EVIDENCE FOR A VISCEROTOPIC SENSORY REPRESENTATION IN THE CORTEX AND THALAMUS IN THE RAT
EVIDENCE FOR A VISCEROTOPIC SENSORY REPRESENTATION IN THE CORTEX AND THALAMUS IN THE RAT
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DOI：
10.1002/cne.902620104
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发表时间：
1987-08-01
影响因子：
2.5
通讯作者：
SAPER, CB
中科院分区：
文献类型：
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作者：
CECHETTO, DF;SAPER, CB
岛叶皮层的功能组织进行了研究，通过记录内脏感觉刺激的神经元反应。辣根过氧化物酶（HRP），然后离子电渗在记录网站，以确定传入从腹侧丘脑特定的内脏在岛叶皮质的网站。腹侧丘脑的岛叶皮质和脑干中继核团的上升内脏投射的关系，然后通过使用轴突运输的HRP，麦胚凝集素结合HRP（WGA-HRP），和荧光染料进行检查。在总共55个神经元中，测试了对内脏感觉刺激的反应，33个单位对至少一种内脏感觉方式作出反应：6个单位接受胃机械感受器输入，8个单位对味觉输入作出反应，13个单位被动脉化学感受器激活和/或显示呼吸相关活动，6个单位对心血管压力感受器刺激作出反应。根据其细胞结构和与丘脑的联系，岛叶皮质分为背侧颗粒区、中间颗粒异常区和腹侧无颗粒带。味觉反应神经元位于前方，主要是在dysgranular区域，而一般内脏方式的单位反应分布在背侧和后方的颗粒岛皮质。胃机械感受器反应单位位于更多的背侧和前部的颗粒岛皮质，而心肺输入位于更多的腹侧和后部。将HRP注射到味觉岛叶皮质，导致丘脑腹后内侧核（VPMpc）小细胞部分神经元的逆行标记。注射到一般内脏岛皮质逆行标记的神经元VPMpc侧的腹后外侧小细胞丘脑核（VPLpc）。注射HRP，WGA-HRP，和荧光染料到VPMpc和VPLpc验证，他们的投影岛叶皮质的地形组织。在同样的实验中，臂旁核中的逆行标记神经元识别了该核中可能的亚核，这些亚核将内脏感觉信息传递到丘脑。将WGA-HRP注入臂旁核表明，其向丘脑腹侧基底核的投射也是地形组织的。这些结果表明，一般的内脏和特殊的内脏（味道）在岛叶皮层代表的关系。内脏感觉信息的上行通路似乎在包括岛叶皮质在内的所有水平的神经轴上都是内脏组织的。
The functional organization of the insular cortex was studied by recording neuronal responses to visceral sensory stimuli. Horseradish peroxidase (HRP) was then iontophoresed at the recording sites to identify afferents from the ventrobasal thalamus to specific visceroceptive sites in the insular cortex. The relationship of the ventrobasal thalamus to the insular cortex and to brainstem relay nuclei for the ascending visceral projections was then examined by using the axonal transport of HRP, wheat germ agglutinin conjugated to HRP (WGA-HRP), and fluorescent dyes. Of a total of 55 neurons that were tested for responses to visceral sensory stimuli, 33 units responded to at least one visceral sensory modality: 6 received gastric mechanoreceptor input, 8 responded to taste inputs, 13 were activated by arterial chemoreceptors and/or showed respiratory related activity, and 6 responded to cardiovascular baroreceptor stimulation. On the basis of its cytoarchitecture and connections with the thalamus, the insular cortex was divided into a dorsal granular area, an intermediate dysgranular region, and a ventral agranular strip. Taste-responsive neurons were located anteriorly, primarily in the dysgranular region, whereas unit responses to general visceral modalities were distributed dorsally and posteriorly in the granular insular cortex. Gastric mechanoreceptor-responsive units were situated more dorsally and anteriorly in the granular insular cortex, while cardiopulmonary inputs were located more ventrally and posteriorly. Injections of HRP into the gustatory insular cortex resulted in retrograde labeling of neurons in the parvicellular part of the ventroposterior medial thalamic nucleus (VPMpc). Injections into the general visceral insular cortex retrogradely labeled neurons lateral to VPMpc in the ventroposterior lateral parvicellular thalamic nucleus (VPLpc). Injections of HRP, WGA-HRP, and fluorescent dyes into VPMpc and VPLpc verified that their projection to the insular cortex is topographically organized. In the same experiments, retrogradely labeled neurons in the parabrachial nucleus identified the likely subnuclei within this nucleus for relay of visceral sensory information to the thalamus. Injections of WGA-HRP into the parabrachial nucleus demonstrated that its projection to the ventrobasal thalamus is also topographically organized. These results demonstrate the relationship of general visceral and special visceral (taste) representations in the insular cortex. The ascending pathway for visceral sensory information appears to be viscerotopically organized at all levels of the neuraxis, including the insular cortex.