[Development of the structure and stability of Mauthner's neurons in Xenopus laevis tadpoles on the implantation of additional auditory vesicles].

The ultrastructure and functional changes of the Mauthner cells were studied in the X. laevis tadpoles under the conditions of the experimentally doubled source of their afferentation, an additional pair of ear vesicles. Additional afferent fibers grow from the receptors to the brain and form additional synapses on the soma of the Mauthner cells, indistinguishable by their morphology from the terminals of their own acoustic nerves. The altered interneuronal interactions lead, on one hand, to the accelerated maturation of the Mauthner cells and, on the other one, to the vacuolization of a part of the cytoplasm. The superafferentation of the Mauthner cells is characterized by a long-term marked decrease in the length of sections of the active zones of axosomatic synapses. It is suggested that this structural rearrangement provides for a marked increase in the stability of the Mauthner cells with respect to extreme natural stimulation which is noted in the tadpoles with the double vestibular system.