ASYNCHRONOUS CHANGES IN SIZE, NUMBER, AND SHAPE OF SYNAPSES IN THE DEVELOPING SUPERIOR COLLICULUS

The ultra-structural development of synapses in retino-receptive layer s of the opossum superior colliculus was studied by the ethanolic phos photungstic acid (E-PTA) method. There was a tendency for a slight red uction in the diameter of synaptic disks, a rise and fail of numerical densities and, except for an ephemeral period, a general increase in the proportion of ''frown'' among curve synapses. The lack of strict s ynchrony and the occurrence of different patterns of changes suggest t hat multiple factors contribute to synaptic maturation. (C) 1997 ISDN.