Neural coding of gustatory information in the thalamus of Macaca mulatta.
Neural coding of gustatory information in the thalamus of Macaca mulatta.
复制标题
猕猴丘脑味觉信息的神经编码。
DOI：
10.1152/jn.1989.61.1.1
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发表时间：
1989
影响因子：
2.5
通讯作者：
Norgren,R
中科院分区：
文献类型：
--
作者：
Pritchard,TC;Hamilton,RB;Norgren,R
1. 在味觉、触觉和口腔热刺激下，记录了受抑制但清醒的旧大陆猴丘脑腹后内侧核细胞旁分裂的单个神经元的细胞外动作电位。与先前报道的麻醉或瘫痪大鼠相比，这些神经元的自发活动是活跃的，它们的诱发反应是强大的。2. 50个味觉反应神经元分别用1.0 M蔗糖、0.1 M NaCl、0.003 M HCl和0.001 M QHCl进行测试，然后再使用其他浓度的相同刺激。蔗糖对80%的神经元有效，在4种标准味觉刺激中引起的反应最大（16.1峰值/秒）。样本中44%的神经元对NaCl有效刺激的平均反应为7.5峰值/秒。HCl和QHCl，很少有神经元反应，通常引起较小的反应。3. 大多数神经元表现为单调的强度-响应（I-R）功能。幂函数显示大致相同程度的压缩（范围= 0.39-0.53），这与先前对麻醉啮齿动物脑干神经元的描述相同。只有9.1%的反应是抑制性的，并且这些反应没有与特定神经元或刺激相关的趋势。这些数据表明，丘脑中味觉信息的编码质量与其他物种中低阶神经元的编码质量并没有根本不同。4. 通过分层聚类分析，可以将神经元样本分为2组，其中一组由蔗糖最佳神经元组成，平均熵值为0.56。另一组神经元虽然异质性更大，但对NaCl表现出初级或侧带敏感性。用熵系数描述的50个丘脑神经元的平均反应广度为0.73。5. 除了味觉神经元外，触觉神经元（n = 15）、热神经元（n = 1）和无反应神经元（n = 25）也位于VPMpc内。另外48个神经元在本质上既不能归类为感觉神经元，也不能归类为运动神经元，它们在液体刺激开始之前抑制了它们的自发放电。这些神经元中只有2个表现出不同的化学敏感性。这些非味觉神经元在丘脑味觉区域的存在表明，VPMpc作为味觉中继的传统特征可能低估了它在摄入行为中的作用，而忽略了该区域的其他非摄入功能。
1. Extracellular action potentials were recorded from single neurons in the parvicellular division of the ventroposteromedial (VPMpc) nucleus of the thalamus of restrained, but alert, Old World monkeys during gustatory, tactile, and thermal stimulation of the oral cavity. In contrast to previous reports in anesthetized or paralyzed rats, the spontaneous activity of these neurons was brisk and their evoked responses robust. 2. Each of 50 taste-responsive neurons was tested with 1.0 M sucrose, 0.1 M NaCl, 0.003 M HCl, and 0.001 M QHCl before other concentrations of the same stimuli were used. Sucrose, which was effective in 80% of the neurons tested, evoked the largest responses of the 4 standard gustatory stimuli (16.1 spikes/s). The average response to NaCl, an effective stimulus for 44% of the neurons in the sample, was 7.5 spikes/s. HCl and QHCl, which few neurons responded to, typically evoked smaller responses. 3. Most of the neurons tested showed monotonic intensity-response (I-R) functions. The power functions showed about the same degree of compression (range = 0.39-0.53), which has been described previously for brain stem neurons in anesthetized rodents. Only 9.1% of the responses were inhibitory, and there was no tendency for these responses to be associated with either specific neurons or stimuli. These data suggest that quality coding of gustatory information in the thalamus is not radically different from that seen among lower-order neurons in other species. 4. Through the use of hierarchical cluster analysis, it was possible to divide the neuron sample into 2 groups, one of which consisted of sucrose-best neurons that had an average entropy value of 0.56. The neurons in the other group, though more heterogeneous, showed either primary or side-band sensitivity to NaCl. The average breadth of responsiveness of the 50 thalamic neurons as described by the entropy coefficient was 0.73. 5. In addition to gustatory neurons, tactile (n = 15), thermal (n = 1), and nonresponsive (n = 25) neurons also were located within VPMpc. An additional 48 neurons that could not be classified as either sensory or motor in nature, inhibited their bursting spontaneous discharge just prior to the onset of fluid stimulation. Only 2 of these neurons demonstrated differential chemical sensitivity. The presence of these nongustatory neurons within the thalamic taste area suggests that the traditional characterization of VPMpc as a gustatory relay may understate its role in ingestive behavior and ignore other noningestive functions of the area.