Applying Super-Resolution and Tomography Concepts to Identify Receptive Field Subunits in the Retina
Fig 8
Experimental application of STR.
(A) Autocorrelation functions, receptive fields (RFs) displayed as 1.5 σ ellipses of Gaussian fits (one distant cell not included), temporal STAs (normalized to unit Euclidean norm), and nonlinearities (scaled to equal maximum) of all identified Off (top) and On (bottom) parasol cells. (B) Excerpt of a sample stimulus projected onto the retina during a flash. (C) Unprocessed sinogram of a sample Off parasol cell. (D) Same sinogram as in (C), but processed by correcting for the receptive field position and applying a Gaussian filter. (E) Overview of the results of four sample cells. Left column depicts spatial STAs, middle column illustrates PSTHs (yellow background designates presentation of the Ricker stripes), right column shows reconstructions from the processed sinograms via FBP. Red colors in reconstructions denote positive values, blue colors denote negative values. Spatial scales of STAs and reconstructions are equal, but reconstruction has higher resolution. PSTHs were computed irrespective of the angle and position of the stripes with a bin size of 10 ms. Sample cell in top row is same cell as in (C) and (D). Bottom two rows contain the results of an analysis of the offset responses of cells. (F) Reconstructions of the sample Off parasol cell from the top row of (E) from separate analyses of the first and second halves of the measurement. (G) Same as (F), but for the On parasol cell from (E). (H) Distribution of the number of hotspots identified in the reconstructions across all recorded Off and On parasol ganglion cells. Colored ticks at the bottom mark the medians for the two cell types. (I) Distribution of the average distance of a hotspot to its nearest neighbor in each ganglion cell’s reconstruction. Ticks at bottom mark the medians.