RESUMO
A method is reported to determine the phase and amplitude of sinusoidally modulated event rates, binned into four bins per oscillation, based on data generated at the resonant neutron spin-echo spectrometer RESEDA at FRM-II. The presented algorithm relies on a reconstruction of the unknown parameters. It omits a calculation-intensive fitting procedure and avoids contrast reduction due to averaging effects. It allows the current data acquisition bottleneck at RESEDA to be relaxed by a factor of four and thus increases the potential time resolution of the detector by the same factor. The approach is explained in detail and compared with the established fitting procedures of time series having four and 16 time bins per oscillation. In addition the empirical estimates of the errors of the three methods are presented and compared with each other. The reconstruction is shown to be unbiased, asymptotic and efficient for estimating the phase. Reconstructing the contrast increases the error bars by roughly 10% as compared with fitting 16 time-binned oscillations. Finally, the paper gives heuristic, analytical equations to estimate the error for phase and contrast as a function of their initial values and counting statistics.
RESUMO
Although lithium plays a major role in therapy and prophylaxis of affective psychoses, no direct indication of its neuronal action in humans exists. A lithium-induced strong reduction of foveal dark-adaptation was found in healthy volunteers, and a lithium-induced reduction was also measured in patients with affective psychoses. Dark-adaptation measurements apparently offer the opportunity for in vivo monitoring of lithium's CNS effects in humans and may predict lithium's clinical efficacy.
Assuntos
Transtornos Psicóticos Afetivos/tratamento farmacológico , Adaptação à Escuridão/efeitos dos fármacos , Lítio/farmacologia , Adaptação Ocular/efeitos dos fármacos , Adaptação Ocular/fisiologia , Adulto , Transtornos Psicóticos Afetivos/fisiopatologia , Transtornos Psicóticos Afetivos/psicologia , Adaptação à Escuridão/fisiologia , Fóvea Central/efeitos dos fármacos , Fóvea Central/fisiologia , Humanos , Lítio/uso terapêutico , Transtornos Psicóticos/tratamento farmacológico , Transtornos Psicóticos/fisiopatologiaRESUMO
Measurements of binocular depth inversion using a stereoscopic slide projection with polarized light were performed in healthy volunteers before and after cannabis intake. Since binocular depth inversion represents an illusion occurring in the perception of semantically meaningful objects projected in a 3-D inverted fashion, the hypothesis can be tested that cannabis-induced "psychedelic states" represent a condition in which the human CNS is unable to correct implausible perceptual hypotheses. The data demonstrate a strong cannabis-induced impairment of binocular depth inversion.