Interaction of the frontal eye field and superior colliculus for saccade generation
Interaction of the frontal eye field and superior colliculus for saccade generation
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DOI：
10.1152/jn.2001.85.2.804
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发表时间：
2001-02-01
影响因子：
2.5
通讯作者：
Wurtz, RH
中科院分区：
文献类型：
--
作者：
Hanes, DP;Wurtz, RH
前额叶皮层中的额叶眼场（FEF）和中脑顶部的上级丘（SC）都参与快速或扫视眼球运动的产生，并且都具有到脑干的前运动回路的投射，在脑干的前运动回路中最终产生扫视。在本实验中，我们测试的贡献的途径，从FEF的脑干，绕过SC的前运动电路。我们分析的贡献的FEF的眼跳产生唤起眼跳与直接电刺激的FEF。为了测试SC在向脑干传递信息中的作用，我们灭活了SC，从而去除了通过SC到脑干的回路，只留下直接的FEF-脑干通路。如果直接途径的贡献是实质性的，则去除SC应该对FEF刺激具有最小的影响，而如果FEF刺激依赖于SC，则去除SC应该改变FEF刺激的效果。通过急性失活的SC，而不是消融它，我们能够测试的效率的直接FEF-脑干通路之前，大量的补偿机制可以掩盖去除SC的效果。我们发现两个显着的SC失活的影响。在第一，我们刺激的FEF在一个网站，引起的扫视与载体非常接近的SC失活的网站，并与这样的最佳对齐，我们发现，SC失活消除了FEF刺激引起的扫视。第二个效果是明显的，当FEF诱发的扫视是从那些诱发的SC不同，在这种情况下，我们观察到的诱发扫视的方向，这是一致的SC失活去除一个组件的矢量平均值的转变。总之，这些观察结果得出的结论是，在非消融猴中，直接FEF-脑干通路在功能上不足以在不存在从FEF通过SC到脑干回路的间接通路的情况下产生准确的扫视。我们认为，在以前的研究中已经看到的SC消融后的功能恢复必须从使用一个已经运作的平行通路，但从扫视系统内的神经可塑性。
Both the frontal eye field (FEF) in the prefrontal cortex and the superior colliculus (SC) on the roof of the midbrain participate in the generation of rapid or saccadic eye movements and both have projections to the premotor circuits of the brain stem where saccades are ultimately generated. In the present experiments, we tested the contributions of the pathway from the FEF to the premotor circuitry in the brain stem that bypasses the SC. We assayed the contribution of the FEF to saccade generation by evoking saccades with direct electrical stimulation of the FEF. To test the role of the SC in conveying information to the brain stem, we inactivated the SC, thereby removing the circuit through the SC to the brain stem, and leaving only the direct FEF-brain stem pathway. If the contributions of the direct pathway were substantial, removal of the SC should have minimal effect on the FEF stimulation, whereas if the FEF stimulation were dependent on the SC, removal of the SC should alter the effect of FEF stimulation. By acutely inactivating the SC, instead of ablating it, we were able to test the efficiency of the direct FEF-brain stem pathway before substantial compensatory mechanisms could mask the effect of removing the SC. We found two striking effects of SC inactivation. In the first, we stimulated the FEF at a site that evoked saccades with vectors that were very close to those evoked at the site of the SC inactivation, and with such optimal alignment, we found that SC inactivation eliminated the saccades evoked by FEF stimulation. The second effect was evident when the FEF evoked saccades were disparate from those evoked in the SC, and in this case we observed a shift in the direction of the evoked saccade that was consistent with the SC inactivation removing a component of a vector average. Together these observations lead to the conclusion that in the nonablated monkey the direct FEF-brain stem pathway is not functionally sufficient to generate accurate saccades in the absence of the indirect pathway that courses from the FEF through the SC to the brain stem circuitry. We suggest that the recovery of function following SC ablation that has been seen in previous studies must result not from the use of an already functioning parallel pathway but from neural plasticity within the saccadic system.