Christina Enroth-Cugell

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SUMMARY 1. Spatial summation within cat retinal receptive fields was studied by recording from optic-tract fibres the responses of ganglion cells to grating patterns whose luminance perpendicular to the bars varied sinusoidally about the mean level. 2. Summation over the receptive fields of some cells (X-cells) was found to be approximately linear, while(More)
The contrast sensitivity to gratings drifting at 2.0 Hz has been measured for X and Y type retinal ganglion cells, and these data have been used to characterize the sizes and peak sensitivities of centers and surrounds. The assumption of Gaussian sensitivity distributions is adequate for both types of cells, but allows a better description of X than of Y(More)
Spatiotemporal frequency responses were measured at different levels of light adaptation for cat X and Y retinal ganglion cells. Stationary sinusoidal luminance gratings whose contrast was modulated sinusoidally in time or drifting gratings were used as stimuli. Under photopic illumination, when the spatial frequency was held constant at or above its(More)
It has been suggested for a number of years that ganglion cells inform the rest of the brain about contrast in the retinal image. The purpose of the work undertaken here was to demonstrate this fact explicitly. Extracellular recordings were made from X- and Y-cell axons of the optic tracts of anesthetized cats. Responses of these cells to gratings that were(More)
1. The discharges of ganglion cells in the cat's retina were recorded under conditions intended to isolate the cone system.2. Stiles' two-colour threshold technique permitted the photopic system to be studied when at its highest sensitivity. The absolute sensitivity of a ganglion cell, expressed in equivalent photons of lambda(max) at the cornea per impulse(More)
The spatio-temporal characteristics of cat retinal ganglion cells showing linear summation have been studied by measuring both magnitude and phase of the responses of these cells to drifting or sinusoidally contrast-modulated sinusoidal grating patterns. It has been demonstrated not only that X cells behave approximately linearly when responding with(More)
The primary goal of this study was to expand the description of the filtering properties of the Y-cell receptive field, by quantitatively characterizing the spatial filtering properties of the receptive field's center-and-surround components as a function of adapting light level. A range of more than five orders of magnitude in retinal illuminance were(More)
Visual stimulation outside the classical receptive field can have pronounced effects on cat retinal ganglion cells. We characterized the effects of such stimulation by varying the contrast, spatial frequency, temporal frequency, and spatial extent of remote drifting sinusoidal gratings. We found that the mean firing rate of some X-cells and most Y-cells(More)
Many of you may wonder why anyone would spend the better part of a lifetime doing little more than recording from retinal ganglion cells, as I have done, so, I will give some justification for this a little bit later. Since John Robson has more sense than I, he has done a lot of other things than studied ganglion cells. However, the fact remains that it was(More)
1. Action potentials were recorded from single fibres in the optic tract of anaesthetized cats. 2. A sectored disk or 'windmill', concentric with the receptive field, was rotated about its centre to cause local changes in illumination throughout the receptive field without changing the total amount of light falling on the receptive field centre or surround.(More)