Nerve growth factor effects on the song control system of zebra finches

The aim of this experiment was to test whether or not nerve growth factor (NGF) is involved in cholinergic processes in the avian brain, by injecting NGF into the higher vocal center (HVC) and examining its effects on adult male zebra finch song. Since NGF has been hypothesized to protect cells after injury, some birds received both NGF and ibotenic acid (IBO) lesions of HVC, while others received either NGF or IBO or neither (SHAM). Only the IBO-treated birds showed alterations in song. Although there was no evidence of cell preservation in the immunocytochemical and morphological analysis NGF appears to prevent the IBO induced impairment in song augmenting the activity of the remaining neurons and enhancing brain repair.