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）：为了了解人类疼痛中枢通路的组织，我们需要了解灵长类动物大脑中的潜在解剖学基质。在过去的几年中，我们已经确定了猴子和人类的丘脑核（VMpo）的特征，我们认为，它是一个特定的丘脑皮质中继核，用于疼痛，温度，瘙痒和其他与身体生理条件相关的感觉。这一假说不同于传统的观点，即腹后核（VP）是至关重要的疼痛感觉，但它是由越来越多的证据支持。前一个周期的美国国立卫生研究院的资助，使我们能够测试这一假设，通过检查层I三叉神经和脊髓丘脑（TSTT）终止VMPO的突触学。使用三维模型建立从一系列超薄切片通过顺行标记的I层TSTT终端纤维，我们发现，I层终止VMPO有不同的特点（多个接触在单一的突触后树突与突触前树突的三联安排），提供了安全的基础，高保真突触传递，与中继功能一致。这与可靠的研究人员先前的超微结构观察结果形成强烈对比，这些观察结果表明灵长类动物丘脑中的TSTT终端产生单个孤立的终扣，这些终扣不提供安全、高保真的突触接触的基础。先前的研究集中在VP，但也检查了VMpo区域;然而，它没有区分I层和V层TSTT末端，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中确定的I层TSTT终止的突触学来解决这种差异。如果VP中的I层TSTT末端形成安全的、高保真的突触接触，就像它们在VMpo中所做的那样，这将支持这两个区域在疼痛中起重要作用的观点。或者，如果I层TSTT终止VP形成单一的联系，如先前的观察所建议的，这将表明VMPO和VP的疼痛相关活动的突触转移是定性不同的，支持我们的观点，即VMPO和VP在感觉中有不同的作用，并强调VMPO作为I层感觉中继核的重要性。这些研究将促进我们对灵长类丘脑痛觉解剖学基础的理解。