RESPONSES OF NEURONS IN PRIMATE VENTRAL POSTERIOR LATERAL NUCLEUS TO NOXIOUS STIMULI
RESPONSES OF NEURONS IN PRIMATE VENTRAL POSTERIOR LATERAL NUCLEUS TO NOXIOUS STIMULI
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DOI：
10.1152/jn.1980.43.6.1594
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发表时间：
1980-01-01
影响因子：
2.5
通讯作者：
WILLIS, WD
中科院分区：
文献类型：
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作者：
KENSHALO, DR;GIESLER, GJ;WILLIS, WD
在麻醉猕猴[Macaca fascicularis]的丘脑腹后外侧（VPLc）核的尾侧部分进行记录。除了许多神经元只对微弱的机械刺激有反应外，还发现了分散的神经元对无害和有害刺激都有反应，或者只对皮肤的有害刺激有反应。在26只动物中总共检查了73个这样的神经元。伤害性刺激包括强烈的机械刺激（压力、捏和用镊子挤压）和分级的伤害性热刺激（从35 ° C到25 ° C）。将温度调节至43、45、47和50 ℃。C）。VPLc神经元的反应随着伤害性刺激强度的增加而进行性增加。当使用伤害性热刺激时，刺激-反应函数是指数大于1的幂函数。重复的伤害性热刺激揭示了丘脑神经元对这种刺激的反应的敏感性。对伤害性热的反应阈值降低，对阈上伤害性热刺激的反应增强。VPLc神经元对伤害性热刺激的反应在达到峰值放电频率后发生适应。对于50度的刺激，适应速度较慢。C比为47度之一。C.对于测试的6个神经元，对有害热的反应依赖于上升的途径，在腹侧的侧索对侧的感受野（同侧的丘脑神经元）。在2例中，背柱轴突传入丘脑神经元的信息也通过对侧腹象限的交叉通路传递。通过背柱上行纤维进入丘脑神经元。丘脑神经元有限制的对侧感受野，这些感受野是在躯体位置上组织的。后肢感受野的神经元位于VPLc核的外侧部分，而前肢感受野的神经元位于内侧VPLc。在对伤害性刺激有反应的VPLc神经元中，刺激SI感觉皮层表面可逆向激活90%。这些细胞中的许多通过使用微刺激投射到SI感觉皮层。成功的微刺激点要么在SI皮质内，要么在皮质下方的白色物质中。VPLc核中的一些神经元能够发出伤害性刺激的信号。伤害性信息似乎通过感受野对侧的侧索腹侧部分到达这些细胞，可能是通过脊髓丘脑束。VPLc细胞是躯体组织的，它们是投射到SI感觉皮层的丘脑皮层神经元。显然，VPLc核和SI皮层在伤害性感受中起作用。
Recordings were made from the caudal part of the ventral posterior lateral (VPLc) nucleus of the thalamus in anesthetized macaque monkeys [Macaca fascicularis]. In addition to many neurons that responded only to weak mechanical stimuli, scattered neurons were found that responded to both innocuous and noxious stimulation or just to noxious stimulation of the skin. A total of 73 such neurons were examined in 26 animals. Noxious stimuli included strong mechenical stimuli (pressure, pinch and squeezing with forceps) and graded noxious heat (from 35.degree. C adapting temperature to 43, 45, 47, and 50.degree. C). The responses of the VPLc neurons increased progressively with greater intensities of noxious stimulation. The stimulus-response function when noxious heat stimuli were used was a power function with an exponent greater than one. Repetition of the noxious heat stimuli revealed sensitization of the responses of the thalamix neurons to such stimuli. The threshold for a response to noxious heat was lowered, and the responses to suprathreshold noxious heat stimuli were enhanced. The responses of VPLc neurons to noxious heat stimuli adapted after reaching a peak discharge frequency. The rate of adaptation was slower for a stimulus of 50.degree. C than for one of 47.degree. C. For the 6 neurons tested, responses to noxious heat were dependent on pathways ascending in the ventral part of the lateral funiculus contralateral to the receptive field (ipsilateral to the thalamic neuron). In 2 cases, the input to the thalamic neurons from axons of the dorsal column was also conveyed by way of a crossed pathway in the opposite ventral quadrant. Access to the thalamic neuron by way of ascending dorsal column fibers was demonstrated. The thalamic neurons had restricted contralateral receptive fields that were somatotopically organized. Neurons with receptive fields on the hindlimb were in the lateral part of the VPLc nucleus, whereas neurons with receptive fields on the forelimb were in medial VPLc. Of the VPLc neurons tested that responded to noxious stimuli, 90% could be activated antidromically by stimulation of the surface of SI sensory cortex. Many of these cells project to the SI sensory cortex by using microstimulation. Successful microstimulation points were either within the SI cortex or in the white matter just beneath the cortex. Some neurons in the VPLc nucleus are capable of signaling nociceptive stimuli. The nociceptive information appears to reach these cells through the ventral part of the lateral funiculus on the side contralateral to the receptive field, presumably by way of the spinothalamic tract. The VPLc cells are somatopically organized, and they are thalamocortical neurons that project to the SI sensory cortex. Apparently, the VPLc nucleus and SI cortex play a role in nociception.