Postnatal Development of the Feline End Bulb of Held

Abstract

Maturation of the end bulb of Held (EBH) in the anteroventral cochlear nucleus (AVCN) was studied to determine what degree of plasticity is found in a synapse undergoing maturation, at the same time that the recipient neuron is increasing in size. Although the normal development of the neurons in the cochlear nucleus has been studied by Larsen and Morest, the normal development of the EBH has not been reported at the EM level.The EBH was studied in kittens ranging in age from birth to 60 days postpartum and in adult cats using electron microscopy and Golgi preparations with light microscopy. At selected developmental ages (birth, alternate days starting at the second day of life and extending throughout the first postnatal month, and adult), serial-sectioned electron micrographs of the EBH and its recipient neuron, the large spherical cell (LSC), were traced using computer-assisted morphometry.