Rod Electroretinograms Elicited by Silent Substitution Stimuli from the Light-Adapted Human Eye

Maguire, John F.; Parry, Neil R. A.; Kremers, Jan; Kommanapalli, Deepika; Murray, Ian J.; McKeefry, Declan J.

doi:10.1167/tvst.5.4.13

Cited by 21 publications

(16 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, it was found that rod-driven ERG responses can also be obtained reliably at retinal illuminances up to about 400 td, without the need for extensive dark adaptations. 30 , 31 It is possible that the wnERG in combination with the rod-isolating silent substitution is a method to efficiently obtain rod-driven IRFs.…”

Section: Discussionmentioning

confidence: 99%

A Temporal White Noise Analysis for Extracting the Impulse Response Function of the Human Electroretinogram

Zele

Feigl

Kambhampati

et al. 2017

Trans. Vis. Sci. Tech.

Self Cite

View full text Add to dashboard Cite

PurposeWe introduce a method for determining the impulse response function (IRF) of the ERG derived from responses to temporal white noise (TWN) stimuli.MethodsThis white noise ERG (wnERG) was recorded in participants with normal trichromatic vision to full-field (Ganzfeld) and 39.3° diameter focal stimuli at mesopic and photopic mean luminances and at different TWN contrasts. The IRF was obtained by cross-correlating the TWN stimulus with the wnERG.ResultsWe show that wnERG recordings are highly repeatable, with good signal-to-noise ratio, and do not lead to blink artifacts. The wnERG resembles a flash ERG waveform with an initial negativity (N1) followed by a positivity (P1), with amplitudes that are linearly related to stimulus contrast. These N1 and N1-P1 components showed commonalties in implicit times with the a- and b-waves of flash ERGs. There was a clear transition from rod- to cone-driven wnERGs at ∼1 photopic cd.m−2. We infer that oscillatory potentials found with the flash ERG, but not the wnERG, may reflect retinal nonlinearities due to the compression of energy into a short time period during a stimulus flash.ConclusionThe wnERG provides a new approach to study the physiology of the retina using a stimulation method with adaptation and contrast conditions similar to natural scenes to allow for independent variation of stimulus strength and mean luminance, which is not possible with the conventional flash ERG.Translational RelevanceThe white noise ERG methodology will be of benefit for clinical studies and animal models in the evaluation of hypotheses related to cellular redundancy to understand the effects of disease on specific visual pathways.

show abstract

Section: Discussionmentioning

confidence: 99%

A Temporal White Noise Analysis for Extracting the Impulse Response Function of the Human Electroretinogram

Zele

Feigl

Kambhampati

et al. 2017

Trans. Vis. Sci. Tech.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The scotopic retinal illuminance, calculated from the scotopic spectral sensitivity of the eye (rods) and the stimulus spectral distribution, was approximately 5600 scot Td considering 8 mm pupil diameter and the photopic retinal illuminance was 14275 Td. It was previously shown that in ERG measurements rod isolating stimuli (25% rod contrast) did not elicit significant rod driven responses above about 400 Td (Maguire et al, 2016). Therefore, rod-driven signals are negligibly small.…”

Section: Visual Stimulationmentioning

confidence: 94%

L-/M-cone opponency in visual evoked potentials of human cortex

et al. 2017

Self Cite

View full text Add to dashboard Cite

L and M cones send their signals to the cortex using two chromatic (parvocellular and blue-yellow koniocellular) and one luminance (magnocellular) pathways. These pathways contain ON and OFF subpathways that respond to excitation increments and decrements respectively. Here, we report on visually evoked potentials (VEP) recordings that reflect L- and M-cone driven increment (LI and MI) and decrement (LD and MD) activity. VEP recordings were performed on 12 trichromats and four dichromats (two protanopes and two deuteranopes). We found that the responses to LI strongly resembled those to MD, and that LD and MI responses were very similar. Moreover, the lack of a photoreceptor type (L or M) in the dichromats led to a dominance of the ON pathway of the remaining photoreceptor type. These results provide electrophysiological evidence that antagonistic L/M signal processing, already present in the retina and the lateral geniculate nucleus (LGN), is also observed at the visual cortex. These data are in agreement with results from human psychophysics where MI stimuli lead to a perceived brightness decrease whereas LI stimuli resulted in perceived brightness increases. VEP recording is a noninvasive tool that can be easily and painlessly applied. We propose that the technique may provide information in the diagnosis of color vision deficiencies.

show abstract

“…In order to create silent substitution stimuli, photoreceptor excitations were calculated by multiplying the emission spectra of the LEDs with cone fundamentals and the V’ λ 10° function [ 22 , 23 ] and integrating over a range of wavelengths (see: Ref. [ 13 ] for a fuller description of stimulus generation). The stimuli used in these experiments were triple silent substitutions in which intensity and wavelength combinations were used which produced no change in the net excitation of L-, M- or S-cones, but did produce excitation modulation of rod photoreceptors.…”

Section: Methodsmentioning

confidence: 99%

“…In a previous study, we demonstrated that it is possible to isolate rod-mediated steady-state (8 Hz) ERG responses using the silent substitution method without the need for dark adaptation [ 13 ]. We were able to show that ERGs elicited by this technique were selective for rods by the demonstration of a correspondence between temporal frequency and illuminance response characteristics and previously reported psychophysical properties of rod-mediated vision.…”

Section: Introductionmentioning

confidence: 99%

The morphology of human rod ERGs obtained by silent substitution stimulation

et al. 2017

View full text Add to dashboard Cite

PurposeTo record transient ERGs from the light-adapted human retina using silent substitution stimuli which selectively reflect the activity of rod photoreceptors. We aim to describe the morphology of these waveforms and examine how they are affected by the use of less selective stimuli and by retinal pathology.MethodsRod-isolating stimuli with square-wave temporal profiles (250/250 ms onset/offset) were presented using a 4 primary LED ganzfeld stimulator. Experiment 1: ERGs were recorded using a rod-isolating stimulus (63 ph Td, rod contrast, C rod = 0.25) from a group (n = 20) of normal trichromatic observers. Experiment 2: Rod ERGs were recorded from a group (n = 5) using a rod-isolating stimulus (C rod = 0.25) which varied in retinal illuminance from 40 to 10,000 ph Td. Experiment 3: ERGs were elicited using 2 kinds of non-isolating stimuli; (1) broadband and (2) rod-isolating stimuli which contained varying degrees of L- and M-cone excitation. Experiment 4: Rod ERGs were recorded from two patient groups with rod monochromacy (n = 3) and CSNB (type 1; n = 2).ResultsThe rod-isolated ERGs elicited from normal subjects had a waveform with a positive onset component followed by a negative offset. Response amplitude was maximal at retinal illuminances <100 ph Td and was virtually abolished at 400 ph Td. The use of non-selective stimuli altered the ERG waveform eliciting more photopic-like ERG responses. Rod ERGs recorded from rod monochromats had similar features to those recorded from normal trichromats, in contrast to those recorded from participants with CSNB which had an electronegative appearance.ConclusionsOur results demonstrate that ERGs elicited by silent substitution stimuli can selectively reflect the operation of rod photoreceptors in the normal, light-adapted human retina.

show abstract

Rod Electroretinograms Elicited by Silent Substitution Stimuli from the Light-Adapted Human Eye

Cited by 21 publications

References 55 publications

A Temporal White Noise Analysis for Extracting the Impulse Response Function of the Human Electroretinogram

A Temporal White Noise Analysis for Extracting the Impulse Response Function of the Human Electroretinogram

L-/M-cone opponency in visual evoked potentials of human cortex

The morphology of human rod ERGs obtained by silent substitution stimulation

Contact Info

Product

Resources

About