Functional Neuroimaging Unit, Geriatric Institute Research Center and Department of Psychology, University of Montreal, 4565 Queen Mary, Montreal QC, Canada.
Neuroimage. 2010 Jan 1;49(1):694-702. doi: 10.1016/j.neuroimage.2009.08.055. Epub 2009 Sep 2.
The 'learning and performance' conundrum has for a long time puzzled the field of cognitive neuroscience. Deciphering the genuine functional neuroanatomy of motor sequence learning, among that of other skills, has thereby been hampered. The main caveat is that changes in neural activity that inherently accompany task practice may not only reflect the learning process per se, but also the basic motor implementation of improved performance. Previous research has attempted to control for a performance confound in brain activity by adopting methodologies that prevent changes in performance. However, blocking the expression of performance is likely to distort the very nature of the motor sequence learning process, and may thus represent a major confound in itself. In the present study, we postulated that both learning-dependent plasticity mechanisms and learning-independent implementation processes are nested within the relationship that exists between performance and brain activity. Functional magnetic resonance imaging (fMRI) was used to map brain responses in healthy volunteers while they either (a) learned a novel sequence, (b) produced a highly automatized sequence or (c) executed non-sequential movements matched for speed frequency. In order to dissociate between qualitatively distinct, but intertwined, relationships between performance and neural activity, our analyses focused on correlations between variations in performance and brain activity, and how this relationship differs or shares commonalities between conditions. Results revealed that activity in the putamen and contralateral lobule VI of the cerebellum most strongly correlated with performance during learning per se, suggesting their key role in this process. By contrast, activity in a parallel cerebellar network, as well as in motor and premotor cortical areas, was modulated by performance during learning and during one or both control condition(s), suggesting the primary contribution of these areas in motor implementation, either as a function or not of the sequential content of movements. Our findings thus highlight the multifaceted nature of the link between performance and brain activity, and suggest that different components of the striato-cortical and cerebello-cortical motor loops play distinct, but complementary, roles during early motor sequence learning.
长期以来，“学习和表现”的难题一直困扰着认知神经科学领域。因此，对运动序列学习的真正功能神经解剖学的破译，以及其他技能的破译，都受到了阻碍。主要的警告是，伴随着任务练习而固有地改变的神经活动不仅可能反映学习过程本身，还可能反映改善表现的基本运动执行。先前的研究试图通过采用防止表现变化的方法来控制大脑活动中的表现混杂。然而，阻止表现的表达可能会扭曲运动序列学习过程的本质，因此本身可能代表一个主要的混杂。在本研究中，我们假设学习相关的可塑性机制和学习独立的执行过程都嵌套在表现和大脑活动之间的关系中。功能磁共振成像（fMRI）用于在健康志愿者执行以下任务时绘制大脑反应：(a) 学习新序列，(b) 产生高度自动化的序列，或 (c) 以匹配速度频率执行非序列运动。为了区分表现和神经活动之间存在的不同但相互交织的关系，我们的分析重点是表现和大脑活动之间变化的相关性，以及这种关系在不同条件下如何不同或共享共同点。结果表明，在学习过程中，纹状体和对侧小脑 VI 叶的活动与表现最强烈相关，表明它们在该过程中的关键作用。相比之下，小脑平行网络以及运动和运动前皮质区域的活动在学习和一个或两个控制条件期间受到表现的调节，这表明这些区域在运动执行中的主要贡献，无论是作为运动顺序内容的函数还是不是。我们的研究结果因此强调了表现和大脑活动之间联系的多方面性质，并表明纹状体 - 皮质和小脑 - 皮质运动回路的不同成分在早期运动序列学习期间发挥着不同但互补的作用。
