Bradycardia from flash stimulation

AbstractThis study aimed to analyze the neuronal sources of the visual evoked potentials after flash stimulation of the S- and the L/M-cone driven channels of the visual system. For 11 volunteers a 64-channel electroencephalography (EEG) was recorded during selective excitation of both color opponent channels. Individual and grand average data were analyzed topographically. Source localization was carried out using a realistically shaped three compartment boundary element model (BEM) and a mirrored moving dipole model. We found two main components (N1, P1) in all subjects, as well as a third late component in most subjects. For these components significant latency differences (N1=33 ms, P1=22 ms; p<0.05) between both color opponent channels were found. The results showed no differences in the topography and no differences in dipole localization between both color channels. Talairach coordinates of grand averages indicated activation in area 18. Comparison of results of separately stimulated eyes revealed no differences. Our findings showed that neural processing occurs in the same areas of the visual cortex for stimuli with different spectral properties. The signals of S- and L/M-cone driven channels are transmitted in distinct pathways to the cortex. Thus, the observed latency differences might be caused by different anatomical and functional properties of these pathways.

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Time Course of the Cerebral Slow Potential Changes Caused by Rhythmic Flash Stimulation

The Tohoku Journal of Experimental Medicine ◽

10.1620/tjem.108.195 ◽

1972 ◽

Vol 108 (2) ◽

pp. 195-196

Author(s):

TOSHIYUKI OZAKI ◽

SECHIKO SASAKI

Keyword(s):

Time Course ◽

Slow Potential ◽

Flash Stimulation

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Responsiveness of the Visual System in Childhood Migraine Studied by Means of VEPs

Cephalalgia ◽

10.1046/j.1468-2982.1986.0603183.x ◽

1986 ◽

Vol 6 (3) ◽

pp. 183-185 ◽

Cited By ~ 31

Author(s):

Mario Brinciotti ◽

Vincenzo Guidetti ◽

Maria Matricardi ◽

Flavia Cortesi

Keyword(s):

Light Intensity ◽

Visual System ◽

Visual Evoked Potential ◽

Evoked Potential ◽

Control Group ◽

Pattern Reversal ◽

Childhood Migraine ◽

Free Interval ◽

Flash Stimulation ◽

Visual Evoked

We have tried to ascertain whether the increased visual evoked potential (VEP) amplitude found in adult migraineurs is present also in children with migraine. We investigated 43 children, 26 male and 17 female, with a mean age of 11.4 years, 24 with common and 19 with classic migraine, and compared them with a control group of 20 children, 11 male and 9 female, with a mean age of 9.7 years. Flash and pattern reversal VEPs were recorded in both groups, and the study was carried out in the pain-free interval between attacks. The children with migraine showed a significant ( p < 0.01) increase in VEP amplitude on flash stimulation but not on pattern reversal. There were no differences between classic and common migraine. The abnormal responsiveness of the visual system seems to be related to variations in light intensity rather than to spatial contrasts.

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