RESUMO
The psychological, neuropsychological, and neurometabolic effects of the hallucinogenic agent mescaline were investigated in 12 normal men who were volunteers. Mescaline produced an acute psychotic state 3 1/2-4 hr after drug intake, as measured by the Brief Psychiatric Rating Scale (BPRS) and Paranoid Depression Scale (PDS). The Assessment of Altered States of Consciousness (APZ) questionnaire revealed specific effects of mescaline in the visual system. Neuropsychological effects were studied with a face/nonface decision task with known right-hemisphere advantage, in which mescaline induced a decrease of functioning of the right hemisphere. In functional brain imaging using single photon emission computed tomography (SPECT), mescaline produced a "hyperfrontal" pattern with an emphasis on the right hemisphere, which was correlated with mescaline-induced psychotic psychopathology. Our findings question the validity of the concept of hypofrontality as an explanation for schizophrenic symptomatology. The study of psychoactive substances under controlled laboratory conditions has the methodological advantage of intraindividual control, and hence, minimal variability of data.
Assuntos
Córtex Cerebral/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Mescalina/toxicidade , Transtornos Neurocognitivos/fisiopatologia , Testes Neuropsicológicos , Escalas de Graduação Psiquiátrica , Adulto , Atenção/efeitos dos fármacos , Atenção/fisiologia , Mapeamento Encefálico/instrumentação , Córtex Cerebral/fisiopatologia , Aprendizagem por Discriminação/efeitos dos fármacos , Aprendizagem por Discriminação/fisiologia , Dominância Cerebral/efeitos dos fármacos , Dominância Cerebral/fisiologia , Metabolismo Energético/fisiologia , Lobo Frontal/irrigação sanguínea , Humanos , Processamento de Imagem Assistida por Computador/instrumentação , Masculino , Pessoa de Meia-Idade , Transtornos Neurocognitivos/psicologia , Reconhecimento Visual de Modelos/efeitos dos fármacos , Reconhecimento Visual de Modelos/fisiologia , Esquizofrenia/induzido quimicamente , Esquizofrenia/fisiopatologia , Psicologia do Esquizofrênico , Tomografia Computadorizada de Emissão de Fóton Único/instrumentaçãoRESUMO
Spontaneous language of 18 patients suffering from Huntington's disease and 15 dysarthric controls suffering from Friedreich's ataxia were investigated. In addition, language functions in various modalities were assessed with the Aachen Aphasia Test (AAT). The Huntington patients exhibited deficits in the syntactical complexity of spontaneous speech and in the Token Test, confrontation naming, and language comprehension subtests of the AAT, which are interpreted as resulting from their dementia. Errors affecting word access mechanisms and production of syntactical structures as such were not encountered.
Assuntos
Afasia/fisiopatologia , Gânglios da Base/fisiopatologia , Córtex Cerebral/fisiopatologia , Doença de Huntington/fisiopatologia , Adulto , Anomia/fisiopatologia , Transtornos da Articulação/fisiopatologia , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Fonética , Semântica , Medida da Produção da FalaRESUMO
Fifteen patients with Friedreich's ataxia underwent a battery of neuropsychologic tests. All subjects had normal visual acuity. There was no indication that Friedreich's ataxia is a dementing disease. The patients showed an impairment in tests of spatial construction and in one test of conceptual perception. Cerebellar structures may be involved in certain spatial tasks, and a lack of training of action in space, as a result of the disease, may also account for the deficits. The motor and somatosensory impairment could be ruled out as a major cause.