Phillips J O, Fuchs A F, Ling L, Iwamoto Y, Votaw S
Department of Physiology and Biophysics and Regional Primate Research Center, University of Washington, Seattle, Washington 98195, USA.
J Neurophysiol. 1997 Nov;78(5):2817-21. doi: 10.1152/jn.1997.78.5.2817.
Gain adaptation of eye and head movement components of simian gaze shifts. J. Neurophysiol. 78: 2817-2821, 1997. To investigate the site of gaze adaptation in primates, we reduced the gain of large head-restrained gaze shifts made to 50 degrees target steps by jumping the target 40% backwards during a targeting saccade and then tested gain transfer to the eye- and head-movement components of head-unrestrained gaze shifts. After several hundred backstep trials, saccadic gain decreased by at least 10% in 8 of 13 experiments, which were then selected for further study. The minimum saccadic gain decrease in these eight experiments was 12.8% (mean = 18.4%). Head-unrestrained gaze shifts to ordinary 50 degrees target steps experienced a gain reduction of at least 9.3% (mean = 14.9%), a mean gain transfer of 81%. Both the eye and head components of the gaze shift also decreased. However, average head movement gain decreased much more (22.1%) than eye movement gain (9.2%). Also, peak head velocity generally decreased significantly (20%), but peak eye velocity either increased or remained constant (average increase of 5.6%). However, the adapted peak eye and head velocities were appropriate for the adapted, smaller gaze amplitudes. Similar dissociations in eye and head metrics occurred when head-unrestrained gaze shifts were adapted directly (n = 2). These results indicated that head-restrained saccadic gain adaptation did not produce adaptation of eye movement alone. Nor did it produce a proportional gain change in both eye and head movement. Rather, normal eye and head amplitude and velocity relations for a given gaze amplitude were preserved. Such a result could be explained most easily if head-restrained adaptation were realized before the eye and head commands had been individualized. Therefore, gaze adaptation is most likely to occur upstream of the creation of separate eye and head movement commands.
猴类注视转移中眼动和头动成分的增益适应。《神经生理学杂志》78: 2817 - 2821, 1997年。为了研究灵长类动物中注视适应的位点，我们通过在目标扫视过程中将目标向后跳跃40%，将大的头部固定注视转移至50度目标步幅的增益降低，然后测试向头部无约束注视转移的眼动和头动成分的增益转移。经过数百次后跳试验，13个实验中有8个实验的扫视增益至少降低了10%，随后选择这些实验进行进一步研究。这8个实验中扫视增益的最小降低为12.8%（平均值 = 18.4%）。向普通50度目标步幅的头部无约束注视转移经历了至少9.3%的增益降低（平均值 = 14.9%），平均增益转移为81%。注视转移的眼动和头动成分均降低。然而，平均头动增益降低（22.1%）比眼动增益降低（9.2%）多得多。此外，峰值头速度通常显著降低（20%），但峰值眼速度要么增加要么保持不变（平均增加5.6%）。然而，适应后的峰值眼速度和头速度与适应后的较小注视幅度相匹配。当直接对头部无约束注视转移进行适应时（n = 2），在眼动和头动指标上也出现了类似的分离。这些结果表明，头部固定扫视增益适应并非仅产生眼动适应。它也没有在眼动和头动中产生成比例的增益变化。相反，对于给定的注视幅度，正常的眼动和头动幅度及速度关系得以保留。如果头部固定适应在眼动和头动指令个体化之前实现，这样的结果最容易得到解释。因此，注视适应最有可能发生在单独的眼动和头动指令产生之前的上游。
