Positive thinking reduces heart rate and fear responses to speech-phobic imagery.

30 speech-anxious subjects imagined a phobic speech scene 10 times. The experimental conditions varied according to whether the subjects engaged in positive, neutral, or negative thinking prior to each scene presentation. Heart rate and self-reports of fear were measured during the imagery periods. Positive thinking just before visualization of the phobic images reduced both subjective anxiety about speech and cardiovascular responses.

Effect of monosodium glutamate on retinal vessel development and permeability in rats.

Monosodium glutamate (MSG) administered to neonatal rats on postnatal days 1 to 10 caused a generalized degeneration of the inner retinal layers. MSG administered only on postnatal days 8, 9, 10, and/or 11 caused a retinopathy limited to more peripheral retinal areas corresponding to currently existing regions of immature retinal vessels. Ink-injected retinal vessel studies showed a delay in development of the retinal vessel network but no alterations in vessel patency. Fluorescence microscopic examination of freeze-dried tissues revealed to abnormalities of the blood-retinal barriers to sodium fluorescein. We conclude, as demonstrated by these methods, that MSG retards development of the retinal vessels but does not affect development of the blood-retinal barriers. The retinotoxic effect of MSG apparently results from a mechanism(s) other than a breakdown of the blood-retinal barrier.