Institute of Psychology and Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, Univ. of Muenster, Münster, Germany.
J Neurophysiol. 2012 Jun;107(11):3062-70. doi: 10.1152/jn.00877.2011. Epub 2012 Mar 21.
Recent studies have shown that saccadic inward adaptation (i.e., the shortening of saccade amplitude) and saccadic outward adaptation (i.e., the lengthening of saccade amplitude) rely on partially different neuronal mechanisms. There is increasing evidence that these differences are based on differences at the target registration or planning stages since outward but not inward adaptation transfers to hand-pointing and perceptual localization of flashed targets. Furthermore, the transfer of reactive saccade adaptation to long-duration overlap and scanning saccades is stronger after saccadic outward adaptation than that after saccadic inward adaptation, suggesting that modulated target registration stages during outward adaptation are increasingly used in the execution of saccades when the saccade target is visually available for a longer time. The difference in target presentation duration between reactive and scanning saccades is also linked to a difference in perceptual localization of different targets. Flashed targets are mislocalized after inward adaptation of reactive and scanning saccades but targets that are presented for a longer time (stationary targets) are mislocalized stronger after scanning than after reactive saccades. This link between perceptual localization and adaptation specificity suggests that mislocalization of stationary bars should be higher after outward than that after inward adaptation of reactive saccades. In the present study we test this prediction. We show that the relative amount of mislocalization of stationary versus flashed bars is higher after outward than that after inward adaptation of reactive saccades. Furthermore, during fixation stationary and flashed bars were mislocalized after outward but not after inward adaptation. Thus, our results give further evidence for different adaptation mechanisms between inward and outward adaptation and harmonize some recent research.
最近的研究表明，扫视内适应（即扫视幅度缩短）和扫视外适应（即扫视幅度延长）依赖于部分不同的神经元机制。越来越多的证据表明，这些差异基于目标登记或规划阶段的差异，因为外适应而不是内适应可以转移到手指向和闪烁目标的感知定位。此外，反应性扫视适应向长时间重叠和扫描扫视的转移在外适应后比内适应后更强，这表明在外适应期间，目标登记阶段的调制在扫视目标可长时间可见时，在扫视执行中被越来越多地使用。反应性和扫描扫视之间的目标呈现持续时间的差异也与不同目标的感知定位差异有关。在反应性和扫描扫视的内适应后，闪烁目标会被错误定位，但在扫描后比在反应性扫视后，长时间呈现的目标（固定目标）会被错误定位得更严重。这种感知定位和适应特异性之间的联系表明，在反应性扫视的外适应后，固定棒的错误定位应该高于内适应。在本研究中，我们检验了这一预测。我们表明，在反应性扫视的外适应后，固定棒相对于闪烁棒的错误定位量高于内适应后。此外，在注视期间，固定棒和闪烁棒在外适应后而不是内适应后被错误定位。因此，我们的结果为内适应和外适应之间的不同适应机制提供了进一步的证据，并协调了一些最近的研究。
