Tsoi Shuk C, Aiya Utsav V, Wasner Kobi D, Phan Mimi L, Pytte Carolyn L, Vicario David S
Biology Department, The Graduate Center, City University of New York, New York, New York, United States of America.
Psychology Department, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America.
PLoS One. 2014 Sep 24;9(9):e108929. doi: 10.1371/journal.pone.0108929. eCollection 2014.
Many brain regions exhibit lateral differences in structure and function, and also incorporate new neurons in adulthood, thought to function in learning and in the formation of new memories. However, the contribution of new neurons to hemispheric differences in processing is unknown. The present study combines cellular, behavioral, and physiological methods to address whether 1) new neuron incorporation differs between the brain hemispheres, and 2) the degree to which hemispheric lateralization of new neurons correlates with behavioral and physiological measures of learning and memory. The songbird provides a model system for assessing the contribution of new neurons to hemispheric specialization because songbird brain areas for vocal processing are functionally lateralized and receive a continuous influx of new neurons in adulthood. In adult male zebra finches, we quantified new neurons in the caudomedial nidopallium (NCM), a forebrain area involved in discrimination and memory for the complex vocalizations of individual conspecifics. We assessed song learning and recorded neural responses to song in NCM. We found significantly more new neurons labeled in left than in right NCM; moreover, the degree of asymmetry in new neuron numbers was correlated with the quality of song learning and strength of neuronal memory for recently heard songs. In birds with experimentally impaired song quality, the hemispheric difference in new neurons was diminished. These results suggest that new neurons may contribute to an allocation of function between the hemispheres that underlies the learning and processing of complex signals.
许多脑区在结构和功能上存在左右差异，并且在成年期会纳入新的神经元，这些新神经元被认为在学习和新记忆形成中发挥作用。然而，新神经元对半球加工差异的贡献尚不清楚。本研究结合细胞、行为和生理学方法，以探讨：1）新神经元的纳入在大脑半球之间是否存在差异；2）新神经元的半球侧化程度与学习和记忆的行为及生理学指标之间的关联程度。鸣禽为评估新神经元对半球特化的贡献提供了一个模型系统，因为鸣禽用于发声处理的脑区在功能上是侧化的，并且在成年期会持续有新神经元的流入。在成年雄性斑胸草雀中，我们对尾内侧巢皮质（NCM）中的新神经元进行了量化，NCM是一个前脑区域，参与对个体同种鸟复杂发声的辨别和记忆。我们评估了鸣叫学习，并记录了NCM中对鸣叫的神经反应。我们发现，左侧NCM中标记的新神经元明显多于右侧；此外，新神经元数量的不对称程度与鸣叫学习的质量以及对近期听到的鸣叫的神经元记忆强度相关。在实验性鸣叫质量受损的鸟类中，新神经元的半球差异减小。这些结果表明，新神经元可能有助于半球之间功能的分配，这是复杂信号学习和处理的基础。
