Motor sequence learning with the nondominant left hand - A PET functional imaging study
Motor sequence learning with the nondominant left hand - A PET functional imaging study
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DOI：
10.1007/s00221-002-1181-y
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发表时间：
2002-10-01
影响因子：
2
通讯作者：
Ivry, RB
中科院分区：
文献类型：
--
作者：
Grafton, ST;Hazeltine, E;Ivry, RB
虽然人类的右半球在执行对侧手部运动时是活跃的，但左半球参与对侧和同侧运动，至少对于右手受试者来说是这样。这种不对称性是否也存在于运动学习过程中仍然未知。在功能性脑成像过程中通过串行反应时间（SRT）任务检查非优势左手的内隐序列学习。随着学习的进展，观察到左侧前运动皮层（PMC）和双侧辅助运动区（SMA）的大脑活动增加，其中左半球的增加明显更大。左侧 SMA 位点与之前通过右手学习识别的位点相似，表明该区域对于代表独立于效应器的序列至关重要。用左手学习还招募了一组广泛的颞叶和额叶区域，这表明用非惯用手学习运动技能是在认知和运动相关功能网络中发展的。获得技能后，受试者用右手执行 SRT 任务，并使用原始序列和镜像序列测试序列转移。与原始序列相比，刺激序列和一系列反应位置保持不变，但手指运动不同。对于镜像排序的序列，响应序列涉及与训练期间使用的手指运动相同的手指运动。右手的原始序列和镜像序列的表现明显优于随机刺激。右手序列的镜像变换与左运动皮层区域活动的显着增加相关，这与运动输出通路这一水平的顺序变换的作用一致。
Whereas the human right hemisphere is active during execution of contralateral hand movements, the left hemisphere is engaged for both contra- and ipsilateral movements, at least for right-handed subjects. Whether this asymmetry is also found during motor learning remains unknown. Implicit sequence learning by the nondominant left hand was examined with the serial reaction time (SRT) task during functional brain imaging. As learning progressed, increases in brain activity were observed in left lateral premotor cortex (PMC) and bilaterally in supplementary motor areas (SMA), with the increase significantly greater in the left hemisphere. The left SMA site was similar to one previously identified with right-hand learning, suggesting that this region is critical for representing a sequence independent of effector. Learning with the left hand also recruited a widespread set of temporal and frontal regions, suggesting that motor skill learning with the nondominant hand develops within both cognitive and motor-related functional networks. After skill acquisition, subjects performed the SRT task with their right hands, and sequence transfer was tested with the original and a mirror-ordered sequence. With the original sequence, the stimulus sequence and series of response locations remained unchanged, but the finger movements were different. With the mirror-ordered sequence, the response sequence involved finger movements homologous to those used during training. Performance of the original and mirror sequence by the right hand was significantly better than with random stimuli. Mirror transformation of the sequence by the right hand was associated with a marked increase in regional activity in the left motor cortex, consistent with a role for sequential transformation at this level of the motor output pathway.