Scheerer N E, Jacobson D S, Jones J A
Psychology Department, Wilfrid Laurier University, Waterloo, Ontario, Canada; Laurier Centre for Cognitive Neuroscience, Wilfrid Laurier University, Waterloo, Ontario, Canada.
Psychology Department, Wilfrid Laurier University, Waterloo, Ontario, Canada; Laurier Centre for Cognitive Neuroscience, Wilfrid Laurier University, Waterloo, Ontario, Canada.
Neuroscience. 2016 Feb 9;314:106-15. doi: 10.1016/j.neuroscience.2015.11.037. Epub 2015 Nov 28.
Auditory feedback plays an important role in the acquisition of fluent speech; however, this role may change once speech is acquired and individuals no longer experience persistent developmental changes to the brain and vocal tract. For this reason, we investigated whether the role of auditory feedback in sensorimotor learning differs across children and adult speakers. Participants produced vocalizations while they heard their vocal pitch predictably or unpredictably shifted downward one semitone. The participants' vocal pitches were measured at the beginning of each vocalization, before auditory feedback was available, to assess the extent to which the deviant auditory feedback modified subsequent speech motor commands. Sensorimotor learning was observed in both children and adults, with participants' initial vocal pitch increasing following trials where they were exposed to predictable, but not unpredictable, frequency-altered feedback. Participants' vocal pitch was also measured across each vocalization, to index the extent to which the deviant auditory feedback was used to modify ongoing vocalizations. While both children and adults were found to increase their vocal pitch following predictable and unpredictable changes to their auditory feedback, adults produced larger compensatory responses. The results of the current study demonstrate that both children and adults rapidly integrate information derived from their auditory feedback to modify subsequent speech motor commands. However, these results also demonstrate that children and adults differ in their ability to use auditory feedback to generate compensatory vocal responses during ongoing vocalization. Since vocal variability also differed across the children and adult groups, these results also suggest that compensatory vocal responses to frequency-altered feedback manipulations initiated at vocalization onset may be modulated by vocal variability.
听觉反馈在流利言语的习得中起着重要作用；然而，一旦言语习得，且个体不再经历大脑和声道持续的发育变化，这一作用可能会改变。因此，我们研究了听觉反馈在感觉运动学习中的作用在儿童和成年说话者中是否存在差异。参与者在听到自己的音高可预测或不可预测地下降一个半音时发出声音。在每次发声开始时，在可获得听觉反馈之前，测量参与者的音高，以评估异常听觉反馈对后续言语运动指令的修改程度。在儿童和成年人中均观察到感觉运动学习，参与者在接触到可预测而非不可预测的频率改变反馈的试验后，其初始音高会增加。还在每次发声过程中测量参与者的音高，以确定异常听觉反馈用于修改正在进行的发声的程度。虽然发现儿童和成年人在听觉反馈发生可预测和不可预测变化后都会提高音高，但成年人产生的补偿反应更大。当前研究的结果表明，儿童和成年人都会迅速整合来自听觉反馈的信息，以修改后续的言语运动指令。然而，这些结果也表明，儿童和成年人在利用听觉反馈在发声过程中产生补偿性发声反应的能力上存在差异。由于儿童和成年组的发声变异性也不同，这些结果还表明，对发声开始时频率改变反馈操作的补偿性发声反应可能会受到发声变异性的调节。
