The attentional influence of new objects and new motion

Previous research on the attentional influence of new objects and new motion in the environment has focused on studying these two visual features in isolation. In the present study, we examined new objects and new motion when they co-occurred within one scene. In addition, we evaluated the extent to which low-level luminance changes can contribute to the attention-capturing properties of each of these dynamic events. Results suggest that new objects have a larger impact on the allocation of attention than new motion and, under certain circumstances, the appearance of new objects may suppress the attentional benefit typically afforded to new motion. Lastly, our findings indicate that low-level factors account for some, but not all, of the attentional effects observed for new objects and new motion.     

A new keratometer

A keratometer design is described which uses Drysdale's method for determining the radius of a curved surface with the use of a spherocylindrical lens system to allow simultaneous observation of the surface and center of curvature images. This not only results in a simple compact keratometer but also provides an instrument that can be used to measure the radius of curvature of the peripheral cornea.     

Metipranolol--a new beta-blocker

The beta-blocker Metipranolol is discussed with reference to a pilot study and a double-blind study. It was found to be remarkably effective in lowering intraocular pressure. No statistically significant difference was found between Metipranolol and Timolol with regard to their effect on intraocular pressure and blood circulation. Nor were any significant side effects observed.     

Retinovascular physiology and pathophysiology: new experimental approach/new insights

An important challenge in visual neuroscience is to understand the physiology and pathophysiology of the intra-retinal vasculature, whose function is required for ophthalmoception by humans and most other mammals. In the quest to learn more about this highly specialized portion of the circulatory system, a newly developed method for isolating vast microvascular complexes from the rodent retina has opened the way for using techniques such as patch-clamping, fluorescence imaging and time-lapse photography to elucidate the functional organization of a capillary network and its pre-capillary arteriole. For example, the ability to obtain dual perforated-patch recordings from well-defined sites within an isolated microvascular complex permitted the first characterization of the electrotonic architecture of a capillary/arteriole unit. This analysis revealed that this operational unit is not simply a homogenous synctium, but has a complex functional organization that is dynamically modulated by extracellular signals such as angiotensin II. Another recent discovery is that a capillary and its pre-capillary arteriole have distinct physiological differences; capillaries have an abundance of ATP-sensitive potassium (K(ATP)) channels and a dearth of voltage-dependent calcium channels (VDCCs) while the converse is true for arterioles. In addition, voltage transmission between abluminal cells and the endothelium is more efficient in the capillaries. Thus, the capillary network is well-equipped to generate and transmit voltages, and the pre-capillary arteriole is well-adapted to transduce a capillary-generated voltage into a change in abluminal cell calcium and thereby, a vasomotor response. Use of microvessels isolated from the diabetic retina has led to new insights concerning retinal vascular pathophysiology. For example, soon after the onset of diabetes, the efficacy of voltage transmission through the endothelium is diminished; arteriolar VDCCs are inhibited, and there is increased vulnerability to purinergic vasotoxicity, which is a newly identified pathobiological mechanism. Other recent studies reveal that K(ATP) channels not only have an essential physiological role in generating vasomotor responses, but their activation substantially boosts the lethality of hypoxia. Thus, the pathophysiology of the retinal microvasculature is closely linked with its physiology.