RESUMO
The human hippocampus is critical to episodic encoding, but the role of the amygdala in memory is less clear. Animal research suggests a role for the amygdala in associative memory, but this has not been examined systematically in humans. Using fMRI, we compared amygdala and hippocampus activation for seven healthy subjects during two visual encoding tasks: serially presented single faces and faces presented as pairs. Single faces activated bilateral hippocampi, but not the amygdala. Paired faces activated bilateral amygdala, but only the left hippocampus. Subtraction of the two conditions revealed greater activation within the left amygdala and hippocampus during paired face encoding, suggesting that associative encoding activates a left-lateralized limbic network including the hippocampus and amygdala.
Assuntos
Tonsila do Cerebelo/fisiologia , Aprendizagem por Associação/fisiologia , Mapeamento Encefálico , Lateralidade Funcional , Hipocampo/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Adulto , Face , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Memória/fisiologia , Especificidade de ÓrgãosRESUMO
The authors report the findings of multimodal structural, functional, and metabolic imaging in a patient with linear nevus sebaceous syndrome, intractable seizures, and right megalencephaly. Despite nearly continuous paroxysmal electrical activity from the megalencephalic region, imaging studies suggested nonfunctional tissue in this region with reorganization of cortical function to the unaffected ipsilateral hemisphere. Hemispherectomy has been successfully performed in previous patients; however, it could have led to marked left hemiparesis with significant functional morbidity in this patient because of ipsilateral reorganization of the primary motor cortex.
Assuntos
Encefalopatias/diagnóstico , Córtex Cerebral/patologia , Diagnóstico por Imagem , Síndromes Neurocutâneas/diagnóstico , Nevo/diagnóstico , Adulto , Encéfalo/anormalidades , Meios de Contraste , Eletroencefalografia , Epilepsia/diagnóstico , Humanos , Aumento da Imagem , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Convulsões/diagnóstico , Tomografia Computadorizada de Emissão , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
Prediction of post-surgical seizure relief and potential cognitive deficits secondary to anterior temporal lobectomy (ATL) are important to pre-surgical planning. Although the intracarotid amobarbital test (IAT) is predictive of post-ATL seizure outcome, development of non-invasive and more precise means for determining post-ATL seizure relief are needed. We previously reported on a technique utilizing functional MRI (fMRI) to evaluate the relative functional adequacy of mesial temporal lobe structures in preparation for ATL. In the present study, we report follow-up outcome data on eight temporal lobe epilepsy (TLE) patients 1-year post-ATL who were evaluated pre-surgically using IAT and fMRI. Functional memory lateralization using fMRI predicted post-ATL seizure outcome as effectively as the IAT. In general, asymmetry of functional mTL activation favouring the non-epileptic hemisphere was associated with seizure-free status at 1-year follow-up. Moreover, when combined, fMRI and IAT provided complementary data that resulted in improved prediction of post-operative seizure control compared with either procedure alone.
Assuntos
Amobarbital , Epilepsia do Lobo Temporal , Moduladores GABAérgicos , Complicações Pós-Operatórias/prevenção & controle , Psicocirurgia/métodos , Lobo Temporal/cirurgia , Adolescente , Adulto , Amobarbital/administração & dosagem , Amobarbital/farmacocinética , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/prevenção & controle , Vias de Administração de Medicamentos , Epilepsia do Lobo Temporal/diagnóstico , Epilepsia do Lobo Temporal/prevenção & controle , Epilepsia do Lobo Temporal/cirurgia , Feminino , Lateralidade Funcional/fisiologia , Moduladores GABAérgicos/administração & dosagem , Moduladores GABAérgicos/farmacocinética , Humanos , Imageamento por Ressonância Magnética , Masculino , Memória/fisiologia , Cuidados Pós-Operatórios , Valor Preditivo dos Testes , Cuidados Pré-OperatóriosRESUMO
Cerebral hemispheric lateralization and personality traits were evaluated in 154 undergraduate and nonclinical volunteers. Personality ratings did not differ significantly between groups defined on the basis of hand, eye, or ear preference.