Di Lorenzo Patricia M, Platt Daniel, Victor Jonathan D
Department of Psychology, Binghamton University, Binghamton, New York 13902-6000, USA.
Ann N Y Acad Sci. 2009 Jul;1170:365-71. doi: 10.1111/j.1749-6632.2009.03903.x.
As the second synapse in the central gustatory pathway of the rodent, the parabrachial nucleus of the pons (PbN) receives information about taste stimuli directly from the nucleus of the solitary tract (NTS). Data show that NTS cells amplify taste responses before transmitting taste-related signals to the PbN. NTS cells of varied response profiles send converging input to PbN cells, though input from NTS cells with similar profiles is more effective at driving PbN responses. PbN cells follow NTS input for the first 3 s of taste stimulation for NaCl, HCl, and quinine, but are driven in cyclic bursts throughout the response interval for sucrose. Analyses of the temporal characteristics of NTS and PbN responses show that both structures use temporal coding with equal effectiveness to identify taste quality. Thus, the NTS input to the PbN is comprehensive, in that PbN cells receive NTS input that could support broad sensitivity, systematic, in that the time course of PbN firing patterns depend reliably on the tastant, and efficient, in that information from the NTS is preserved as it is communicated across structures. Comparisons of NTS and PbN taste responses in rats form the basis for our speculation that in primates, where the central gustatory pathway does not synapse in the PbN, the function of the PbN in taste processing may have been incorporated into that of the NTS.
作为啮齿动物中枢味觉通路的第二个突触，脑桥臂旁核（PbN）直接从孤束核（NTS）接收味觉刺激信息。数据显示，NTS细胞在将味觉相关信号传递至PbN之前会放大味觉反应。具有不同反应模式的NTS细胞向PbN细胞发送汇聚输入，尽管来自具有相似模式的NTS细胞的输入在驱动PbN反应方面更有效。对于氯化钠、盐酸和奎宁，PbN细胞在味觉刺激的前3秒跟随NTS输入，但对于蔗糖，在整个反应间隔内以周期性爆发的形式被驱动。对NTS和PbN反应的时间特征分析表明，这两个结构都以相同的有效性使用时间编码来识别味觉质量。因此，NTS向PbN的输入是全面的，因为PbN细胞接收的NTS输入可以支持广泛的敏感性；是系统的，因为PbN放电模式的时间进程可靠地取决于味觉物质；是高效的，因为来自NTS的信息在跨结构传递时得以保留。大鼠中NTS和PbN味觉反应的比较为我们的推测提供了基础，即在灵长类动物中，中枢味觉通路不在PbN中形成突触，PbN在味觉处理中的功能可能已被纳入NTS的功能之中。
