Rod- versus cone-driven ERGs at different stimulus sizes in normal subjects and retinitis pigmentosa patients

Aher, Avinash J.; McKeefry, Declan J.; Parry, Neil R. A.; Maguire, John F.; Murray, IJ; Tsai, Tina I.; Huchzermeyer, Cord; Kremers, Jan

doi:10.1007/s10633-017-9619-5

Cited by 10 publications

(9 citation statements)

References 27 publications

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“…The gradual amplitude changes are an indication of intrusion of rod signals. This was previously found for spatially restricted stimuli that were created with black cardboard [11]; the intrusion was considerably weaker if a constant luminance in the surround was introduced. Furthermore, rod isolating photopic stimuli elicited responses that were larger with spatially restricted stimuli when compared to full field stimuli.…”

Section: Discussionsupporting

confidence: 68%

The spatial distribution of ERGs reflecting luminance and L-/M-cone-opponent signals

et al. 2021

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Purpose To study the spatial retinal distribution of electroretinographic (ERG) responses that reflect signals in the L-/M-cone-opponent and luminance post-receptoral pathways. Methods ERG recordings to heterochromatic stimuli (sinusoidal counter-phase modulation of red and green LED light sources) were performed, while varying fractions of red and green modulation. Two temporal frequencies of the stimuli were employed: 12 Hz to record ERGs that reflect L-/M-cone-opponent signal and 36 Hz for recording ERG signals sensitive to stimulus luminance. Stimuli were about 20° in diameter and projected on various retinal locations: the fovea and four eccentricities (10°, 19°, 28° and 35°), each presented nasally, temporally, inferiorly and superiorly from the fovea. Results The 36 Hz stimuli elicited responses that strongly varied with red fraction and were minimal at iso-luminance. Moreover, response phases changed abruptly at the minimum by 180°. In contrast, the responses to the 12 Hz stimuli had amplitudes and phases that changed more gradually with red fraction. The 36 Hz response amplitudes were maximal close to the fovea and sharply decreased with increasing distance from the fovea. The responses to 12 Hz stimuli were more broadly distributed across the retina. Conclusions In the present study, it was found that retinal eccentricity and direction from the fovea have distinct effects on ERGs reflecting different post-receptoral mechanisms. The results are in accord with previous findings that ERGs to 12 Hz stimuli are predominantly determined by the red–green chromatic content of the stimuli, thus reflecting activation in the L-/M-cone-opponent pathway, while responses to 36 Hz stimuli manifest post-receptoral luminance-dependent activation. We found that the response in the cone-opponent pathway is broadly comparable across the retina; in comparison, response amplitude of the luminance pathway strongly depends on retinal stimulus position.

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Section: Discussionsupporting

confidence: 68%

The spatial distribution of ERGs reflecting luminance and L-/M-cone-opponent signals

et al. 2021

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“…Each plot displays the data for the three stimulus sizes together with the fits of a vector addition of the FF 12 Hz and FF 36 Hz responses (FF: data black circles, fits black drawn lines; 70°: data red inverted triangles, fits red long dashed lines; 30°: data green squares, fits green short dashed lines) intermediate temporal frequencies with 30°stimuli. We attribute this to intrusion of rod-driven responses through stray light [13]. These effects were found for all four subjects.…”

Section: First Harmonic Componentsmentioning

confidence: 63%

The influence of temporal frequency and stimulus size on the relative contribution of luminance and L-/M-cone opponent mechanisms in heterochromatic flicker ERGs

et al. 2021

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Purpose To study the effect of stimulus size and temporal frequency on the relative contribution of luminance and L-/M-cone opponent signals in the ERG. Methods In four healthy, color normal subjects, ERG responses to heterochromatic stimuli with sinusoidal, counter-phase modulation of red and green LEDs were measured. By inverse variation of red and green contrasts, we varied luminance contrast while keeping L-/M-cone opponent chromatic contrast constant. The first harmonic components in the full field ERGs are independent of stimulus contrast at 12 Hz, while responses to 36 Hz stimuli vary, reaching a minimum close to isoluminance. It was assumed that ERG responses reflect L-/M-cone opponency at 12 Hz and luminance at 36 Hz. In this study, we modeled the influence of temporal frequency on the relative contribution of these mechanisms at intermediate frequencies, measured the influence of stimulus size on model parameters, and analyzed the second harmonic component at 12 Hz. Results The responses at all frequencies and stimulus sizes could be described by a linear vector addition of luminance and L-/M-cone opponent reflecting ERGs. The contribution of the luminance mechanism increased with increasing temporal frequency and with increasing stimulus size, whereas the gain of the L-/M-cone opponent mechanism was independent of stimulus size and was larger at lower temporal frequencies. Thus, the luminance mechanism dominated at lower temporal frequencies with large stimuli. At 12 Hz, the second harmonic component reflected the luminance mechanism. Conclusions The ERGs to heterochromatic stimuli can be fully described in terms of linear combinations of responses in the (magnocellular) luminance and the (parvocellular) L-/M-opponent retino-geniculate pathways. The non-invasive study of these pathways in human subjects may have implications for basic research and for clinical research.

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“…Luminance signals are relatively small in M-cone driven responses. 19,35 A significant difference between normal subjects and glaucoma patients was only found for the LN L-add component to 70°stimuli. This suggests that luminance driven responses are mainly affected by glaucoma because the luminance response is small in the M-cone driven responses.…”

Section: Discussionmentioning

confidence: 90%

“…There is evidence that ERGs elicited by cone and rod specific stimulation using the silent substitution technique can be useful to study the retinal abnormalities which affect vision. [19][20][21][22][23] Electroretinograms elicited by photoreceptor excitation increments (ON-ERG) and decrements (OFF-ERG) have components with distinct properties. 13,24 By employing periodic sawtooth stimuli of moderate frequency (4 Hz), ONand OFF-ERG responses can be reliably recorded.…”

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Responses of Postreceptoral Pathways Elicited by L- and M-Cone Isolating ON- and OFF-Electroretinograms in Glaucoma Patients

Aher

Horn

Huchzermeyer

et al. 2021

Invest. Ophthalmol. Vis. Sci.

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To compare the electroretinographical (ERG) responses elicited by L-and Mcone isolating ON-and OFF-sawtooth stimuli in normal subjects and glaucoma patients.METHODS. Twenty-one normal subjects and 44 primary open-angle glaucoma patients participated in the study. L-and M-cone isolating (18% cone contrast; 284 cd/m 2 ) rapid ON-and rapid OFF-sawtooth (4 Hz) stimuli with two stimulus sizes (full-field (FF) and central 70°diameter) were generated using the triple silent substitution technique. ONand OFF-response asymmetries were studied by adding the two (to obtain L-add and M-add responses). The initial positive (P) and subsequent late negative (LN) components of the L-add and M-add ERGs were compared between the subject groups and correlated with retinal nerve fiber layer thickness (RNFLT) and pattern ERG responses. RESULTS.The responses to L-ON and to M-OFF stimuli and vice versa resembled each other particularly with 70°stimuli. The P L-add amplitudes were not significantly different between the normal subjects and glaucoma patients, whereas the LN L-add amplitude was significantly (P < 0.01) smaller in the glaucoma patients. Both P M-add and LN M-add were not significantly different between the subject groups. The PERG amplitude with 0.8°check sizes and the 0.8°/16°amplitude ratio (PERG ratio) were significantly (P < 0.05) different between the subject groups. The 70°LN L-add amplitude and the 0.8°PERG amplitude were significantly correlated with RNFLT. CONCLUSIONS.The ERGs to 70°cone isolating sawtooth stimuli reflect cone opponency. The cone opponent ERG responses were not significantly different between glaucoma patients and normal subjects. Luminance driven L-add responses were significantly different, indicating that central luminance signals are mainly affected in glaucoma.

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Rod- versus cone-driven ERGs at different stimulus sizes in normal subjects and retinitis pigmentosa patients

Cited by 10 publications

References 27 publications

The spatial distribution of ERGs reflecting luminance and L-/M-cone-opponent signals

The spatial distribution of ERGs reflecting luminance and L-/M-cone-opponent signals

The influence of temporal frequency and stimulus size on the relative contribution of luminance and L-/M-cone opponent mechanisms in heterochromatic flicker ERGs

Responses of Postreceptoral Pathways Elicited by L- and M-Cone Isolating ON- and OFF-Electroretinograms in Glaucoma Patients

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