Type of Document	Thesis
Author	Jones, Clayton W
URN	etd-08282003-152632
Title	The Role Of Use In Neural And Behavioral Plasticity
Degree	Master of Science
Department	Psychology, Department of
Advisory Committee	Advisor Name Title Frank Johnson, PhD Committee Chair Jon S. Bailey, PhD Committee Member Michael E. Rashotte, PhD Committee Member
Keywords	Influences Of Use On Neuronal Growth
Date of Defense	2003-06-01
Availability	unrestricted
Abstract Among adult male zebra finches there is a striking two-fold variation in the morphology of several telencephalic regions that control song. The functional significance of such dramatic individual differences is presently unclear ¨C previous attempts to correlate enhanced morphology with song complexity have produced mixed results (e.g., MacDougall-Shackleton et al., 1998, Airey & DeVoogd, 2000). I have tested an alternative hypothesis, namely, that morphological differences in song regions are related to use. I tested this relationship in adult male zebra finches by selectively reducing vocal production while holding all environmental variables constant, save the timing of daily feeding. Access to food was restricted to the final 5-6h of a 14h light phase, a manipulation that attenuates daily undirected song production by two-thirds, but does not affect daily food intake or body mass (Johnson & Rashotte, 2002). Birds were initially maintained on ad lib conditions for 2mos and recorded weekly for 24h to establish baseline levels of daily undirected song production. They were then shifted to the restricted feeding protocol and held at <30% of their baseline level of daily song production for 4mos without major effect on body mass. When compared to controls that sang ¡Ö100% of their baseline (n=5),birds in the experimental group (n=5) showed reduced morphology (volume, neuron number) in a brain region involved in song control. In contrast, a measure of overall brain volume did not differ between groups. The data support the hypothesis that the morphology of the song control system is influenced by use, and set the stage for experiments to determine how use influences neuronal growth, survival and/or addition within brain regions controlling song
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