Cones show a differential sensitivity to light coming from different portions of the pupil, typically being most sensitive to light from the center of the pupil. We measured the directional properties of the cones across the central 6 deg of the retina, using an optical imaging technique. We find that the cones in the center of the fovea have the broadest tuning. The width of the angular tuning...

UNLABELLED PREMISE OF THE STUDY Thermogenesis is a prominent pollination-related feature of cycad cones and is generally assumed to play a role in pollination. Although typically studied just before, during, and immediately after the cones' pollination phase, thermogenesis may be present in other cone developmental phases. • METHODS We assayed thermogenesis in Cycas micronesica, Guam's end...

The photoreceptors of the barred owl (Strix varia) consist of rods, single cones and unequal double cones present in a ratio of about 35:1:3. In the light-adapted condition the rods are of uniform diameter along their entire length and are therefore not felt to undergo photomechanical changes. The rod outer segment consists of a stack of scalloped bimembranous discs enclosed in a limiting membr...

Besides woody cone scales, certain species of wind-dispersed pines (Pinus) have spines on their scales as a putative form of defense against seed predators. We tested whether spines differentially deterred seed predators foraging on closed and open pine cones. Red Crossbills (Loxia curvirostra) were selected as the seed predator because they commonly forage on these cones. We timed crossbills f...

During central nervous system development, neurons differentiate distinct axonal and dendritic processes whose outgrowth is influenced by environmental cues. Given the known intrinsic differences between axons and dendrites and that little is known about the response of dendrites to inhibitory cues, we tested the hypothesis that outgrowth of differentiating axons and dendrites of hippocampal ne...

Based on the equivalence relation on a linear space, in this paper we introduce the definition of rough convex cones and rough convex fuzzy cones and discuss some of the fundamental properties of such rough convex cones.

1. The dynamic properties of the microcircuitry formed by cones and horizontal cells in the isolated goldfish retina were studied. Cones project to horizontal cells and horizontal cells feed back to cones via a relatively slow negative feedback pathway. 2. The time constant of the feedback signal in cones and of the effect this feedback signal had on the responses of second-order neurons was de...

In mammals, each cone had been thought to contain only one single type of photopigment. It was not until the early 1990s that photopigment coexpression was reported. In the house mouse, the distribution of color cones shows a characteristic division. Whereas in the upper retinal field the ratio of short wave to middle-to-long wave cones falls in the usual range (1:10), in the ventral retinal fi...

The number of species that specialize in pre-dispersal seed predation is relatively small. Examples of specialized pre-dispersal seed predators adapted to feeding on closed cones include vertebrate species like Crossbills, Squirrels, Nutcrackers and Woodpeckers. Seed predation selects against certain phenotypic features of cones and favors another phenotypic features. In this study, we document...

A negative phototransduction feedback in rods and cones is critical for the timely termination of their light responses and for extending their function to a wide range of light intensities. The calcium feedback mechanisms that modulate phototransduction in rods have been studied extensively. However, the corresponding modulation mechanisms that enable cones to terminate rapidly their light res...