Dopamine (DA) D1-like receptors are present in pathways implicated in feedback control of midbrain DA neurons. However, stimulation of these receptors either produces no effect on DA cells, or the effect is inconsistent. It is possible that the expression of a D1 feedback effect requires co-activation of D2-like receptors. To test this hypothesis, we recorded extracellularly the spontaneous activity of nigral DA cells in a low cerveau isolé rat preparation. SKF38393 and dyhydrexidine, two D1 agonists, were administered systemically to animals pretreated with different doses of the D2 agonist quinpirole. Supporting the hypothesis, the two D1 agonists consistently inhibited DA cells in animals given high doses of quinpirole (Ն40 g/kg, i.v.). However, no significant D1 effect was observed in animals pretreated with only low doses (Յ20 g/kg) of quinpirole. Because low doses of D2 agonists preferentially act on DA autoreceptors, and because the D1 inhibition persisted in animals whose DA autoreceptors were blocked by intranigral application of raclopride, our results suggest that the expression of D1 feedback inhibition requires co-activation of D2-like receptors on DA target neurons, instead of DA neurons themselves. These results, together with the finding that chloral hydrate completely blocked the D1 inhibition, may explain why previous studies have failed to show a consistent D1 effect on DA cells and suggest that drugs designed to act specifically on one subtype of DA receptor may, via feedback pathways, influence the action of endogenous DA on other DA receptor subtypes as well.

Increasingly, the risk assessment community has recognized the social and cultural aspects of vulnerability to hurricanes and other hazards that impact planning and public communication. How individuals and communities understand and react to natural hazard risk communications can be driven by a number of different cognitive, cultural, economic, and political factors. The social sciences have seen an increased focus over the last decade on studying hurricane understanding and responses from a social, cognitive, or decision science perspective, which, broadly defined, includes a number of disparate fields. This paper is a cross-disciplinary and critical review of those efforts as they are relevant to hurricane risk communication development. We focus on two areas that, on the basis of a comprehensive literature review and discussions with experts in the field, have received comparatively little attention from the hazards community: 1) research concerning visual communications and the way in which individuals process, understand, and make decisions regarding them and 2) the way in which vulnerable communities understand and interact with hurricane warning communications. We go on to suggest areas that merit increased research and draw lessons or guidance from the broader hazards/social science research realm that has implications for hurricane planning and risk communication, particularly the development and dissemination of hurricane forecast products.

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Audiological use of the 40 Hz-ASSR (auditory steady state responses) could be valuable for objectively estimating the frequency-specific threshold in adults undergoing an expertise examination for medicolegal and/or compensation purposes. The present prospective study was set up to clarify the relationship between the thresholds obtained by cortical evoked response audiometry (CERA) and by 40 Hz-ASSR, in the same ears, within a large homogeneous sample of 164 subjects (328 ears) with NIHL and well documented exposure to noise. All these subjects claimed financial compensation for occupational NIHL, and there was a suspicion of exaggeration of the reported NIHLs. ASSR thresholds show a good correlation with the CERA thresholds. However, a systematic shift is noticed, ASSR thresholds being on average (1–2 – 3 kHz) 4.38 dB lower (i.e. showing less hearing loss) than CERA thresholds. Moreover, the binaural multiple ASSR technique allows a considerable time gain when compared to the CERA.

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