Detection of short time delays between photic stimuli by means of pattern induced flicker colors (PIFCs)

Experiments with a disc of the type of Benhams top. The black and white pattern on the rotating disc fuses, resulting in two concentric rings of different color. The threshold of detection of color differences between the rings was studied as a function of the pattern and the frequency of rotation. Result: relative shifts in time between photic stimuli at neighboring retinal areas of less than 1 msec may alter the color. The effect of these short time differences is hypothetically attributed to the activity of the horizontal cells.     

Some observations on temporal coding of color vision: psychophysical results

Direction reversal of Benham's disk changes the observed colors, yet leaves constant the magnitude-frequency spectrum of the stimulus, changing only the phase relations between temporal frequencies. Hence, human color channels must be selectively responsive to stimulus temporal phase information.This question was further tested by applying to the eye electrical stimuli composed of sequences of frequency-modulated corneo-positive and negative pulses, which bypass at least some stages of the light-to-spike transfer function. Stimuli with a fast-slow corneonegative pulse frequency sequence elicited phosphenes in the range of yellow to green, for the four subjects tested. Stimuli with a slow-fast sequence elicited red-magenta, again for all four subjects.Convolution of previously derived Benham's disk-like signals for green-yellow and red-magenta with a published impulse function for the visual system resulted in output functions which were compatible with the frequency-time envelopes of the above electrical signals, providing independent support for the results.     

C-Reactive Protein in Giant Cell (Cranial,Temporal) Artentis

A controlled study of C-reactive protein in patients with and without temporal arteritis was performed. C-reactive protein was elevated in 10 of 11 patients with biopsy-proven temporal arteritis before treatment. It was positive in 14 of 32 control patients with negative temporal artery biopsies. This difference is statistically significant. C-reactive protein was elevated in 6 to 9 (depending on the adequacy of therapy) of 34 patients with temporal arteritis after corticosteroids were started. C-reactive protein and erythrocyte sedimentation rate are positively correlated in untreated arteritis. Clinical correlation showed C-reactive protein was more sensitive than the erythrocyte sedimentation rate in following the adequacy of corticosteroid dosages in temporal arteritis probably because many more noninflammatory factors influence erythrocyte sedimentation than influence C-reactive protein.