasculares/metabolismo , Receptores de Serotonina/metabolismo , Tomografia Computadorizada de Emissão , Adulto , Fatores Etários , Idoso , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/patologia , Transtornos Cerebrovasculares/diagnóstico , Transtornos Cerebrovasculares/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Pirimidinonas
13.
J Nucl Med ; 33(8): 1481-5, 1992 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-1386104

RESUMO

We assessed the potential use of [123I]iodolisuride (ILIS), a new iodine ergolene derivative, to study human striatal D2 dopamine receptors with SPECT. In normal subjects, we found that the tracer accumulated preferentially in striatum. This was prevented by high doses of haloperidol. The striatal accumulation was maximal between 60 and 180 min after injection. The striatum-to-cerebellum radioactivity concentration ratio as an index of specific binding, measured 60 min after injection, was 1.52 +/- 0.19 (mean +/- s.d.) in controls and 1.36 +/- 0.11 in patients with supranuclear palsy (p less than 0.03). Our results show that ILIS may be used to study D2 receptors with SPECT. In-vivo changes of D2 receptors in human brain may be detected with this method.


Assuntos
Cerebelo/diagnóstico por imagem , Corpo Estriado/diagnóstico por imagem , Lisurida/análogos & derivados , Receptores Dopaminérgicos/metabolismo , Paralisia Supranuclear Progressiva/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único , Adulto , Idoso , Biomarcadores , Cerebelo/metabolismo , Corpo Estriado/metabolismo , Humanos , Radioisótopos do Iodo , Pessoa de Meia-Idade , Receptores de Dopamina D2 , Valores de Referência
14.
Neuroreport ; 11(13): 2969-72, 2000 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-11006976

RESUMO

The functional architecture of human auditory cortex is still poorly understood compared with that of visual cortex, yet anatomical and electrophysiological studies in non-human primates suggest that the auditory cortex also might be functionally specialized, in a model of parallel and hierarchical organization. In particular, spectral changes such as the formant transitions of speech, or spectral motion (SM) by analogy with visual motion, could be processed in specialized cortical regions. In this study, positron emission tomography (PET) was used to identify which auditory cortical region are involved in SM analysis. We found that a bilateral secondary auditory cortical region, located in the caudal-lateral belt of auditory cortex, was more sensitive to auditory stimuli containing spectral changes than to matched stimuli with a stationary spectral profile. This result suggests that analogies between sensory systems could prove useful in the research into the functional organization of the auditory cortex.


Assuntos
Córtex Auditivo/diagnóstico por imagem , Percepção Auditiva/fisiologia , Estimulação Acústica , Adolescente , Adulto , Córtex Auditivo/fisiologia , Circulação Cerebrovascular/fisiologia , Lateralidade Funcional/fisiologia , Humanos , Masculino , Tálamo/diagnóstico por imagem , Tálamo/fisiologia , Tomografia Computadorizada de Emissão
15.
Epilepsy Res ; 8(3): 232-40, 1991 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1907910

RESUMO

Hemimegalencephaly (HME) is a severe unilateral brain malformation the prognosis of which may be improved by hemispherectomy. HME also provides a unique opportunity to compare normal and pathological hemispheric function in the same patient. We performed a serial functional cerebral imaging study in a child suffering from a neuropathologically confirmed left HME. He was hemispherectomized at 11 months because of intractable epilepsy; this led to cessation of seizures and dramatic psychomotor improvement. Regional cerebral blood flow (rCBF) was studied at 1, 7, 10, 12 and 25 months with single photon computed tomography (SPECT) using 133-Xenon and with simultaneous EEG recording. At one month of age SPECT was performed ictally. During left EEG discharges, rCBF was 40% higher on the left hemisphere than on the right, even in occipital and frontal regions, usually immature at this age. A crossed cerebellar hyperperfusion was also found. At 7 and 10 months, SPECT was performed interictally; rCBF was 45% lower in the left hemisphere than in the right. During follow-up, global and regional CBF values showed normal levels and normal maturation in the right hemisphere except for a mild and transient decrease observed one month after hemispherectomy. SPECT provides an additional procedure for studying hemispheric function in vivo. Serial SPECT imaging may be useful for the preoperative and postoperative evaluation in unilateral cerebral malformation.


Assuntos
Encéfalo/cirurgia , Circulação Cerebrovascular , Epilepsias Parciais/etiologia , Encéfalo/anormalidades , Encéfalo/diagnóstico por imagem , Cerebelo/diagnóstico por imagem , Cerebelo/fisiopatologia , Eletroencefalografia , Epilepsias Parciais/diagnóstico por imagem , Epilepsias Parciais/fisiopatologia , Epilepsias Parciais/cirurgia , Humanos , Recém-Nascido , Masculino , Tomografia Computadorizada de Emissão de Fóton Único
16.
IEEE Trans Med Imaging ; 22(6): 754-65, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12872951

RESUMO

In this paper, we propose a new representation of the cortical surface that may be used to study the cortex folding process and to recover some putative stable anatomical landmarks called sulcal roots usually buried in the depth of adult brains. This representation is a primal sketch derived from a scale space computed for the mean curvature of the cortical surface. This scale-space stems from a diffusion equation geodesic to the cortical surface. The primal sketch is made up of objects defined from mean curvature minima and saddle points. The resulting sketch aims first at highlighting significant elementary cortical folds, second at representing the fold merging process during brain growth. The relevance of the framework is illustrated by the study of central sulcus sulcal roots from antenatal to adult age. Some results are proposed for ten different brains. Some preliminary results are also provided for superior temporal sulcus.


Assuntos
Algoritmos , Córtex Cerebral/anatomia & histologia , Córtex Cerebral/crescimento & desenvolvimento , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Morfogênese/fisiologia , Técnica de Subtração , Adulto , Criança , Humanos , Lactente , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
Pediatr Neurol ; 10(1): 20-6, 1994 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7515240

RESUMO

This study used xenon 133 inhalation and single-photon computed tomography to measure regional cerebral blood flow during a quiet resting condition, a simple auditory task, and an auditory phonemic discrimination task in 3 age-matched groups of children suffering from developmental language disabilities: expressive dysphasia, expressive-receptive dysphasia, and attention-deficit hyperactivity disorder. An absence of left hemisphere activation was observed in the expressive-receptive group during the phonemic discrimination task as compared to both expressive and attention-deficit hyperactivity disorder children, together with an absence of left inferior parietal region activation in dysphasics as compared to hyperactive children. These results favor the hypothesis of an abnormal lateralization for language in dysphasic children and point toward possible different pathologic localizations in the different clinical subtypes of dysphasia.


Assuntos
Afasia/diagnóstico por imagem , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico por imagem , Córtex Cerebral/irrigação sanguínea , Dominância Cerebral/fisiologia , Transtornos do Desenvolvimento da Linguagem/diagnóstico por imagem , Afasia/fisiopatologia , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Mapeamento Encefálico , Criança , Feminino , Humanos , Transtornos do Desenvolvimento da Linguagem/fisiopatologia , Masculino , Fluxo Sanguíneo Regional/fisiologia , Percepção da Fala/fisiologia , Tomografia Computadorizada de Emissão de Fóton Único , Radioisótopos de Xenônio
18.
Pediatr Neurol ; 25(2): 170-4, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11551749

RESUMO

Hallervorden-Spatz syndrome is a group of rare and severe disorders marked by extrapyramidal symptoms and iron accumulation in the globi pallidi, usually visible by magnetic resonance imaging. To assist in determining the functional correlates of these structural abnormalities, positron emission tomography was used to measure regional cerebral blood flows and dopaminergic function in a patient with Hallervorden-Spatz syndrome that manifested as progressive generalized dystonia, optic atrophy, and bilateral pallidal "eye of the tiger" sign. Voxel-by-voxel analysis of positron emission tomography images revealed no pallidal abnormalities but demonstrated significant hypoperfusion of the head of the right caudate nucleus, pons, and cerebellar vermis. Dopaminergic function of the basal ganglia, which was assessed based on visual- analysis of fixation of 18F-labeled fluoro-levodopa, was normal. These data suggest that Hallervorden-Spatz syndrome pathogenesis is not confined to the globi pallidi, and these data also may help to generate new pathogenic hypothesis.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Circulação Cerebrovascular/fisiologia , Neurodegeneração Associada a Pantotenato-Quinase/diagnóstico por imagem , Neurodegeneração Associada a Pantotenato-Quinase/patologia , Encéfalo/fisiopatologia , Criança , Dopamina/fisiologia , Humanos , Masculino , Neurodegeneração Associada a Pantotenato-Quinase/fisiopatologia , Tomografia Computadorizada de Emissão
19.
Rev Neurol (Paris) ; 157(8-9 Pt 1): 837-46, 2001 Sep.
Artigo em Francês | MEDLINE | ID: mdl-11677406

RESUMO

Since the description of cortical deafness, it has been known that the superior temporal cortex is bilaterally involved in the initial stages of language auditory perception but the precise anatomical limits and the function of this area remain debated. Here we reviewed more than 40 recent papers of positron emission tomography and functional magnetic resonance imaging related to language auditory perception, and we performed a meta-analysis of the localization of the peaks of activation in the Talairach's space. We found 8 studies reporting word versus non-word listening contrasts with 54 activation peaks in the temporal lobes. These peaks clustered in a bilateral and well-limited area of the temporal superior cortex, which is here operationally defined as the speech sensitive auditory cortex. This area is more than 4cm long, located in the superior temporal gyrus and the superior temporal sulcus, both anterior and posterior to Heschl's gyrus. It do not include the primary auditory cortex nor the ascending part of the planum temporale. The speech sensitive auditory cortex is not activated by pure tones, environmental sounds, or attention directed toward elementary components of a sound such as intensity, pitch, or duration, and thus has some specificity for speech signals. The specificity is not perfect, since we found a number of non-speech auditory stimuli activating the speech sensitive auditory cortex. Yet the latter studies always involve auditory perception mechanisms which are also relevant to speech perception either at the level of primitive auditory scene analysis processes, or at the level of specific schema-based recognition processes. The dorsal part of the speech sensitive auditory cortex may be involved in primitive scene analysis processes, whereas distributed activation of this area may contribute to the emergence of a broad class of "voice" schemas and of more specific "speech schemas/phonetic modules" related to different languages. In addition, this area is activated by language-related lip movement, suggesting that a multimodal integration of the auditory and the visual information relevant in speech perception occurs at this level. Finally, there is a task-related top-down modulation of the pattern of activation of the speech sensitive auditory cortex which may reflect the fact that the different parts of this structure are connected to different down-stream cortical regions involved in the neural processing of different types of tasks.


Assuntos
Córtex Auditivo/fisiologia , Percepção Auditiva/fisiologia , Idioma , Imageamento por Ressonância Magnética , Percepção da Fala/fisiologia , Vias Auditivas/fisiologia , Mapeamento Encefálico , Dominância Cerebral/fisiologia , Humanos , Fonética
20.
Rev Neurol (Paris) ; 155(9): 725-30, 1999.
Artigo em Francês | MEDLINE | ID: mdl-10528357

RESUMO

Aphasia recovery may depend on right hemisphere or non-lesioned left hemisphere structures, pre-morbid brain language organization, and de novo learning of language. Here we review the brain imaging evidence supporting these different hypotheses. CT-scan studies have investigated the prognosis value of size and site of left hemisphere lesions. The size of the lesion is a global but not an individual predictor of the initial severity and subsequent recovery of aphasia. Studies on the site of the lesion have given different results for verbal expression and comprehension. There is no consensus on a single critical site for recovery of verbal expression in non-fluent aphasia, which may depend on sub-cortical more than cortical extend of the lesion. Conversely the extend of the lesion in the superior temporal gyrus emerges as a critical negative factor for comprehension recovery. Rest measurements of brain metabolism have consistently shown that aphasia severity depends much more on the degree of dysfunction of language-related areas in the left hemisphere than on the site of the lesion it-self. This suggests that aphasia recovery may depend on metabolic dysfunction recovery in peri-lesional structures. More recently, activation studies have shown consistent right hemisphere activation during language tasks in aphasic subjects, but their role in recovery remains debated. It is likely limited, and may depend on atypical pre-morbid language lateralization. Left hemisphere activations are also found in aphasic patients. They are often relocalized in peri-lesional areas, and emerge in most studies as the main factor of aphasia recovery.


Assuntos
Afasia/reabilitação , Encéfalo/patologia , Afasia/diagnóstico , Encéfalo/diagnóstico por imagem , Lateralidade Funcional/fisiologia , Humanos , Imageamento por Ressonância Magnética , Magnetoencefalografia , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada por Raios X
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