Functional connectivity in the retina at the resolution of photoreceptors

Abstract

To understand a neural circuit requires knowing its connectivity. This paper reports measurements of functional connectivity between the input and ouput layers of the retina at single cell resolution and its implications for color vision. Multi-electrode technology was employed to record simultaneously from complete populations of the retinal ganglion cell types (midget, parasol, small bistratified) that transmit high-resolution visual signals to the brain. Fine-grained visual stimulation was used to identify the location, type and strength of the functional input of each cone photoreceptor to each ganglion cell. The populations of ON and OFF midget and parasol cells each sampled the complete population of long and middle wavelength sensitive cones. However, only OFF midget cells frequently received strong input from short wavelength sensitive cones. ON and OFF midget cells exhibited a small non-random tendency to selectively sample from either long or middle wavelength sensitive cones, to a degree not explained by clumping in the cone mosaic. These measurements reveal computations in a neural circuit at the elementary resolution of individual neurons.Color vision requires neural circuitry to compare signals from spectrally distinct cone types. For example, the signature of primate color vision -red-green and blue-yellow color opponency -implies that neural circuits pit signals from different cone types against one another. However, the pattern of connectivity between the (L)ong, (M)iddle, and (S)hort Users may view, print, copy, download and text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: http://www.nature.com/authors/editorial_policies/license.html#terms Contact: E.J. Chichilnisky, Systems Neurobiology, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA. ej@salk.edu, phone: (858) 453-4100 x1286. * Equal contributionsAuthor Contributions: G.D.F., J.L.G., A.S., and E.J.C. conceived the experiments. G.D.F., J.L.G., A.S., M.G., J.S., and E.J.C. performed the electrophysiological experiments. G.D.F, J.L.G., A.S., M.G., T.A.M., and L.P., analyzed the data. A.S., D.E.G., K.M., W.D., A.M.L. provided and supported the large-scale multielectrode array system. G.D.F. and E.J.C. wrote the manuscript. To resolve the fine structure of RFs, stimuli with 10-fold smaller pixels (5×5 μm) were used. At this resolution, RFs did not conform to the smooth Gaussian approximation used in Fig. 1a (center) and in previous studies 18 . Instead, each RF was composed of punctate islands of light sensitivity (Fig. 1a, flanking). The separation between islands was roughly equal to the spacing of the cone lattice, consistent with the idea that each island reflected the contribution of a single cone 10 , 19 . To test this hypothesis, locations of islands were compared to photographs of cone outer segments labeled with peanut agglutinin; a close alignment was observed (Fig. 1b, see Supplementary Methods). HHS Public AccessTh...

FREAK: Fast Retina Keypoint

“…Surprisingly, SIFT is the worst descriptor in the first testing environment (8) similar to what has been shown in BRISK [16]. SIFT extracts several descriptors when the estimated orientation has multiple good candidates.…”

“…Neuroscience has made lots of progress in understanding the visual system and how images are transmitted to the brain [8]. It is believed that the human retina extracts details from images using Difference of Gaussians (DoG) of various sizes and encodes such differences with action potentials.…”

Challenges in Retinal Circuit Regeneration

“…178) In addition, extracellular multi-electrode recordings from hundreds of RGC with fine-grained white-noise stimulation allows mapping of RGC inputs from individual cone photoreceptors. 179) Intriguingly, tissue-clearing methodologies such as SCALE, CLARITY, SeeDB, CUBIC, and PACT have rendered the whole brain optically transparent, permitting circuit-and organ-wide mapping at cellular and subcellular resolution by endogenous expression of fluorescent proteins and post hoc detection of DNA, RNA, and peptides. [180][181][182][183][184] A mechanistic understanding of retinal regeneration will be necessary in order to develop new strategies for circuit reconstruction and vision restoration.…”

So many pieces, one puzzle: cell type specification and visual circuitry in flies and mice

“…3B). Indeed, mosaic spacing is one of the fundamental units defining cell types in the retina (Field and Chichilnisky 2007;Field et al 2010) and is often related to dendritic tiling or the extent to which the dendrites of retinal cell types avoid one another or overlap (Fig. 3E).…”