The necessity of a perception–action approach to definite distance perception: Monocular distance perception to guide reaching.

In this investigation of monocular perception of egocentric distance, the authors advocate the necessity of a perception–action approach because calibration is intrinsic to definite distance perception. A helmet-mounted camera and display were used to isolate optic flow generated by participants' head movements toward a target, and participants' reaches to place a stylus either in a target hole (Experiments 1, 2, and 4) or aligned under a target surface (Experiment 3) were analyzed. Conclusions are that binocular distance perception is accurate, monocular distance perception yields compression that is not eliminated by feedback, but feedback is used to eliminate underestimation generated by restriction of the size of the visual field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neural encoding of subject-object distance in a visual recognition system

Steroid actions on the vascular wall have been thought to depend on direct, genomic mechanisms being characterized by a considerable delay and on secondary events, including changes of coagulation, plasma lipids, and renal electrolyte and volume regulation. Recently, rapid effects of steroids on the vascular wall have been reported being clearly incompatible with the classical theory of genomic steroid action. As these effects occur in classical target tissues for genomic steroid action, and modulation of intracellular signaling has been shown to influence genomic steroid action, a two-step model of steroid action was developed integrating both genomic and nongenomic aspects and their possible interaction. This review summarizes recent studies on both types of direct, vascular steroid actions, the swift and the sluggish ones, and discusses the role of these actions in regulation of circulatory homeostasis and their potential therapeutic implications.