Signal Pathways in the Electroretinogram

Kremers, Jan

doi:10.5772/21695

Cited by 5 publications

(3 citation statements)

References 59 publications

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“…There are indications that similar compensatory mechanisms are present in the parvocellular channel (Kremers, 2003(Kremers, , 2011Kremers et al, 2000;Kremers, Stepien, Scholl & Saito, 2003). Perhaps the ERGs to sawtooth stimuli reflect some aspects of parvocellular activity.…”

Section: Discussionmentioning

confidence: 98%

Asymmetries in the contributions of On- and Off-mechanisms to the ERG signal.

Kremers¹

2013

Psychology & Neuroscience

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ERG responses were recorded to rapid-on and rapid-off L-and M-cone isolating sawtooth stimuli of different cone contrasts. In addition, the responses were recorded to simultaneous in-phase stimulation of the L-and M-cones at equal cone contrast. Linear responses to mirror imaged rapid-on and rapid-off sawtooth stimuli are also mirror imaged. By adding on-and offresponses, linear response components will cancel and nonlinearities will remain. Because nonlinearities that occur at a certain stage of visual processing will influence subsequent stages, linear response components will probably have an outer retinal origin and nonlinearities probably originate mainly in the inner (post-receptoral) retina.

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Section: Discussionmentioning

confidence: 98%

Asymmetries in the contributions of On- and Off-mechanisms to the ERG signal.

Kremers¹

2013

Psychology & Neuroscience

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“…This suggests the presence of a compensatory mechanism because the signal output remains relatively constant although the cone signal input may vary considerably. A compensatory mechanism was also proposed to explain the similar responses of cone-opponent ERGs to L- and M-cone isolating stimuli with equal cone contrasts [ 4 , 12 ] and the similar psychophysical detection sensitivities to L- and M-cone isolating stimuli at low temporal frequencies (where the chromatic pathway is responsible for the task) [ 13 ] because L-cone packing density is generally larger than M-cone density in trichromatic subjects. Possibly, the two compensatory mechanisms have identical origins.…”

Section: Discussionmentioning

confidence: 99%

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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“…We previously proposed that the midget bipolar cells have similar physiological properties as the midget retinal ganglion cells belonging to the L-/M-opponent sensitive parvocellular pathway. Additionally, we suggest that diffuse bipolar cells are luminance sensitive similar to the parasol retinal ganglion cells (belonging to the magnocellular pathway) [ 5 , 6 ]. Which of the two pathways dominates in the ERG response depends on the stimulus size and on its temporal frequency.…”

Section: Introductionmentioning

confidence: 99%

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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Signal Pathways in the Electroretinogram

Cited by 5 publications

References 59 publications

Asymmetries in the contributions of On- and Off-mechanisms to the ERG signal.

Asymmetries in the contributions of On- and Off-mechanisms to the ERG signal.

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

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