McKenzie Tammy L B, Hernandez Alexandra M, MacDougall-Shackleton Scott A
Department of Psychology, University of Western Ontario, London, Ont., Canada.
Neurobiol Learn Mem. 2006 Nov;86(3):330-5. doi: 10.1016/j.nlm.2006.05.002. Epub 2006 Jun 27.
Male songbirds learn to produce song within a limited phase early in life; however they continue to learn to recognize songs in adulthood. Studies looking at Zenk activation after exposure to songs learned early in life for song production and songs learned in adulthood show opposite patterns of activation, suggesting distinct neural mechanisms may be involved in these two forms of learning. In this study, we look at IEG Zenk activation in auditory regions NCM and CMM of song sparrows (Melospiza melodia) to see whether recent exposure to song in adulthood leads to greater or decreased Zenk activation upon hearing that song versus a novel song. We found significantly lower activation in birds exposed to previously heard songs versus novel songs in vNCM but not dNCM, though further analysis suggest an overall trend in NCM. We found no significant difference in the amount of activation to previously heard songs vs. novel songs in CMM. These results support previous findings suggesting that activation is reduced to learned stimuli; we discuss possible implications of these findings in relation to song production learning early in life and song recognition learning in adulthood.
雄性鸣禽在生命早期的有限阶段学会发出鸣叫；然而，它们在成年后仍继续学习识别鸣叫。研究观察了在生命早期为学习鸣叫而接触的鸣叫以及成年后学习的鸣叫后Zenk的激活情况，结果显示出相反的激活模式，这表明这两种学习形式可能涉及不同的神经机制。在本研究中，我们观察了歌雀（Melospiza melodia）听觉区域NCM和CMM中即刻早期基因Zenk的激活情况，以探究成年后近期接触鸣叫是否会导致在听到该鸣叫与新鸣叫时Zenk激活增加或减少。我们发现，在腹侧NCM（vNCM）中，接触过先前听到的鸣叫的鸟类与接触新鸣叫的鸟类相比，激活显著降低，但背侧NCM（dNCM）中没有，不过进一步分析表明NCM存在总体趋势。我们发现，在CMM中，对先前听到的鸣叫与新鸣叫的激活量没有显著差异。这些结果支持了先前的研究发现，即对已学习刺激的激活会减少；我们讨论了这些发现与生命早期鸣叫产生学习以及成年后鸣叫识别学习相关的可能影响。
