ORGANIZATION OF THE LAMINA I STT PROJECTION

本研究项目是基于这样的概念，即背侧第一层 角是疼痛的中枢表现的组成部分， 温度敏感性仅椎板I接受小直径原发灶 来自身体所有组织的传入输入，并包含特定的 伤害感受神经元和温度感受神经元的浓度。板层I神经元 形成脊髓丘脑束（STT）的一半，它们的上行轴突是 集中在疼痛和温度感觉的关键部位。 椎板I投射的功能和解剖组织需要 有待阐明。 在上一个赠款期间，我们确定了 解剖学、免疫组织化学和生理学方法， 用于疼痛和温度的板层I STT丘脑中继核（VMpo） 感觉在猕猴和人类，我们展示了板层I 本体脊髓和脑干投射，可以提供基础， 伤害性和热性躯体自主神经反射。 在猫身上，我们也 确定了三个主要的生理/形态类的叶片I STT 细胞，表明它们具有选择性丘脑投射， 表明，一个简单的模型，丘脑皮层整合的 这些板层I STT感觉通道的活动可以解释热传导， 烧烤幻觉和冷痛的灼烧。 所提出的实验解决椎板I的功能解剖 脊髓-丘脑-皮质通路。我们将（i）确定是否 主要椎板I STT投射的皮质投射靶向， 我们在猴中鉴定出的（VMpo、VPI和MDvc）与 在人类PET研究中，疼痛激活的主要皮质区，（2）确定 是否不同形态的I层STT神经元 在猫中识别的，在猴子和项目中是可区分的 差异，（3）检查是否VMpo和邻近结构， 猴子和人类的丘脑是化学结构组织的，（4） 定量地确定是否生理上不同类别的 层I STT细胞存在于猴中，如同在猫中鉴定的那些， 和（5）定量测定VMpo神经元是否维持 I层反应类别的生理特异性或显示出 I层STT输入的整合会聚。热格栅和 还将使用瘙痒诱导剂组胺来检查 假定的层I STT活性的整合发生在VMpo中。 这些实验测试特定的假设，描绘积分 特定疼痛和温度的中枢基质成分 在猴子和人类中的敏感性。 我们认为假设模型 第一层感觉通道的丘脑-皮质整合可以提供 冷异常性疼痛和烧灼感痛的基础， 典型的（中枢性卒中后）丘脑疼痛综合征的特征。

This research project is based on the concept that lamina I of the dorsal horn is an integral component of the central representation of pain and temperature sensibility. Only lamina I receives small-diameter primary afferent input from all tissues of the body and contains a specific concentration of nociceptive and thermoreceptive neurons. Lamina I neurons form half of the spinothalamic tract (STT), and their ascending axons are concentrated in the critical location for pain and temperature sensation. The functional and anatomical organization of lamina I projections needs to be elucidated. In the preceding grant period, we identified with anatomical, immunohistochemical and physiological methods a specific lamina I STT thalamic relay nucleus (VMpo) for pain and temperature sensation in macaques and humans, and we demonstrated lamina I propriospinal and brainstem projections that could provide the basis for noxious and thermal somato-autonomic reflexes. In cats, we also identified three major physiological/morphological classes of lamina I STT cells, showed that they have selective thalamic projections, and demonstrated that a simple model of thalamo-cortical integration of the activity of these lamina I STT sensory channels can explain the thermal grill illusion and the burn of cold pain. The proposed experiments address the functional anatomy of the lamina I spino-thalamo-cortical pathway in primates. We will (i) determine whether the cortical projections of the major lamina I STT projection targets that we have identified (VMpo, VPI, and MDvc) in the monkey correspond with the major cortical areas activated by pain in human PET studies, (2) determine whether the different morphological classes of lamina I STT neurons identified in the cat are distinguishable in the monkey and project differentially, (3) examine whether VMpo and neighboring structures in monkey and human thalamus are chemoarchitectonically organized, (4) quantitatively determine whether physiologically distinct classes of lamina I STT cells exist in the monkey like those identified in the cat, and (5) quantitatively determine whether VMpo neurons maintain the physiological specificity of lamina I response classes or show evidence of integrative convergence of lamina I STT inputs. The thermal grill and the itch-inducing agent histamine will also be used to examine whether the postulated integration of lamina I STT activity occurs in VMpo. These experiments test specific hypotheses that delineate integral components of the central substrates of specific pain and temperature sensibility in monkeys and humans. We believe that the postulated model of thalamo-cortical integration of lamina I sensory channels could provide a basis for the cold allodynia and burning dysesthetic pain that characterize the classic (central post-stroke) thalamic pain syndrome.