Testing models of the oculomotor velocity-to-position transformation.
Testing models of the oculomotor velocity-to-position transformation.
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DOI：
10.1152/jn.1994.72.3.1425
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发表时间：
1994-09
影响因子：
2.5
通讯作者：
D. Tweed;H. Misslisch;Michael Fetter
中科院分区：
文献类型：
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作者：
D. Tweed;H. Misslisch;Michael Fetter
1. 运动前回路中的神经计算是否反映了它们控制的系统的物理特性？ 1987年，Tweed和Vilis表明，神经积分器将眼睛角速度命令转换为位置命令的动眼理论是不正确的，因为角位置不是角速度的积分。最近，Schnabolk 和 Raphan 提出，角速度积分器仍可用于在动眼神经系统中生成强直命令。在这里，我们对照 Tweed 和 Vilis 的速度到位置变换的四元数 (Q) 模型测试 Schnabolk-Raphan (S-R) 模型。 2. S-R 模型预测在尝试水平和垂直扫视期间扭转眼睛位置会出现较大（最多 7 度）瞬态（大约 700 毫秒）偏差（“光点”）。 Q 模型预测不会出现任何现象。 7 名正常人类受试者的扫视搜索线圈记录没有显示大的光点。 3. 对于每个受试者大约 200 次眼跳，我们绘制了扭转尖点下方的面积与眼跳偏心率和幅度的乘积。根据 S-R 模型，该图应形成一条斜率为 1.00 的直线。根据 Q 模型，斜率应为零。对于偏心率为 20 度的扫视目标，测量的斜率平均为 0.016（范围为 -0.073 至 0.061）；对于偏心率为 40 度的目标，测量的斜率平均为 0.040（范围为 0.004-0.076）。 4. 不改变参数可以显着改善S-R模型，但降低一个参数可以消除Q模型中的微小误差。我们证明了 S-R 模型失败的根本原因是它使用交换控制器来引导非交换对象。
1. Do neural computations in premotor circuits mirror the physical properties of the systems they control? In 1987, Tweed and Vilis showed that oculomotor theories where a neural integrator converts eye angular velocity commands into position commands cannot be correct, because angular position is not the integral of angular velocity. Recently Schnabolk and Raphan proposed that an angular velocity integrator is nevertheless used to generate tonic commands in the oculomotor system. Here we test the Schnabolk-Raphan (S-R) model against Tweed and Vilis's quaternion (Q) model of the velocity to position transformation. 2. The S-R model predicts large (up to 7 degrees) transient (approximately 700 ms) deviations ("blips") in torsional eye position during attempted horizontal and vertical saccades. The Q model predicts no blips. Search coil recordings of saccades by 7 normal human subjects showed no large blips. 3. For approximately 200 saccades by each subject, we plotted the area under the torsional blip versus the product of saccade eccentricity and magnitude. According to the S-R model, this graph should form a straight line with slope 1.00. According to the Q model, the slope should be zero. Measured slopes averaged 0.016 (range -0.073 to 0.061) for saccade targets at 20 degrees eccentricity and 0.040 (range 0.004-0.076) for targets at 40 degrees. 4. No parameter change can significantly improve the S-R model, but lowering one parameter eradicates the tiny inaccuracy in the Q model. We show that the fundamental reason for the S-R model's failure is its use of a commutative controller to steer a noncommutative plant.