cerebellar output pathway involved in saccadic gain adaptation

1)猴子的正视动眼肌区（fort）失活的影响已知单侧fort失活会导致显著的扫视性高跳。这是由于在不同幅度的跳频上均匀的增益变化，即参数增益变化，还是由于与运动幅度无关的恒定大小的超调，如先前在cat中的研究所表明的那样，这仍然是一个悬而未决的问题。我们分析了猴子单侧FOR失活后的测量障碍，并得出结论，由此产生的超调是由于所有大小的眼跳均匀增加。2)跳跃性适应过程中FOR活性的变化。上述研究和其他有关FOR失活的研究结果表明，FOR对扫视性跳跃性具有抑制作用。如果前脑区参与了眼跳幅度的自适应调节，那么其与眼跳相关的活动将随着眼跳大小的减小而增加。我们从猴子的单个FOR神经元中记录了随着扫视增益的减少。随着增重的减少，促生成素活性增加。在适应过程中，神经元活动和增益的变化过程相似，但方向相反。因此，该结果与假设的FOR活性对扫视性扫视的抑制作用一致，并在单个神经元的基础上为小脑参与扫视适应性提供了支持。

1) Effects of inactivating the fastigial oculomotor region (FOR) in the monkey Unilateral inactivation of the FOR is known to result in marked hypermetria of ipsiversive saccades. It remains an open question whether this is due to a uniform gain change over saccades of different amplitudes, i.e., a parametric gain change, or due, instead, to an overshoot of a constant size regardless of movement amplitudes, as suggested by a previous study in the cat. We analyzed dysmetria following unilateral FOR inactivation in the monkey and concluded that the resultant overshoots were due to a uniform gain increase for saccades of all sizes.2) Changes in FOR activity during saccadic adaptation The results of the above and other FOR inactivation studies suggest that the FOR exerts a suppressive action on ipsiversive saccades. If the FOR is involved in adaptive modification of saccade amplitude, its saccade-related activity is expected to increase as the saccade size in decreased. We recorded from single FOR neurons in the monkey as the gain of ipsiversive saccades was decreased. The FOR activity was found to increase as the gain was decreased. During the course of adaptation, the neuronal activity and gain were altered with a similar course but in the opposite directions. The results are thus consistent with the hypothesized suppressive action of FOR activity on ipsiversive saccades and provide support on a single neuron basis for the cerebellar involvement in saccadic adaptation.