Wohlert A B, Larson C R
Northwestern University, Evanston, IL.
J Speech Hear Res. 1991 Dec;34(6):1387-96. doi: 10.1044/jshr.3406.1387.
The "readiness potential" is an event-related potential that shows increasing negativity at vertex and motor strip scalp recording sites prior to voluntary, unilateral limb movements. Though speech involves movement on both sides of the midline, recent recordings of prespeech potentials suggest a pattern of bilateral activation that lateralizes to the dominant hemisphere just prior to the onset of articulatory movement. To determine whether this pattern of dominant hemisphere activation is present prior to a stereotyped, nonspeech movement of the mouth, the averaged potentials preceding a lip protrusion task were recorded at the cranial vertex and over the right and left motor cortex. Results were compared to potentials preceding a right finger extension task performed by the same subjects. Both the finger and the lip movements were initially preceded by slow negative potentials. Prior to the finger extension task, the negative amplitude became greatest over the left motor cortex, contralateral to the side of movement. Prior to the lip protrusion task, the amplitude of the potential remained even over the right and left motor cortices. The results suggest that, for this nonspeech movement of a midline structure, bilateral cortical control takes place. Control of lip movement is apparently not necessarily a dominant hemisphere function, though dominance may become part of the motor control strategy for more complex movements such as those used during speech.
“准备电位”是一种与事件相关的电位，在单侧肢体自主运动之前，在头顶和运动区头皮记录部位会显示出负电位增加。虽然言语涉及中线两侧的运动，但最近对言语前电位的记录表明，在发音运动开始前，双侧激活模式会向优势半球侧化。为了确定在口部定型的非言语运动之前是否存在这种优势半球激活模式，在颅顶以及左右运动皮层记录了唇部前突任务之前的平均电位。将结果与同一受试者进行右手手指伸展任务之前的电位进行比较。手指和唇部运动最初都有缓慢的负电位。在手指伸展任务之前，负电位幅度在运动对侧的左运动皮层上最大。在唇部前突任务之前，左右运动皮层上的电位幅度保持均匀。结果表明，对于中线结构的这种非言语运动，存在双侧皮层控制。唇部运动的控制显然不一定是优势半球的功能，尽管优势可能成为更复杂运动（如言语中使用的运动）的运动控制策略的一部分。
