Borelli K G, Blanchard D C, Javier L K, Defensor E B, Brandão M L, Blanchard R J
Pacific Bioscience Research Center, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, HI 96822, USA.
Neuroscience. 2009 Sep 15;162(4):914-23. doi: 10.1016/j.neuroscience.2009.05.047. Epub 2009 May 27.
Mice show urinary scent marking behavior as a form of social communication. Marking to a conspecific stimulus mouse or odor varies with stimulus familiarity, indicating discrimination of novel and familiar animals. This study investigated Fos immunoreactivity in inbred C57BL/6J (C57) males following scent marking behavior in response to detection of a social stimulus, or discrimination between a familiar and an unfamiliar conspecific. In Experiment 1 C57 mice were exposed for four daily trials to an empty chamber; on a test day they were exposed to the same chamber or to a male CD-1 mouse in that chamber. Increased scent marking to the CD-1 mouse was associated with increased Fos-immunoreactive cells in the basolateral amygdala, medial amygdala, and dorsal and ventral premammillary nuclei. In Experiment 2 C57 mice were habituated to a CD-1 male for 4 consecutive days and, on the 5th day, exposed to the same CD-1 male, or to a novel CD-1 male. Mice exposed to a novel CD-1 displayed a significant increase in scent marking compared to their last exposure to the familiar stimulus, indicating discrimination of the novelty of this social stimulus. Marking to the novel stimulus was associated with enhanced activation of several telencephalic, as well as hypothalamic and midbrain, structures in which activation had not been seen in the detection paradigm (Experiment 1). These included medial prefrontal and piriform cortices, and lateral septum; the paraventricular nuclei, ventromedial nuclei, and lateral area of the hypothalamus, and the ventrolateral column of the periaqueductal gray. These data suggest that a circumscribed group of structures largely concerned with olfaction is involved in detection of a conspecific olfactory stimulus, whereas discrimination of a novel vs. a familiar conspecific stimulus engages a wider range of forebrain structures encompassing higher-order processes and potentially providing an interface between cognitions and emotions.
小鼠表现出尿液气味标记行为，作为一种社会交流形式。对同种刺激小鼠或气味的标记会因刺激的熟悉程度而有所不同，这表明对新奇和熟悉动物具有辨别能力。本研究调查了近交系C57BL/6J（C57）雄性小鼠在对社会刺激进行气味标记行为后的Fos免疫反应性，或对熟悉和不熟悉同种动物的辨别。在实验1中，C57小鼠每天在一个空实验箱中进行四次试验；在测试日，它们被置于同一个实验箱中，或与一只雄性CD-1小鼠共处一室。对CD-1小鼠气味标记的增加与基底外侧杏仁核、内侧杏仁核以及背侧和腹侧乳头前核中Fos免疫反应性细胞的增加有关。在实验2中，C57小鼠连续4天适应一只CD-1雄性小鼠，在第5天，将其暴露于同一只CD-1雄性小鼠，或一只陌生的CD-1雄性小鼠面前。与最后一次暴露于熟悉刺激相比，暴露于陌生CD-1小鼠的小鼠气味标记显著增加，这表明对这种社会刺激的新奇性具有辨别能力。对新奇刺激的标记与几个端脑以及下丘脑和中脑结构的激活增强有关，而在检测范式（实验1）中未观察到这些结构的激活。这些结构包括内侧前额叶皮质和梨状皮质以及外侧隔；下丘脑室旁核、腹内侧核和外侧区，以及导水管周围灰质的腹外侧柱。这些数据表明，一组主要与嗅觉相关的特定结构参与了同种嗅觉刺激的检测，而对新奇与熟悉同种刺激的辨别涉及更广泛的前脑结构，包括高阶过程，并可能提供认知与情感之间的接口。
