Using the rotating striped cylinder device previously employed for determination of the flicker response function with lower animals, corresponding measurements have been made with human observers. The curves based upon the relation between critical flash frequency and critical intensity for the signalling of the recognition of flicker have the properties of human flicker fusion data as obtaine...

The influence of refractive defocus and artificial media opacities on perimetric thresholds in automated light-sense and flicker perimetry was investigated in 20 eyes of 20 normal subjects. Thresholds were determined at 13 locations in the central visual field up to 25 degrees. Refractive defocus was induced by blurring with glasses of +1, +2, +3, +6 and +9 diopters spherical. Three diffusers w...

The electroretinogram (ERG) of hemeralopic Alaskan malamute dogs contains only rod components. There is absence of the photopic b-wave which is normally elicited with red light stimuli during dark adaptation and, using flicker stimulation, only the first or rod branch of the flicker fusion response curve is present. At high stimulus intensity levels, the flicker response of hemeralopes is absen...

The changes in apparent brightness or color, induced into a test spot by a surround, can be greatly enhanced either by flickering the test spot between two luminances, or by binocularly fusing a pair of test spots of different luminances. Simultaneous contrast, in which a white surround makes a grey spot look darker, is greatly enhanced if the spot (not the surround) flickers between black and ...

BACKGROUND Imaging studies show that placebo enhance release of dopamine in the mesolimbic and mesocortical tracts. Dopamine in these areas are involved in attention and working memory function. PURPOSE We wanted to investigating the effect of placebo on psychomotor function and working memory capacity. METHOD 31 medical students participated in this single blind, crossover trial. Choice re...

For over 150 years, researchers have investigated the anti-predator function of animal patterns. However, this work has mainly focused on when prey remain still, and has only recently started to incorporate motion into the study of defensive coloration. As motion breaks camouflage, a new challenge is to understand how prey avoid predators while moving around their environment, and if a moving p...

OBJECTIVE Exploration of the variable effect of the degree of smoking dependence on psychomotor performance and working memory capacity. METHODS This is a randomized, controlled, prospective study conducted in the Department of Pharmacology, College of Medicine, Al-Mustansiriya University, Baghdad, Iraq from 15 January 2011 to 25 February 2011. After third stage male medical students complete...