Origins of direction selectivity in the primate retina

From mouse to primate, there is a striking discontinuity in our current understanding of the neural coding of motion direction. In non-primate mammals, directionally selective cell types and circuits are a signature feature of the retina, situated at the earliest stage of the visual process. In primates, by contrast, direction selectivity is a hallmark of motion processing areas in visual cortex, but has not been found in the retina, despite significant effort. Here we combined functional recordings of light-evoked responses and connectomic reconstruction to identify diverse direction-selective cell types in the macaque monkey retina with distinctive physiological properties and synaptic motifs. This circuitry includes an ON-OFF ganglion cell type, a spiking, ON-OFF polyaxonal amacrine cell and the starburst amacrine cell, all of which show direction selectivity. Moreover, we discovered that macaque starburst cells possess a strong, non-GABAergic, antagonistic surround mediated by input from excitatory bipolar cells that is critical for the generation of radial motion sensitivity in these cells. Our findings open a door to investigation of a precortical circuitry that computes motion direction in the primate visual system.This work was largely supported by grants from the National Eye Institute (NIH NEI) to D.M.D. (EY032045), R.G.S. (EY022070), P.D.G. (EY018369) and by National Institutes of Health (NIH) Grant RR-00166 to the Tissue Distribution Program of the Washington National Primate Research Center (WaNPRC), grant P51 OD010425 from the NIH Office of Research Infrastructure Program to the WaNPRC. and EY01730 to the Vision Research Core at the University of Washington. Additional support from MICINN Programa de Movilidad Salvador de Madariaga (PRX16/00188) to F.V. and NIH (NIBIB) R21EB028069 to J.B.T, and a Christina Enroth-Cugell and David Cugell Fellowship to J.W.Peer reviewe

Center Surround Receptive Field Structure Of Cone Bipolar Cells In Primate Retina

In non-mammalian vertebrates, retinal bipolar cells show center-surround receptive field organization. In mammals, recordings from bipolar cells are rare and have not revealed a clear surround. Here we report center-surround receptive fields of identified cone bipolar cells in the macaque monkey retina. In the peripheral retina, cone bipolar cell nuclei were labeled in vitro with diamidino-phenylindole (DAPI), targeted for recording under microscopic control, and anatomically identified by intracellular staining. Identified cells included `diffuse' bipolar cells, which contact multiple cones, and `midget' bipolar cells, which contact a single cone. Responses to flickering spots and annuli revealed a clear surround: both hyperpolarizing (OFF) and depolarizing (ON) cells responded with reversed polarity to annular stimuli. Center and surround dimensions were calculated for 12 bipolar cells from the spatial frequency response to drifting, sinusoidal luminance modulated gratings. The frequency response was bandpass and well fit by a difference of Gaussians receptive field model. Center diameters were all two to three times larger than known dendritic tree diameters for both diffuse and midget bipolar cells in the retinal periphery. In one instance intracellular staining revealed tracer spread between a recorded cell and its nearest neighbors, suggesting that homotypic electrical coupling may contribute to receptive field center size. Surrounds were around ten times larger in diameter than centers and in most cases the ratio of center to surround strength was #1. We suggest that the center-surround receptive fields of the major primate ganglion cell types are established at the bipolar cell, probably by the circuitry of the outer retina. 2000 Elsevier Science Ltd. All rights..

Characterization and Use of a Digital Light Projector for Vision Research

For creating stimuli in the laboratory, digital light projection (DLP) technology has the potential to overcome the low output luminance, lack of pixel independence, and limited chromaticity gamut of the cathode ray tube (CRT). We built a DLP-based stimulator for projecting patterns on the in vitro primate retina. The DLP produces high light levels and has good contrast. Spatial performance was similar to that of a CRT. Temporal performance was limited by the refresh rate (63 Hz). The chromatic gamut was modestly larger than that of a CRT although the primary spectra varied to a small degree with light output and numerical aperture. 2001 Elsevier Science Ltd. All rights reserved

Supplementary document for Microconnectomics reveals human retinal mitochondria that align with reflective bands in optical coherence tomography - 6582431.pdf

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Supplementary document for Microconnectomics reveals human retinal mitochondria that align with reflective bands in optical coherence tomography - 6585805.pdf

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