Simple motor reaction time (RT) to 100 percent negative contrast stimuli was measured for various background luminances as well as after bleaching a fraction of retinal photopigments. RT decreased to asymptotical value with the increase of background intensity. The intensity-dependent portion of RT behaved identically for 100 percent positive and negative contrast. Moreover, RT to 100 percent n...

This report proposes a standard method to characterize variability and sensitivity of functional neuroimaging experiments. Most functional neuroimaging analyses result in statistic images of signal-to-noise. However, it is essential to examine both signal and noise individually, to characterize sensitivity and to identify artifacts. Confidence intervals simultaneous convey signal and noise but ...

The difference between the disease rates of two groups, one exposed and one not exposed to a suspected aetiological factor, is a useful measure of the risk associated with the factor. This measure is of most interest when the association is considered causal, and has been termed the attributable risk (MacMahon and Pugh, 1970). Expressed as a percentage of the total disease rate in a group (the ...