Modification of planned actions
Modification of planned actions
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DOI：
10.1007/s00221-008-1584-5
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发表时间：
2009-01-01
影响因子：
2
通讯作者：
Gilbert, Sam J.
中科院分区：
文献类型：
--
作者：
Obhi, Sukhvinder S.;Matkovich, Shannon;Gilbert, Sam J.
为了阐明运动前修改计划行动的时间过程和过程，参与者准备在指定的时间窗口内自己选择的时间采取行动。在某些情况下，参与者准备进行单次右食指按键，而在其他情况下，他们准备进行由右食指按键和右中指按键组成的两次按键序列。在一部分试验中，他们的内部准备被一个听觉音调打断，作为回应，他们做出了以下两种选择之一：与他们预期的相同的动作，需要额外效应器的不同动作（即，从准备单个右食指按键切换到执行右食指、中指序列），或者需要少一个效应器的不同动作（即，从准备右食指、中指序列切换到执行右食指按键）。对于未修改的行动，从内部产生的外部触发模式的响应生产切换产生了显着的反应时间成本（RT成本）的单一和顺序的行动，与单一的行动的成本显着大于顺序的行动。鉴于RT成本没有增加的复杂性的行动增加，它是不可能的，成本的来源是与电机执行过程，它建议，它可能会出现在一个更高层次的认知阶段的处理。此外，反应时间产生修改的行动显着大于那些产生未修改的行动。最后，产生需要少一个效应器的修改动作比产生需要多一个效应器的修改动作花费的时间要长得多。我们建议，两个耗时的过程中涉及内部生成的和外部触发的动作之间的切换是修改或未修改的：触发开关成本时，同样的动作必须产生响应于外部触发器，而不是内部触发器，和开关成本反映的变化时，修改是必要的执行电机命令的模式。这表明，这种过程可能是由额叶区域介导的。
To elucidate the time course and processes underlying pre-movement modification of planned actions, participants prepared to make an action at a time of their own choosing within a specified temporal window. In some conditions, participants prepared to make a single right index finger key press, whereas in others, they prepared to make a sequence of two key presses consisting of a right index finger key press followed by a right middle finger key press. On a proportion of trials, their internal preparation was interrupted by an auditory tone, in response to which they made either: the same action as they were intending, a different action requiring an additional effector (i.e. switch from preparing a single right index finger key press to executing a right index, middle finger sequence), or a different action requiring one less effector (i.e. switch from preparing a right index, middle finger sequence to executing a right index finger key press). For unmodified actions, switching from an internally generated to an externally triggered mode of response production produced a significant reaction time cost (RT cost) for both single and sequential actions, with the cost for single actions being significantly greater than that for sequential actions. Given that the RT cost did not increase as the complexity of the actions increased it is unlikely that the source of the cost is related to motor execution processes, and it is suggested that it may arise at a higher level cognitive stage of processing. In addition, reaction times to produce modified actions were significantly greater than those to produce unmodified actions. Finally, it took significantly longer to produce modified actions requiring one less effector than to produce modified actions requiring one more effector. We suggest that two time-consuming processes are involved in switching between internally generated and externally triggered actions that are modified or unmodified: a trigger switch cost when the same action has to be produced in response to an external trigger as opposed to an internal trigger, and a switch cost reflecting changes in the pattern of executed motor commands when modification is necessary. It is suggested that such processes may be mediated by regions of the frontal lobes.