Stratification and square pattern arrangements in the dorsal inner plexiform layer in the retina of Callionymus lyra...

The dorsal inner plexiform layer in the retina of Callionymus lyra consists of successive fibrous F layers and geometrically organized P layers. In the F layers no pattern arrangement of the bipolar synaptic buttons was observed. In the P layers, on the contrary, the bipolar synaptic buttons are grouped by three distinct square patterns. The alpha pattern measures 5 micron and corresponds to the square pattern of the photoreceptor cells. The beta and the gamma pattern measure 7 micron. One of both patterns corresponds to the single cone arrangement, while the other coincides with the crossings of the rows of double cone pairs. The alternation of F and P layers results in the stratified appearance of the inner plexiform layer.