different software tools for quantification of myocardial perfusion spect (mps) studies are routinely used. several perfusion parameters can be computed automatically.  interpretation of the mps should start with visual inspection of the rotating planar images, visual analysis of reconstructed spect slices and then quantitative analysis to confirm the visual impression. quantification should be...

Let’s examine the foveal vision a bit closer. This type of vision concerns the focussing of the eye. The eye can try to follow a certain moving object. We then have pursuit eye movements. Alternatively, the eye can jump from one place to another place. We are then dealing with saccadic eye movements. Important parameters are now the location of the focus, as well as the dwell time, which is the...

A compact genome and a tiny brain make Drosophila the prime model to understand the neural substrate of behavior. The neurogenetic efforts to reveal neural circuits underlying Drosophila vision started about half a century ago, and now the field is booming with sophisticated genetic tools, rich behavioral assays, and importantly, a greater number of scientists joining from different backgrounds...

1. In the rods of fresh-water and some anadromous fishes, rhodopsin is replaced by the purple photolabile pigment porphyropsin. This participates in a retinal cycle identical in form with that of rhodopsin, but in which new carotenoids replace retinene and vitamin A. 2. Porphyropsin possesses a broad absorption maximum at 522 +/- 2 mmicro, and perhaps a minimum at about 430 mmicro. The vitamin ...

Modern neuroscience, of which the study of the visual system is an integral part, has surprisingly recent beginnings. Its cornerstone, the neuron doctrine, was formulated late in the 19th century, to a large extent as a result of evidence collected by Santiago Ramon y Cajal using the fortuitously discovered Golgi method. Ironically, the idea that nerve cells were independent biological units wa...

As part of a forthcoming planetarium show about the human brain, we are producing realistic models of the central nervous system at a variety of scales, from whole brain images to images of individual neurons. We have focused on the visual system and especially the visual cortex, and are building sets of simulated neurons using stochastic growth rules that mimic the geometries of actual neurons...

Different software tools for quantification of myocardial perfusion SPECT (MPS) studies are routinely used. Several perfusion parameters can be computed automatically.  Interpretation of the MPS should start with visual inspection of the rotating planar images, visual analysis of reconstructed SPECT slices and then quantitative analysis to confirm the visual impression. Quantification should be...

Abstract Background: Opium-dependence having different effects on the nervous system is a common problem, especially in the Middle East and Iran. The aim of this study is evaluating the effects of opium-dependence on visual evoked potential (VEP) in men. Methods: Thirty subjects with both chronic cigarette smoking and opium-dependence (group 1) and 30 subjects with only chronic ciga...