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R L Klingaman

Publications and source records attributed to R L Klingaman.

8 recordsLinked to original sources
PubMed1984

A rod monochromat's pattern VECP at high and low background levels: spatial tuning of colour mechanisms and rods compared.

The visually evoked cortical potential spatial-tuning function, i.e. checksize vs amplitude of response, was determined for a rod monochromat at a low background level of 0.2 scot td or a high background level of 200 scot td. The results showed evidence of a peak at 36' for the low-background spatial-tuning curve, but almost no peak was evident when the high background level was employed. This latter finding was interpreted as consistent with a rod saturation effect. Additionally, the shape of the spatial-tuning function found with the low background level was compared with that obtained from the blue or red (R) and green (G) cone mechanisms of normals. It was concluded that the blue cone mechanism may not use, as has been hypothesized, the same neural transmission pathway as rods because its spatial-tuning curve differed from both the rod and R and G systems.

Adult↗
PubMed1979

Assessment of the visual acuity of human color mechanisms with the visually evoked cortical potential.

The amplitude of the human visually evoked cortical potential (VECP), which has been shown to vary as a function of the dimensions of checks in a checkerboard pattern, was used to objectively assess the visual acuity of the blue-sensitive compared with the red- and green-sensitive mechanisms in the eye. The results agree with psychophysical measures which have indicated poorer acuity of the blue system compared with the red and green systems.

Adult↗
PubMed1977

A comparison of psycholphysical and VECP increment threshold functions of a rod monochromat.

Increment thresholds of a rod monochromat were obtained over a wide range of background luminances. Within each experimental session, visual-evoked cortical potentials (VECP's) were computed at several luminance levels above the increment threshold for each background level. The results indicate that as the background level approached 1,000 scotopic trolands (td.), the VECP began to decrease in amplitude and it was unrecordable above 2,000 scotopic td. The VECP increment threshold function was determined with latency used as the criterion response. Good agreement was found between the psychophysical and VECP functions, although the VECP function did show a tendency to underestimate the threshold at the two dimmest background levels. It is concluded that the dramatic drop in the VECP amplitude at high background luminances is a reflection of the saturation of the rod system and that the VECP appears to be a sensitive correlate of the psychophysical data.

Adult↗