Rearing conditions affect neuron morphology in a telencephalic area of the zebra finch

The morphology of ANC (Archi-neostriatum caudale) neurons in zebra finches is affected by arousal and rearing conditions. Branching index and spine density of ANC neurons are decreased in isolated birds and enhanced in cage reared animals, compared to aviary reared animals. Chasing the birds around the cage, or seven days of social contact with a female, raises these indices in birds isolated until adulthood relative to those of the aviary reared animals. We conclude that branching index and spine density of ANC neurons are determined during development by the amount of social contact, arousal, and activation of ANC. The changes observed after short term treatments in adult bird may depend on the same factors.