Di Lorenzo P M, Monroe S
Department of Psychology, State University of New York at Binghamton, 13902-6000, USA.
Brain Res. 1997 Jul 25;763(2):167-81. doi: 10.1016/s0006-8993(97)00217-5.
In the study of the neural code for gustation, the relative sensitivity of a cell to a variety of taste stimuli is defined as its response profile. To study the construction of response profiles from incoming signals, electrophysiological responses to NaCl, HCI, quinine-HCl, sucrose and Na saccharin were recorded simultaneously in pairs of single cells: one in the nucleus of the solitary tract (NTS) and the other in the parabrachial nucleus of the pons (PbN), respectively the first and second synapses in the central pathway for gustation. Of 37 units recorded in the NTS and 32 in the PbN, 12 (32%) pairs showed evidence of functional connectivity. Although PbN responses were significantly larger than those in the NTS in general, no amplification of NTS activity was apparent among those units that were functionally connected. Analysis of NTS-PbN connectivity patterns suggests that PbN units receive input from NTS units with response profiles that are both similar and different from their own pattern of sensitivities. Further analysis suggests that the stimulus-selectivity of the response profile of a PbN unit may be determined by stimulus-selective input from NTS cells that show similar response profiles. However, input from NTS cells with response profiles different from their own appears to be non-stimulus-selective. Analysis of the organization of response profiles in the two structures suggests that the cells in both the NTS and PbN cannot be easily distinguished by their patterns of sensitivity to taste stimuli.
在味觉神经编码的研究中，细胞对各种味觉刺激的相对敏感性被定义为其反应谱。为了研究从传入信号构建反应谱，在成对的单个细胞中同时记录了对氯化钠、盐酸、盐酸奎宁、蔗糖和糖精钠的电生理反应：一个在孤束核（NTS），另一个在脑桥臂旁核（PbN），它们分别是味觉中枢通路中的第一和第二突触。在NTS记录的37个单位和PbN记录的32个单位中，12对（32%）显示出功能连接的证据。尽管一般来说PbN的反应明显大于NTS中的反应，但在那些功能连接的单位中，NTS活动没有明显的放大。对NTS - PbN连接模式的分析表明，PbN单位从NTS单位接收输入，其反应谱与它们自己的敏感性模式既有相似之处也有不同之处。进一步的分析表明，PbN单位反应谱的刺激选择性可能由来自显示相似反应谱的NTS细胞的刺激选择性输入决定。然而，来自反应谱与它们自己不同的NTS细胞的输入似乎是非刺激选择性的。对这两种结构中反应谱组织的分析表明，NTS和PbN中的细胞不能通过它们对味觉刺激的敏感性模式轻易区分。
