Specialized neural systems underlying representations of sequential movements
Specialized neural systems underlying representations of sequential movements
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DOI：
10.1162/08989290051137602
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发表时间：
2000-01-01
影响因子：
3.2
通讯作者：
Cox, RW
中科院分区：
文献类型：
--
作者：
Harrington, DL;Rao, SM;Cox, RW
动作组合成熟练动作的难易程度取决于许多因素，包括动作序列的复杂性。复杂性可以通过序列的表面结构来定义，包括运动特性，例如效应器的类型，以及抽象或序列特定的结构，这在运动之间的关系中是显而易见的，例如重复。目前尚不清楚不同的神经系统是否支持认知和感觉运动过程的不同结构特性的顺序行动。我们使用全脑功能磁共振成像（FMRI）对健康成年人进行了调查，因为他们执行了涉及多达三个手指的五个按键序列。序列的结构由两个因素定义，这两个因素独立地延长了在运动之前计划序列的时间：不同手指的数量（1-3;表面结构）和手指转换的数量（0-4;序列特异性结构）。结果表明，系统参与视觉处理（外纹皮层）和准备的传感器方面的运动（喙下顶叶和腹侧运动前皮层（PMV））与序列结构的两个属性。不同手指的数量与小脑和上级顶叶皮层（前部）的激活强度呈正相关，分别与感觉运动和运动学表示相关。手指转换的数量与先前与序列特异性处理相关的系统中的激活相关，包括下顶叶和背侧运动前皮层（PMD），以及相互连接的上级颞中回网络。左右下顶叶皮层的不同激活模式与不同的序列相关，这与序列使用不同的记忆术编码的推测一致，这取决于序列特定的结构。与此相反，PMD激活正相关的数量增加的过渡，这与该地区的作用，在检索或准备的抽象行动计划。这些研究结果表明，表面和序列特定结构的顺序运动可以区分不同的分布式系统，支持其潜在的心理操作。
The ease by which movements are combined into skilled actions depends on many factors, including the complexity of movement sequences. Complexity can be defined by the surface structure of a sequence, including motoric properties such as the types of effecters, and by the abstract or sequence-specific structure, which is apparent in the relations amongst movements, such as repetitions. It is not known whether different neural systems support the cognitive and the sensorimotor processes underlying different structural properties of sequential actions. We investigated this question using whole-brain functional magnetic resonance imaging (FMRI) in healthy adults as they performed sequences of five key presses involving up to three fingers. The structure of sequences was defined by two factors that independently lengthen the time to plan sequences before movement: the number of different fingers (1-3; surface structure) and the number of finger transitions (0-4; sequence-specific structure). The results showed that systems involved in visual processing (extrastriate cortex) and the preparation of sensor aspects of movement (rostral inferior parietal and, ventral premotor cortex (PMv)) correlated with both properties of sequence structure. The number of different fingers positively correlated with activation intensity in the cerebellum and superior parietal cortex (anterior), systems associated with sensorimotor, and kinematic representations of movement, respectively. The number of finger transitions correlated with activation in systems previously associated with sequence-specific processing, including the inferior parietal and the dorsal premotor cortex (PMd), and in interconnecting superior temporal-middle frontal gyrus networks. Different patterns of activation in the left and right inferior parietal cortex were associated with different sequences, consistent with the speculation that sequences are encoded using different mnemonics, depending on the sequence-specific structure. In contrast, PMd activation correlated positively with increases in the number of transitions, consistent with the role of this area, in the retrieval or preparation of abstract action plans. These findings suggest that the surface and the sequence-specific structure of sequential movements can be distinguished by distinct distributed systems that support their underlying mental operations.