Commissural mirror-symmetric excitation and reciprocal inhibition between the two superior colliculi and their roles in vertical and horizontal eye movements
Commissural mirror-symmetric excitation and reciprocal inhibition between the two superior colliculi and their roles in vertical and horizontal eye movements
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DOI：
10.1152/jn.00696.2007
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发表时间：
2007-11-01
影响因子：
2.5
通讯作者：
Shinoda, Y.
中科院分区：
文献类型：
--
作者：
Takahashi, M.;Sugiuchi, Y.;Shinoda, Y.
两个上级丘（SC）之间连合兴奋和抑制的功能作用尚未得到很好的理解。我们以前表明，存在强烈的兴奋性连合连接之间的吻SC，虽然连合连接已被认为是主要是抑制。在这项研究中，通过记录细胞内电位，我们研究了连合单突触兴奋和抑制的地形分布从对侧的内侧和外侧SC顶盖网状神经元（TRN）在内侧或外侧SC麻醉猫。大约85%的TRN检查投射到同侧Forel的字段H和对侧抑制性爆发神经元区域，其中相应的运动前神经元的垂直和水平扫视驻留。内侧TRN接受来自对侧SC内侧部分的强烈连合兴奋，而外侧TRN主要接受来自其外侧部分的兴奋。将麦胚凝集素-辣根过氧化物酶注射到外侧或内侧SC中，分别逆行标记了对侧SC外侧或内侧部分的许多较大神经元。这些结果表明，兴奋性连合连接存在于吻侧SC的内侧和内侧之间以及外侧和外侧之间。这些可能分别在加强向上和向下扫视的共轭性中起重要作用。相反，内侧SC投射到外侧SC TRN和外侧SC投射到内侧TRN主要产生强抑制。这表明代表向上扫视的区域抑制代表向下扫视的对侧区域，反之亦然。
The functional roles of commissural excitation and inhibition between the two superior colliculi (SCs) are not yet well understood. We previously showed the existence of strong excitatory commissural connections between the rostral SCs, although commissural connections had been considered to be mainly inhibitory. In this study, by recording intracellular potentials, we examined the topographical distribution of commissural monosynaptic excitation and inhibition from the contralateral medial and lateral SC to tectoreticular neurons (TRNs) in the medial or lateral SC of anesthetized cats. About 85% of TRNs examined projected to both the ipsilateral Forel's field H and the contralateral inhibitory burst neuron region where the respective premotor neurons for vertical and horizontal saccades reside. Medial TRNs received strong commissural excitation from the medial part of the opposite SC, whereas lateral TRNs received excitation mainly from its lateral part. Injection of wheat germ agglutinin-horseradish peroxidase into the lateral or medial SC retrogradely labeled many larger neurons in the lateral or medial part of the contralateral SC, respectively. These results indicated that excitatory commissural connections exist between the medial and medial parts and between the lateral and lateral parts of the rostral SCs. These may play an important role in reinforcing the conjugacy of upward and downward saccades, respectively. In contrast, medial SC projections to lateral SC TRNs and lateral SC projections to medial TRNs mainly produce strong inhibition. This shows that regions representing upward saccades inhibit contralateral regions representing downward saccades and vice versa.