Pattern Ergs and Vep Topography Evoked by Lateral Eccentric Pattern Reversal Stimulation

Abstract

In ten healthy subjects we recorded simultaneously pattern-ERGs and multichannel VEPs evoked by checkerboard reversal stimuli presented in the center, and at three different locations on the nasal and temporal retina. In the near periphery significantly larger pattern-ERG amplitudes were found for the nasal retina. Farther out in the periphery this effect reversed, and stimuli presented to the temporal retina yielded larger pattern-ERG amplitudes. Component latencies showed also differences with larger latencies for nasal than temporal retinal stimuli in the near periphery. In addition, pattern-ERG amplitudes increased with check size while peak latencies decreased. Retinal stimulus location had a significant influence on the VEP topography reflected by potential distributions lateralized over occipital scalp areas contralateral to the hemiretina stimulated. There were no differences between VEP activity evoked by nasal or temporal retinal stimuli. The results relate to differences in local retinal organization reflected by the distribution of photoreceptors and other neural elements across the retina as well as to functional differences in visual information processing between different retinal areas.

Pattern Reversal ERG with LED-stimulation Using Cyclic Summation Technique*

“…An explanation for lowest amplitudes in the nasal upper field can be the optic nerve head laying in this quadrant, while both nasal fields have lower amplitudes than temporal fields because of higher density of blood vessels in this fields. A comparison of stimulation with a rectangular field (18 Â 14°) centrally and at different locations on the horizontal meridian shows in the near periphery larger PERG amplitudes in the nasal area, while more outward to periphery this effect reversed [30]. Our results seem to indicate similar amplitude behaviour on the horizontal meridian, while on the vertical meridian no difference between superior and inferior was detectable.…”

Pattern electroretinography in senile macular degeneration

“…Pattern stimulation reflects the macular function better than stimulation by flashes (even more so if pattern elements are small and presented with little contrast). Pattern electroretinography (PERG) is said to relate better to the topography of the posterior pole than pattern visual evoked potentials (PVEP) [14][15][16][17]. For these reasons the value of PERG in particular was assessed.…”