Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
Maastricht Centre for Systems Biology (MaCSBio), Maastricht University, Maastricht, The Netherlands.
PLoS One. 2018 Sep 10;13(9):e0201520. doi: 10.1371/journal.pone.0201520. eCollection 2018.
The last decade has seen the emergence of new views about the mechanisms underlying specificity (or, conversely, generalization) of visual skill learning. Here, we trained participants at orientation discrimination paradigm at a peripheral position to induce position and orientation specificity and to test its underlying mechanisms. Specifically, we aimed to test whether the within-quadrant spatial gradient of generalization is determined by cortical magnification, which would show that retinotopic plasticity contributes to learning and specificity. Additionally, we aimed to test whether late parts of the learning relate differently to specificity compared to early parts. This is relevant in the context of double training papers, which suggest that rule-based mechanisms of specificity in fast, early learning also would apply to late, slower learning. Our data showed partial but significant position and orientation specificity within quadrants. Interestingly, specificity was greatest for those participants who had continued to show threshold decreases during the last five sessions of training (late, asymptotic learning). Performance gains during early learning were less related to specificity. A trend for skill to spread over larger distances towards periphery than towards central vision suggested contributions to transfer of early visual areas showing cortical magnification of central vision. Control experiments however did not support this hypothesis. In summary, our study demonstrates significant specificity after extensive perceptual learning, and indicates that asymptotic learning recruits specific mechanisms that promote specificity, and that may not be recruited yet in early parts of the learning. The contributions of different mechanisms to early and late learning suggests that following these different learning periods, generalization relies on different principles and is subjected to different limits.
过去十年，人们对视觉技能学习特异性（或相反，泛化性）的基础机制出现了新的观点。在这里，我们在周边位置通过方位辨别范式训练参与者，以诱导位置和方位特异性，并测试其潜在机制。具体来说，我们旨在测试内象限的泛化空间梯度是否由皮层放大决定，这将表明视敏度可塑性有助于学习和特异性。此外，我们旨在测试与早期部分相比，学习的后期部分与特异性的关系是否不同。这在双训练论文的背景下很重要，这些论文表明，快速、早期学习中基于规则的特异性机制也适用于后期、较慢的学习。我们的数据显示了象限内部分但显著的位置和方位特异性。有趣的是，对于那些在最后五次训练中继续表现出阈值降低的参与者（晚期、渐近学习），特异性最大。早期学习中的表现增益与特异性的相关性较低。技能向周边扩散的距离比向中央视觉扩散的趋势表明，早期视觉区域对面部放大的中央视觉有贡献。然而，控制实验并不支持这一假设。总之，我们的研究表明，在广泛的感知学习后，存在显著的特异性，并且表明渐近学习招募了促进特异性的特定机制，而这些机制可能尚未在学习的早期部分招募。不同机制对早期和晚期学习的贡献表明，在经历了这些不同的学习阶段后，泛化依赖于不同的原则，并受到不同的限制。
