June 2022
Volume 63, Issue 7
Open Access
ARVO Annual Meeting Abstract  |   June 2022
Y-like behavioral responses to contrast-modulated patterns as a specific test of the magnocellular pathway
Author Affiliations & Notes
  • Ana Ramirez
    Ophthalmology, McGill University, Montreal, Quebec, Canada
  • Lowell W Thompson
    Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, United States
  • Ari Rosenberg
    Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, United States
  • Curtis Baker
    Ophthalmology, McGill University, Montreal, Quebec, Canada
  • Footnotes
    Commercial Relationships   Ana Ramirez Based on these findings the technology transfer office for UW-Madison (WARF) has filed a patent application (pending) with Ari Rosenberg, Curtis Baker and Ana Ramirez listed as inventors., Code P (Patent); Lowell Thompson None; Ari Rosenberg As for first author, Code P (Patent); Curtis Baker As for first author, Code P (Patent)
  • Footnotes
    Support  Supported by Canadian NSERC grant OPG0001978 to C.B. and National Institutes of Health Grant EY029438 to AR.
Investigative Ophthalmology & Visual Science June 2022, Vol.63, 2548 – F0502. doi:
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    • Get Citation

      Ana Ramirez, Lowell W Thompson, Ari Rosenberg, Curtis Baker; Y-like behavioral responses to contrast-modulated patterns as a specific test of the magnocellular pathway. Invest. Ophthalmol. Vis. Sci. 2022;63(7):2548 – F0502.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : The primate magnocellular pathway originates in parasol retinal ganglion cells, which like Y-cells of the cat, respond nonlinearly to high spatial frequencies (SFs) and temporal frequencies (TFs). However, the contribution of Y-like cells to human visual perception are not well understood.
The contrast-modulated (CM) stimuli used here were composed of high SF contrast-reversing grating carriers that were contrast modulated by a low SF drifting sinewave envelope. Since CM carrier-tuned responses in visual cortex are mediated by Y-cell inputs, we hypothesized that human psychophysical performance for CM stimuli might reflect properties of nonlinear Y-like cells, rather than linear responses to conventional gratings.

Methods : Healthy subjects (N=6) reported the direction of motion of CM envelopes or luminance-modulated (LM) gratings from 2.1-8.5 degrees of eccentricity. SF (for LMs) or carrier SF (for CMs) was varied for different values of TF (LMs) or carrier TF (CMs).

Results : LM performance was low-pass with SF, with the cut-off systematically decreasing with TF. CM performance was bandpass with carrier SF, with best performance at high carrier SFs (1.5-3.0cpd) and TFs (15-20Hz). These observations were confirmed with an ANOVA, showing a significant effect of carrier SF, p<0.05, but not carrier TF, p=0.1, or their interaction, p=0.75. The eccentricity-dependence also differed for LM and CM stimuli. At the highest TF (20Hz), the low-pass LM performance decreased systematically with eccentricity, while CM performance was bandpass with carrier SF, and rather independent of eccentricity. An ANOVA showed a significant main effect for the carrier-SF, p=<0.05, but not eccentricity F(3,2)=0.8, p=0.48, or their interaction, p=0.56.

Conclusions : Since nonlinear subunits of Y-like cells respond better at higher TFs than linear mechanisms respond to gratings, the psychophysical performance for CMs is consistent with Y-like cells. The good performance for CM stimuli at carrier SFs that are high for peripheral vision and the relative independence of eccentricity are also consistent with responses of small Y-like nonlinear subunits. These results suggest that our CM behavioral task provides a specific indicator of the functioning of Y-like cells in human vision. This might be relevant to assessing pathologies related to damage in the magnocellular pathway, including glaucoma.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

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