RESUMO
OBJECTIVE: The maturation pattern of the envelope following response (EFR) was described using rats as an experimental model. DESIGN: EFRs were recorded in animals at different postnatal ages (15, 20, 25, 35, and 70 postnatal days) in response to broadband noise (BBN) and tones of 8000 and 4000 Hz modulated in amplitude using a continuous sweep of modulation frequencies. Responses were analysed in the 90-190 Hz modulation frequency (MF) range. STUDY SAMPLE: Forty individuals (eight individuals for each age bracket) were included in the present study. RESULTS: During maturation, the MF at which the maximum amplitude was obtained (BMF, best modulation frequency) shifted to higher values when animals were stimulated with tones. At the same time, the amplitude of the response at the BMF increased. For every group of animals, the amplitude of the response continuously decreased for MFs higher than the BMF. However, less steep decreases of amplitude were obtained as animals became adults. CONCLUSIONS: These results provide normative data regarding the maturation of the EFR in rats. They provide information for the development of predictor models to estimate the temporal resolution of the auditory system during maturation.
Assuntos
Envelhecimento , Vias Auditivas/crescimento & desenvolvimento , Percepção Auditiva , Percepção do Tempo , Estimulação Acústica , Fatores Etários , Animais , Audiometria de Resposta Evocada , Potenciais Evocados Auditivos , Ratos , Ratos Wistar , Processamento de Sinais Assistido por Computador , Fatores de TempoRESUMO
It is well established that schizophrenia is associated with difficulties in recognizing facial emotional expressions, but few studies have reported the presence of this deficit among their unaffected relatives. This study attempts to add new evidence of familial association on an emotional expression processing test. The study evaluated the performance of 93 paranoid schizophrenia patients, 110 first-degree relatives of probands from multiplex schizophrenia families, and 109 nonpsychiatric controls on a facial emotional recognition test using a computer morphing technique to present the dynamic expressions. The task entailed the recognition of a set of facial expressions depicting the six basic emotions presented in 21 successive frames of increasing intensity. The findings indicated that schizophrenia patients were consistently impaired for the recognition of the six basic facial expressions. In contrast, their unaffected relatives showed a selective impairment for the recognition of disgust and fearful expressions. Familial association of selective facial emotional expressions processing deficit may further implicate promising new endophenotypes that can advance the understanding of affective deficits in schizophrenia.