Central Projection Of Different Morphological Types Of Retinal Ganglion Cells In The Chick And Their Development

Central Projection of Different Morphological Types of Retinal Ganglion Cells in the Chick and their DevelopmentThe different light information was transmitted to the visual centra and can control the organic metabolism and productive performance. Using the method of immunohistochemistry and the retrograde labeling of DiI, the visual centra projection and development of RGCs (i. e. the optic tectum, thalamus and hypothalamus) in chicks were studied in our experiments. Labeled RGCs were analyzed morphologically and classified into four major groups and six subgroups. Group I cells (66.4%)had a small somal area (73.6um2 on average) and narrow dendritic field (11304.29±7478.07um2). According to the dendritic branching pattern, they contained 2 subgroups: Is (simplicity) and Ic (complexity). Subgroup Is Cells had few branches and simple dendritic trees. Subgroup Ic cells had four to five major dendrites. These dentrites emitted many much smaller branches and complicated dendritic trees. Group II cells (15.4%) had a middle sized somal area (118.3u/m2) and middle-sized dendritic field (51682.1±12510.1um2). They contained 2 subgroups: IIs and IIc. Subgroup IIs cells had three to five major dendrites, cells had simple dendritic trees. Subgroup IIc dendrictic trees had complicated branches. Group HI cells ( 14.55% ) had a middle-sized somal area ( 231.56um2, on average ) and wide dendritic field (169328.86±45753.03um2 ). The branches of the Group III cells are simple. Three to four smooth major dendritics which came from soma formed wide dendritic field. Group IV cells (3.64%) had a large somal area (434.03um2) and wide dendritic field. Group IV cells were oval and the somal area was wide. The soma emitted 4 major dendrities. The secondary branches were closed to the somas and branched constantly and formed complicated dendritic trees. Different morphological types of retina ganglion cell projected to different central. Group I cells, Group II cells and Group IV cells projected to optic tectum. Group I cells, Group II cells, Group III cells and Group IV cells projected to thalamus and hypothalamus. Group III cells which projecting to hypothalamus transmitted light information and affected hypothalamus which controlled organic circadian. The development of Substance P immunoreactive neurons in the retinas of chick embryo were investigated by immunohistochemistry method . SP neurons were first detected in the ganglion cell layer in the chick embryo(E10).