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Receptive Field Mosaics of Parasol and Midget Ganglion Cells in the Primate Retina

Receptive Field Mosaics of Parasol and Midget Ganglion Cells in the Primate Retina. Jeff Gauthier, PhD student Computational Neurobiology, UC-San Diego E.J. Chichilnisky’s lab, Salk Institute, San Diego, CA. Research Groups. E.J. Chichinlisky Salk Institute. Alan Litke UC-Santa Cruz.

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Receptive Field Mosaics of Parasol and Midget Ganglion Cells in the Primate Retina

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  1. Receptive Field Mosaics of Parasol and Midget Ganglion Cells in the Primate Retina Jeff Gauthier, PhD student Computational Neurobiology, UC-San Diego E.J. Chichilnisky’s lab, Salk Institute, San Diego, CA

  2. Research Groups E.J. Chichinlisky Salk Institute Alan Litke UC-Santa Cruz Greg Field Jon Shlens Eric Frechette Dumitru Petrusca Sasha Sher Matthew Grivich

  3. Functional Characterization of Parasols and Midgets • What is the relationship between receptive field (RF) and dendritic field (DF)? • How does coverage of parasols and midgets differ? • Are the ON-OFF asymmetries of parasols also found in midgets?

  4. Multielectrode Array Recording Ganglion cell spikes are recorded with an array of 512 extracellular electrodes. Array designed and built by Alan Litke’s group, UC-Santa Cruz.

  5. Example STAs spatial component temporal component ON OFF parasol contrast midget time before spike (msec)

  6. Stimulus

  7. Example STA In order to compare many cells, each STA is parameterized by fitting a model.

  8. RFs of all cells

  9. Classification

  10. Functional Characterization of Parasols and Midgets What is the relationship between RF and DF? How does the coverage of parasol and midget RFs differ? Are the ON-OFF asymmetries of parasols also found in midgets?

  11. Parasols have more DF overlap than midgets Parasol Dendritescoverage of ~3-4 Midget Dendritescoverage of 1 Dacey & Brace (1992), Dacey (1993) Does DF coverage predict RF coverage? Is RF coverage different for parasols and midgets?

  12. Parasol and midget RFs seem to have the same coverage What is the relationship between DF and RF?

  13. Mapping RF onto DF Parasol and midget RF diameters taken from5,643 cells in 18 preparations. diameter (um) eccentricity (mm, temp. eq.) Horizontal bars indicate eccentricity measurement error.Vertical bars indicate s.d. of RF diameter within one retina.DF diameters from Watanabe & Rodieck 1989.

  14. Interpretation By what mechanism are parasol RFs relatively shrunk? • More inhibition on parasol’s peripheral dendrites (Grunert 1999). • Bipolars feeding parasols pool from relatively smaller area. • More attenuation of distal inputs?

  15. different for each Functional Characterization of Parasols and Midgets What is the relationship between RF and DF? How does the coverage of parasol and midget RFs differ? Are the ON-OFF asymmetries of parasols also found in midgets?

  16. Parasol & midget mosaics

  17. Parasol & midget mosaics

  18. Is coverage really the same?a parametric test normalized nearest neighbor distance:distance from center to center divided by cell size

  19. Is coverage really the same?a non-parametric test

  20. Is coverage really the same?a non-parametric test # pixels covered by exactly 1 cell threshold relative to peak

  21. Interpretation Higher parasol DF coverage and shrunken RF perfectly compensate to give same coverage as midget, suggesting this coverage factor is the “aim” of development.

  22. same Functional Characterization of Parasols and Midgets What is the relationship between RF and DF? different for each How does the coverage of parasol and midget RFs differ? Are the ON-OFF asymmetries of parasols also found in midgets?

  23. ON-OFF Asymmetries RF diameter (um) time to peak response (msec) Data taken from 5643 cells from 18 retinas.Bars indicate standard deviation within one retina.

  24. Interpretation Similarity of ON and OFF asymmetries for parasol and midgets suggest they arise prior to ganglion cell processing

  25. yes size speed Functional Characterization of Parasols and Midgets What is the relationship between RF and DF? different for each How does the coverage of parasol and midget RFs differ? same Are the ON-OFF asymmetries of parasols also found in midgets?

  26. Control for pixel size

  27. Parasol-Midget relationship size (um) time to peak response (msec)

  28. Functional Characterization of Parasols and Midgets • Parasol dendrites have much more overlap than midget dendrites. Does dendritic field (DF) overlap predict receptive field (RF) overlap? • What is the relationship between RF and DF size in parasols? Is it the same for midgets? • Parasols have ON-OFF asymmetries: ON-parasols are larger and faster and OFF-parasols. Do the same asymmetries hold for ON- and OFF-midgets?

  29. Conclusions • Relationship between RF and DF is different for parasols and midgets • Parasols and midgets have same RF coverage • Parasols and midgets have same ON-OFF asymmetries

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