#Retina layers series
Light initiates the conversion of rhodopsin to retinal and opsin through a series of metarhodopsin intermediates. The output neurons of the INL – the ganglion cells – carry the visual message to the rest of the brain some ganglion cell responses reflect more OPL processing, others IPL processing.įigure 2: Scheme of the sequence of events that occurs following the absorption of a quantum of light by the rod visual pigment, rhodopsin. Many cells receiving input in the IPL respond with transient responses and are highly sensitive to moving stimuli. The inner plexiform layer (IPL) is concerned more with the temporal and complex aspects of visual stimuli. The output neurons of the OPL, the ON- and OFF-bipolar cells demonstrate a center-surround antagonistic receptive field organization. The outer plexiform layer (OPL) separates visual information into ON- and OFF-channels and carries out a spatial type analysis on the visual input. Virtually all retinal synapses are found in the plexiform layers, and all visual information passes across at least two synapses, one in the outer plexiform layer and another in the inner plexiform layer, before leaving the eye.Īnalysis of the visual image occurs in both plexiform layers. The neurons are organized into three cellular (nuclear) layers which are separated by two synaptic (plexiform layers). In addition to the light-sensitive photoreceptor cells – the rods and cones - the retina contains four basic classes of neurons – horizontal, bipolar, amacrine and ganglion cells – along with one major type of glial cell – the Müller cell. It is part of the brain (central nervous system) displaced into the eye during development. The retina is a thin (~0.25 mm) layer of neural tissue that lines the back of the eye. Light, focused by the cornea and lens, passes through the retina to be captured by the photoreceptors. The axons of the ganglion cells run along the surface of the retina and form the optic nerve which carries the visual message to other parts of the brain.
Figure 1: The retina (right) consisting of photoreceptors, second-order horizontal, bipolar and amacrine cells and third- order ganglion cells, lines the back of the eye (left).
0 kommentar(er)
