Contribution of hand motor circuits to counting
Contribution of hand motor circuits to counting
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DOI：
10.1162/jocn.2007.19.4.563
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发表时间：
2007-04-01
影响因子：
3.2
通讯作者：
Olivier, Etienne
中科院分区：
文献类型：
--
作者：
Andres, Michael;Seron, Xavier;Olivier, Etienne
数字处理激活了一个部分重叠的皮层网络，该网络用于手部运动，这一发现重新引起了人们对数字和手指表征之间关系的兴趣。关于手指和数字之间可能存在联系的进一步证据来自发展研究，该研究表明手指的运动在学习数数方面起着至关重要的作用。然而，计数过程中手部运动回路的活动增加可能揭示了一些不特定的过程，如转移注意力、背诵数字名称或将物品与数字名称相匹配。为了解决这个问题，我们使用经颅磁刺激来测量在无声计数任务中使用数字或字母表中的字母枚举项目时皮质脊髓（CS）兴奋性的变化。我们发现，在计数任务中，无论使用数字或字母，手部肌肉的CS兴奋性都有所增加，而手臂和脚的肌肉则没有变化。控制任务允许Lis排除注意分配或隐蔽言语对计数过程中手部肌肉CS兴奋性增加的可能影响。目前的结果支持了手部运动回路在计数中的特殊参与，因为在相同的任务中，手臂和足部肌肉没有发现CS变化。然而，手运动区域的贡献并不仅仅与数字处理有关，因为当使用字母来列举项目时，也发现了CS兴奋性的增加。这一发现表明，只要项目必须与任何有序系列的元素相对应，就涉及到手动电机电路。
The finding that number processing activates a cortical network partly overlapping that recruited for hand movements has renewed interest in the relationship between number and finger representations. Further evidence about a possible link between fingers and numbers comes from developmental studies showing that finger movements play a crucial role in learning counting. However, increased activity in hand motor circuits during counting may unveil unspecific processes, such as shifting attention, reciting number names, or matching items with a number name. TO address this issue, we used transcranial magnetic Stimulation to measure changes in corticospinal (CS) excitability during a counting task performed silently and using either numbers or letters of the alphabet to enumerate items. We found an increased CS excitability of hand muscles during the counting task, irrespective Of the use of numbers or letters, whereas it was unchanged in arm and foot muscles. Control tasks allowed Lis to rule out a possible influence of attention allocation or covert speech on CS excitability increase of hand muscles during counting. The present results support a specific involvement of hand motor circuits in counting because no CS changes were found in arm and foot muscles during the same task. However, the contribution of hand motor areas is not exclusively related to number proccssing because an increase in CS excitability was also found when letters were used to enumerate items. This finding suggests that hand motor circuits are involved whenever items have to be put in correspondence with the elements of any ordered series.