Neuroscience Program, McGill University, Montreal, QC, Canada.
Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.
Neuroscience. 2018 May 21;379:415-427. doi: 10.1016/j.neuroscience.2018.03.032. Epub 2018 Mar 28.
Distinguishing between familiar and unfamiliar individuals is an important task that shapes the expression of social behavior. As such, identifying the neural populations involved in processing and learning the sensory attributes of individuals is important for understanding mechanisms of behavior. Catecholamine-synthesizing neurons have been implicated in sensory processing, but relatively little is known about their contribution to auditory learning and processing across various vertebrate taxa. Here we investigated the extent to which immediate early gene expression in catecholaminergic circuitry reflects information about the familiarity of social signals and predicts immediate early gene expression in sensory processing areas in songbirds. We found that male zebra finches readily learned to differentiate between familiar and unfamiliar acoustic signals ('songs') and that playback of familiar songs led to fewer catecholaminergic neurons in the locus coeruleus (but not in the ventral tegmental area, substantia nigra, or periaqueductal gray) expressing the immediate early gene, EGR-1, than playback of unfamiliar songs. The pattern of EGR-1 expression in the locus coeruleus was similar to that observed in two auditory processing areas implicated in auditory learning and memory, namely the caudomedial nidopallium (NCM) and the caudal medial mesopallium (CMM), suggesting a contribution of catecholamines to sensory processing. Consistent with this, the pattern of catecholaminergic innervation onto auditory neurons co-varied with the degree to which song playback affected the relative intensity of EGR-1 expression. Together, our data support the contention that catecholamines like norepinephrine contribute to social recognition and the processing of social information.
区分熟悉和不熟悉的个体是一种重要的任务，它影响着社交行为的表达。因此，识别参与处理和学习个体感觉属性的神经群体对于理解行为机制非常重要。儿茶酚胺合成神经元参与感觉处理，但相对而言，它们对各种脊椎动物类群的听觉学习和处理的贡献知之甚少。在这里，我们研究了儿茶酚胺能电路中的即时早期基因表达在多大程度上反映了社交信号的熟悉程度的信息，并预测了鸣禽中感觉处理区域的即时早期基因表达。我们发现，雄性斑马雀很容易学会区分熟悉和不熟悉的声音信号（“歌曲”），并且熟悉歌曲的播放导致蓝斑（但不是腹侧被盖区、黑质或导水管周围灰质）中表达即时早期基因 EGR-1 的儿茶酚胺能神经元比播放不熟悉歌曲的要少。蓝斑中 EGR-1 的表达模式与在两个听觉学习和记忆中涉及的听觉处理区域相似，即尾侧中脑背核（NCM）和尾侧中脑间质（CMM），这表明儿茶酚胺对感觉处理有贡献。与这一观点一致的是，儿茶酚胺能神经支配听觉神经元的模式与歌曲播放影响 EGR-1 表达相对强度的程度一致。总之，我们的数据支持这样一种观点，即去甲肾上腺素等儿茶酚胺有助于社会识别和社会信息的处理。
