SPINOHYPOTHALAMIC AND SPINOTELENCEPHALIC TRACTS

几年前，我们在电生理研究中注意到， 大鼠腰髓内神经元的数量可能是 从下丘脑逆行激活使用少量的 电流。这些发现表明，存在一种投影，即 从脊髓携带躯体感觉和伤害性信息 直接连接到下丘脑。我们用了几个解剖学和 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，在老鼠身上 下丘脑脊束和丘脑脊束总数 神经元是相似的。在脊髓的胸段和骶段，有 下丘脑棘束神经元的数量要比 脊髓丘脑束神经元。下丘脑脊束是有意义的。 因为它可能是对地区的重要投入来源 下丘脑被认为在自主神经中发挥重要作用， 神经内分泌和对躯体感觉刺激的情感反应。在……里面 在第一系列研究中，我们将考察反应特征 对猴子的SHT神经元的研究。在第二个阶段中，我们将确定 脊髓丘脑束轴突在脊髓白质内的定位 猴子。在第三组研究中，我们将确定功能 下丘脑脊束神经元数量众多的特点 在大鼠的胸髓内。在这些研究中，我们将使用 皮肤和内脏结构的定量刺激。我们会 也要测试SHT神经元能够提供 起源于乳头至下丘脑神经元的感觉信息 与排乳反射有关。在第四系列研究中，我们 将生理特征的SHT神经元在节段c1-2 老鼠。我们还将在细胞内记录这些神经元并注入 给他们注射神经生物素。这些实验应该揭示出完整的 SHT细胞体和树突的形态。此外，他们还 应提供有关这类神经元轴突的详细信息 它们在脑干内的侧支投射。我们还将录制 从后间脑轴突内的SHT单位注入 给他们注射神经生物素。这些研究应该会揭示出 SHT轴突及其侧支的生理特征 在间脑的两侧。

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.