ORGANIZATION OF THE LAMINA I STT PROJECTION

目前的研究解决了这样的假设：椎板I 脊髓丘脑束(Lami-STT)神经元是必不可少的底物 痛觉和热感受器的中枢表征 作为特定的感觉模式，即它们构成了中枢 包含专一性理论的“标记线”的路径 痛感和体温感。这些实验的重点是 这条途径的功能选择性组织和 尤其集中于检查可能反映出 伤害性和致痛性的不同功能和解剖学分类 生理学鉴定的热感受性Laml-STT神经元 之前在猫身上的工作。新凝集素(PHA-L)顺行 将使用追踪法精确确定多个 Laml-STT a丘脑终末部位，以表征其 并确定它们的途径。化学物质和 这些末端突起的解剖选择性将被测试 用免疫组织化学方法检测内源性神经化学物质， 以及多种逆行示踪剂的双重标记方法 分离的传入细胞群的鉴定。此外, 生理学实验将补充解剖学 Lami-STI脊髓上行通路的定位 对已识别细胞的轴突进行个别定位 L2处微电极的逆行激活。这些 实验将直接决定Lami-STT轴突是否投射 与经典的STI分开，正如一些人所建议的那样，以及 伤害性轴突和感热性轴突是否一起运动。这个 紧张性递减效应对机体功能的影响 这些LAMI-STT细胞以及其他非STT椎板的选择性 I细胞将用可逆性脊髓冷块进行检查。 最后，这些细胞对局部应用的敏感性 将对(鞘内)吗啡进行评估，以测试其 功能分化，通过将这种敏感性与 鞘内镇痛的报道特征，TO 验证了他们在 伤害性感受。

The present research addresses the hypothesis that lamina I spinothalamic tract (lamI-STT) neurons are an essential substrate for the central representation of nociception and thermoreception as specific sensory modalities, i.e. that they constitute a central pathway that contains the "labeled lines" of specificity theory for pain and temperature sensation. These experiments focus on the functionally selective organization of this pathway and particularly concentrate on examining attributes which may reflect the distinct functional and anatomical classes of nociceptive and thermoreceptive laml-STT neurons identified physiologically in previous work in the cat. The new lectin (PHA-L) anterograde tracing method will be used to precisely determine the multiple laml-STT a thalamic termination sites, to characterize their morphology and to identify their pathway. The chemical and anatomical selectivity of these terminal projections will be tested with immunohistochemical the detection of endogenous neurochemical, and double-labeling methods for multiple retrograde tracers for the identification of segregated afferent cell groups. In addition, physiological experiments will complement the anatomical localization of the ascending lamI-STI spinal pathway with the individual localization of the axons of identified cells by antidromic activation from a microelectrode at L2. These experiments will directly determine whether lamI-STT axons project separately from the classical STI, as some have proposed, and whether nociceptive and thermoreceptive axons course together. The effects of tonic descending influences on the functional selectivity of these lamI-STT cells and also other non-STT lamina I cells will be examined with reversible spinal cold blocks. Lastly, the sensitivity of these cells to topically applied (intrathecal) morphine will be assessed in order to test their functional differentiation and, by comparing this sensitivity to reported characteristics of intrathecally produced analgesia, to verify the hypothesis that they play an essential role in nociception.