SPINOHYPOTHALAMIC AND SPINOTELENCEPHALIC TRACTS

几年前，我们在电生理学研究中注意到， 大鼠腰段脊髓神经元数量可 从下丘脑逆向激活，使用少量 电流 这些发现表明存在一种预测， 从脊髓传递躯体感觉和伤害感受信息 直接连接到下丘脑 我们使用了几种解剖学和 生理技术来证实这种投射的存在。 有趣的是，我们的逆行追踪研究表明，在大鼠中， 脊髓下丘脑束和脊髓丘脑束总数 神经元是相似的。 在脊髓的胸椎和骶骨水平， 脊髓下丘脑束神经元比 脊髓丘脑束神经元 我们感兴趣的是脊髓下丘脑束 因为它可能是一个重要的输入来源， 下丘脑被认为在自主神经， 对躯体感觉刺激的神经内分泌和情感反应。在 在第一系列研究中，我们将研究 的SHT神经元。 第二，我们将确定 脊髓丘脑束轴突在脊髓白色物质中的位置 猴子 在第三组研究中，我们将确定功能 大量脊髓下丘脑束神经元的特征 在大鼠的胸脊髓中。 在这些研究中，我们将使用 皮肤和内脏结构的定量刺激。 我们将 还测试了SHT神经元能够提供 从乳头到下丘脑神经元的感觉信息 参与了排乳反射 在第四个系列研究中，我们 将在生理学上表征SHT神经元在C1-2节段中， 大鼠 我们还将记录这些神经元的细胞内， 用神经生物素。 这些实验应该能揭示 SHT细胞体和树突的形态。 此外他们 应该提供这些神经元轴突的详细信息， 它们在脑干内的侧支投射 我们还将记录 从间脑后部的轴内SHT单位， 用神经生物素。 这些研究应该揭示 生理学特征的SHT轴突及其侧支 在间脑两侧

Several years ago, we noted during electrophysiological studies that a number of neurons in the lumbar spinal cords of rats could be antidromically activated from the hypothalamus using small amounts of current. These findings suggested the existence of a projection that carries somatosensory and nociceptive information from the spinal cord directly to the hypothalamus. We used several anatomical and physiological techniques to confirm the existence of this projection. Interestingly, our retrograde tracing studies indicated that in rats the total numbers of spinohypothalamic tract and spinothalamic tract neurons are similar. In thoracic and sacral levels of the cord, there are considerably more spinohypothalamic tract neurons than spinothalamic tract neurons. The spinohypothalmic tract is of interest because it may be an important source of input to areas of the hypothalamus that are thought to play important roles in autonomic, neuroendocrine and affective responses to somatosensory stimuli. In the first series of studies, we will examine the response characteristics of SHT neurons in monkeys. In the second, we will determine the location of spinothalamic tract axons in the spinal cord white matter in monkeys. In the third set of studies, we will determine the functional characteristics of the large number of spinohypothalamic tract neurons in the thoracic spinal cord of rats. In these studies, we will use quantitative stimulation of cutaneous and visceral structures. We will also test the hypothesis that SHT neurons are capable of providing sensory information originating in the nipples to hypothalamic neurons involved in the milk-ejection reflex. In the fourth series of studies, we will physiologically characterize SHT neurons in segments C1-2 of rats. We will also record from such neurons intracellularly and inject them with neurobiotin. These experiments should reveal the complete morphology of SHT cell bodies and dendrites. In addition, they should provide detailed information on the axons of such neurons and their collateral projections within the brainstem. We will also record from SHT units intraaxonally in the posterior diencephalon and inject them with neurobiotin. These studies should reveal the morphology of physiologically characterized SHT axons and their collaterals bilaterally in the diencephalon.