Yamasaki D S, Krauthamer G M
Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854.
Brain Res. 1990 Jul 23;523(2):188-94. doi: 10.1016/0006-8993(90)91486-z.
Neurons of the rat superior colliculus projecting to the intralaminar thalamus were tested for their responses to somatosensory stimulation. They were identified by antidromic stimulation of the parafascicular nucleus and central lateral nucleus. To establish the existence of descending as well as ascending axon collaterals antidromic stimulation was applied to the upper cervical spinal cord in some cases. Somatosensory receptive fields were delineated and their laminar location in the superior colliculus was noted. Units were distributed throughout the intermediate and deep tectal layers, none were located in the superficial layers. Units with somatosensory receptive fields could be classified as low threshold, high threshold, wide dynamic range or complex. The majority of the peripherally responsive units (52%) were low threshold somatosensory units with contralateral receptive fields. All units were distributed throughout the intermediate and deep layers. Their distribution reflected the typical somatotopic organization of the superior colliculus. These results indicate that the intralaminar thalamus receives some sensory information by way of the tectum. In turn, the basal ganglia may gain direct access to this information by way of the thalamoneostriatal projection.
对投射至丘脑板内核的大鼠上丘神经元进行了体感刺激反应测试。通过对束旁核和中央外侧核的逆向刺激来识别这些神经元。为了确定下行以及上行轴突侧支的存在，在某些情况下对上颈段脊髓进行逆向刺激。描绘了体感感受野，并记录了它们在上丘中的分层位置。神经元分布于整个中脑顶盖的中间层和深层，无神经元位于表层。具有体感感受野的神经元可分为低阈值、高阈值、宽动态范围或复杂型。大多数外周反应性神经元（52%）是具有对侧感受野的低阈值体感神经元。所有神经元均分布于中间层和深层。它们的分布反映了上丘典型的躯体定位组织。这些结果表明，丘脑板内核通过顶盖接收一些感觉信息。反过来，基底神经节可能通过丘脑新纹状体投射直接获取该信息。
