Diversity of LGN-Projecting Primate Retinal Ganglion Cells and Their Contributions to Visual Perception

The visual system's complexity and richness are fundamental to human experience. Underscoring this complexity is a network of diverse cells working in concert to generate coherent visual experience. Despite years of progress in understanding the functional significance of this heterogeneity, many aspects of the intricate workings of the visual system remain enigmatic. This review focuses on the various classes of retinal ganglion cells (RGCs), their receptive fields (RFs), and their role in conscious vision, particularly within the primate visual system. By examining the anatomy and physiology of RGCs and their central projections, particularly to the dorsal lateral geniculate nucleus (LGN), this paper aims to elucidate the contributions of the different RGC types to visual perception. The visual system's complexity and richness are fundamental to human experience. Retinal ganglion cells (RGCs), a diverse population of neurons that form the output layer of the retina, encode distinct aspects of visual information provided to the brain, thereby supporting the translation of the visual scene at the retina to visual perception in the cortex. This review explores the anatomical and functional diversity of RGC types, emphasizing their receptive field properties and central projections, particularly to the dorsal lateral geniculate nucleus (LGN). The contributions of different RGC classes that support parallel processing of spatial resolution, color, motion, and luminance are discussed, along with non-image-forming functions. Special attention is given to low-density, koniocellular-projecting RGCs, whose varied roles are only beginning to be understood. By integrating recent advances in anatomy, physiology, and connectivity, this review underscores how a comprehensive understanding of RGC diversity is critical for unraveling visual processing and informing future approaches to visual restoration and prosthetic development.