Fine Structure of Lamina I TSST Terminals in VP

VP 中 Lamina I TSST 端子的精细结构

• 批准号: 6680136
• 负责人: ARTHUR D CRAIG
• 金额: $ 14.99万
• 依托单位: ST. JOSEPH'S HOSPITAL AND MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-12-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6680136
• 关键词: Macaca fascicularis; brain mapping; brain morphology; central neural pathway /tract; computational neuroscience; histology; intercellular connection; neural information processing; pain; physical model; sensory mechanism; subthalamus; synapses; thalamic nuclei

DESCRIPTION (provided by applicant): In order to understand the organization of central pathways for pain in humans, we need to know the underlying anatomical substrates in the primate brain. During the past several years, we have characterized a thalamic nucleus in monkeys and humans (VMpo) that, we believe, serves as a specific thalamocortical relay nucleus for pain, temperature, itch and other sensations related to the physiological condition of the body. This hypothesis differs from the conventional view that the ventral posterior nuclei (VP) are crucial for pain sensation, but it is supported by growing evidence. The preceding cycle of this NIH grant enabled us to test this hypothesis by examining the synaptology of lamina I trigemino- and spino-thalamic (TSTT) terminations in VMpo. Using three-dimensional models built from serial ultra-thin sections through anterogradely-labeled lamina I TSTT terminal fibers, we showed that lamina I terminations in VMpo have distinct characteristics (multiple contacts on single post-synaptic dendrites in triadic arrangements with presynaptic dendrites) that provide the basis for secure, high-fidelity synaptic transmission, consistent with a relay function. This contrasts strongly with prior ultrastructural observations by reliable investigators indicating that TSTT terminals in the primate thalamus generate single, isolated boutons that do not provide the basis for secure, high-fidelity synaptic contacts. That prior study focused on VP, but it also examined the region of VMpo; yet, it did not differentiate lamina I from lamina V TSTT terminations, which may have entirely different functional roles. We propose to resolve this discrepancy by directly examining the synaptology of identified lamina I TSTT terminations in VP. If lamina I TSTT terminations in VP form secure, high-fidelity synaptic contacts like they do in VMpo, this would support the view that both these regions have an important role in pain. Alternatively, if lamina I TSTT terminations in VP form single contacts, as suggested by prior observations, this would indicate that the synaptic transfer of pain-related activity in VMpo and VP is qualitatively different, supporting our view that VMpo and VP have different roles in sensation, and underscoring the significance of VMpo as a lamina I sensory relay nucleus. These studies will advance our understanding of the anatomical substrates for pain sensation in the primate thalamus.

描述（由申请人提供）：为了了解人类疼痛的中枢通路的组织，我们需要了解灵长类动物大脑的基本解剖结构。在过去的几年里，我们对猴子和人类的丘脑核（VMpo）进行了表征，我们相信它是一个特定的丘脑皮质中继核，负责疼痛、温度、瘙痒和其他与身体生理状况相关的感觉。这一假说与腹侧后核（VP）对痛觉至关重要的传统观点不同，但它得到了越来越多证据的支持。 NIH 资助的前一个周期使我们能够通过检查 VMpo 中的 lamina I 三叉神经和脊髓丘脑 (TSTT) 终止的突触学来检验这一假设。使用通过顺行标记的层板 I TSTT 末端纤维从连续超薄切片构建的三维模型，我们表明 VMpo 中的层板 I 终止具有独特的特征（与突触前树突呈三元排列的单个突触后树突上的多个接触）为安全、高保真突触传输提供基础，与中继功能一致。这与可靠研究人员之前的超微结构观察形成鲜明对比，表明灵长类丘脑中的 TSTT 终端生成单个、孤立的纽扣，这些纽扣不为安全、高保真突触接触提供基础。之前的研究主要关注 VP，但也检查了 VMpo 区域；然而，它并没有区分 I 层和 V 层 TSTT 终止，它们可能具有完全不同的功能作用。我们建议通过直接检查 VP 中已识别的层 I TSTT 终止的突触来解决这种差异。如果 VP 中的层 I TSTT 终止像 VMpo 中那样形成安全、高保真的突触接触，则这将支持这两个区域在疼痛中都发挥重要作用的观点。或者，如果 VP 中的 lamina I TSTT 终止形成单一接触，如先前观察所表明的，这将表明 VMpo 和 VP 中疼痛相关活动的突触转移在性质上是不同的，支持我们的观点，即 VMpo 和 VP 在感觉，并强调 VMpo 作为 I 层感觉中继核的重要性。这些研究将增进我们对灵长类丘脑痛觉的解剖学基础的理解。