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An overview of the history of receptive field mapping of mammalian retinal ganglion cells. The receptive field concept is described, along with how this concept has been applied to retinal ganglion cells. A brief description of different types of retinal ganglion cell receptive field is given and an outline provided of widely accepted receptive field models. The various terminologies in use for naming different classes of retinal ganglion cell and their receptive field structures is discussed and a summary of where this field of research stands now is presented.

The inner retina of fishes, as in all other vertebrates, carries visual information from the photoreceptors to the axons projecting to the central brain, and also does considerable processing of that information. This processing emphasizes changes in time, space, and color, and thus reduces the number of channels (axons of the optic nerve) necessary to convey information to the brain. Principles common to most vertebrate retinas are present in fish retinas. This article reviews the major cells between receptors and ganglion cells, emphasizing the ganglion cells and the spike trains they transmit to the brain.

Information about the visual environment leaves the retina in parallel streams, carried to the brain by the axons of different types of retinal ganglion cells. Each ganglion cell type is activated by certain visual features. The retinal circuitry leading up to the ganglion cells, combined with properties of the ganglion cells themselves, extracts those features from the incident stimulus. This is achieved by sophisticated networks of excitatory and inhibitory interneurons, which are connected to each other in an appropriate spatial relationship, and which have suitable temporal properties. The circuits of movement-encoding ganglion cells are described and compared in greater detail.

An overview of the history of receptive field mapping of mammalian retinal ganglion cells is given in this article. The receptive field concept is described, along with how this concept has been applied to retinal ganglion cells. A brief description of different types of retinal ganglion cell receptive fields is given and an outline provided of widely accepted receptive field models. The various terminologies in use for naming different classes of retinal ganglion cells and their receptive field structures is discussed, and a summary of the current state of this field of research is presented.

This article provides a brief review of the morphology, synaptic inputs, distribution, and central projections of retinal ganglion cells, with the emphasis on studies on primates. Midget cells project to the parvocellular layers of the lateral geniculate nucleus (LGN) and mediate both red–green color vision and high-acuity form vision. Parasol cells project to the magnocellular layers of the LGN and contribute to many aspects of vision, particularly to the perception of motion. Small bistratified cells project to the koniocellular layers of the LGN and mediate blue–yellow color vision. Primates also have the same types of retinal ganglion cells as other mammals.

Ganglion cells are the only retinal neurons communicating directly with the brain. It is well known that mammalian ganglion cells comprise more than a dozen types, clearly distinguishable from one another in structure and function. Each type also appears to send axons to a distinctive subset of the many central visual nuclei receiving direct retinal input. The implication is that each ganglion cell type forms a specialized channel sculpted by evolutionary pressures to fulfill specific visual functions. Though the outlines of this perspective have been clear for decades, many essential details are lacking. The goal of this chapter is to summarize the state of knowledge about where retinal axons are distributed in the brain and which types of ganglion cells contribute to these pathways. The primary focus is on ganglion cell types that appear to be conserved across mammalian phylogeny.

The distribution of sensitivity in a ganglion cell's receptive field is approximately the convolution of the bipolar receptive field with a weighting function that is as wide as the dendritic tree. A large dendritic arbor enlarges the ganglion cell’s receptive field and imposes irregularities in the distribution of sensitivity across this field. A small dendritic arbor allows the bipolar cell to set the size of the ganglion cell receptive field and to smooth the distribution of sensitivity. Stochastic properties of the bipolar cell array, as well as adaptation in this array, contribute to these irregularities. Bipolar cells, by their synaptic receptors and other intrinsic properties, initiate temporal frequency channels. Bipolar cells contribute to information encoding by the ganglion cell’s spike train by releasing glutamate in bursts and with good temporal accuracy.

Publisher Summary This chapter summarizes the characteristics of cat ganglion cells that are vulnerable and those that appear to be largely insensitive to the cortical lesion. It reviews the relevant features of retinal ganglion structure, function, contributions to vision, and connectivity and also describes the impact of primary visual cortex lesions on ganglion cells and visually guided behavior. The elimination of β (X) cells has a potentially profound impact on visual processing in addition to the absence of primary visual cortex. The three most significant factors linked to the survival, and death of cat retinal ganglion cells following lesions of primary visual cortex are maturational status, patterns of connectivity, and rate of degeneration of lateral geniculate nucleus (LGN) neurons. β (X)-retinal ganglion cells in the cat and monkey, and by extension humans, have a unique and a signature array of morphological, physiological, and connectional characteristics that set them apart from all other ganglion cell types. They are also extremely fragile and depend for survival on primary visual cortex and its intermediate relay structure, the LGN, both some distance apart.

Retinal neurons with distinct dendritic morphologies are likely to comprise different cell types, subject to three important caveats. First, it is necessary to avoid creating “artificial” cell types based on arbitrary criteria—for example, the presence of two or three primary dendrites. Second, it is essential to take into account changes in morphology with retinal eccentricity and cell density. Third, the retina contains imperfections like any natural system and a significant number of retinal neurons display aberrant morphologies or make aberrant connections that are not typical of the population as a whole. Many types of retinal ganglion cells show diverse patterns of tracer coupling, with the simplest pattern represented by the homologous coupling shown by On-Off direction-selective (DS) ganglion cells in the rabbit retina. Neighboring DS ganglion cells with a common preferred direction have regularly spaced somata and territorial dendritic fields, whereas DS ganglion cells with different preferred directions may have closely spaced somata and overlapping dendritic fields.

A knowledge of the dynamics (temporal properties) of neuronal populations is essential for an understanding of their function, and is also crucial when one attempts to develop computational or mathematical models of the neurons. Here we review the temporal properties of the receptive fields (RFs) of the two best-studied types of ganglion cells in the primate retina, those that project to the parvocellular (P) and magnocellular (M) layers of the dorsal lateral geniculate nucleus. The center and surround mechanisms of the P RFs are approximately linear, and their impulse responses are very similar, although the surround lags the center by a few milliseconds. The center and surround are chromatically opponent. With the appropriate stimulus, one can find significant nonlinearities in their responses, and also in the interaction between the center and surround. The phase lag between the responses of the center and surround depends on the temporal frequency, so that at high temporal frequency the antagonism between them is reduced or abolished. The temporal responses of M cells are nonlinear, and with increasing contrast they show the effects of a contrast gain control. The different dynamical properties of the two populations suggest that M cells participate in motion analysis, while P cells are used for the analysis of form, texture, and perhaps color.

Publisher Summary This chapter discusses the two sets of channels that originate in the mammalian retina, the ON and OFF systems and the midget and parasol system. The midget and parasol systems of the primate retina come in ON and OFF subvarieties. The midget system has also been called the color-opponent or the parvocellular channel and the parasol system has also been called the broad-band or magnocellular channel. The receptive fields of the midget system, as the name implies, are quite small. In central retina, the receptive field center is typically made up of a single cone. As a consequence, the midget cells are color coded. Midget cells come in several subvarieties that include red ON- and OFF-center; green ON- and OFF-center; and blue ON-center. Blue OFF-center cells are rare. In contrast to the arrangement for the midget cells, the receptive fields of parasol cells are much larger and generally, there is no clear differential input from the three cone types to either the center or the surround regions of these cells.

Publisher Summary This chapter explains the response properties of dissociated ganglion cells to constant current stimulation. The whole-cell patch clamp recording technique offers a powerful tool for assessing the membrane properties of developing neurons. This method to record from acutely dissociated retinal ganglion cells obtained from postnatal and prenatal cats, in order to characterize the development of spiking properties in these neurons. The long-term goal of this work is to relate the functional development of retinal ganglion cells to the structural refinements that are known to occur in these neurons during ontogeny. It has been found recently that somatostatin-containing amacrine cells and ganglion cells, which at maturity are preferentially distributed in the inferior, are widespread in the fetal cat retina. It is conceivable that developing ganglion cells are particularly sensitive to certain transiently expressed neuromodulators, and that this contributes to the correlated discharges that have been noted in the developing retina.

Publisher Summary This chapter highlights the development of ideas on the functional organization of retinal ganglion cells. Kuffler (1952) was the first to provide the detailed maps of the receptive fields of cat ganglion cells. The maps turned out to be composite and unlike those obtained by Hartline in the frog. A roughly circular central patch having one kind of sensitivity was surrounded by a concentric annular region of opposite sensitivity. The two kinds of sensitivity were (1) increase in discharge when light was turned on (on-type) and (2) increase in discharge when light was turned off (off-type). Two general classes of ganglion cells were distinguished: (1) on-centre off-surround, and (2) off-centre on-surround. Kuffler's receptive field map shows some overlap of on and off regions that produced an intermediate annular zone, where a small flash spot produced both on and off responses. The next major development in the classification of retinal ganglion cells came from the testing of ganglion cells with sinusoidal grating patterns. This resulted in the classification of ganglion cells into X cells and Y cells..

This chapter describes the relationship the dendritic tree of a cat ganglion cell and the response of the cell to a small spot of light within the receptive field. Between receptors and ganglion cells, there is a complex network of interneurons and a distribution of synaptic contacts. The function of the network may be presumed to involve a separation of stimulus classes, such as contrast, oriented boundaries, or movement in a particular direction. The network comes into play in processes such as light and dark adaptation. There is no indication, however, that a bipolar cell, for example, may have a synaptic input to a ganglion cell with a transmitter action depending on the distance of the synapse from the ganglion cell soma. The chapter discusses the dendritic tree of the ganglion cell.