Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata 951-8514, Japan.
Neurosci Lett. 2012 Oct 24;528(2):159-64. doi: 10.1016/j.neulet.2012.09.005. Epub 2012 Sep 13.
To clarify the functional role of cortical descending inputs involved in the swallowing reflex, the effect of electrical stimulation of two cortical masticatory areas (CMAs: A- and P-area) on rhythmic jaw movements (RJMs) and superior laryngeal nerve (SLN)-evoked swallows were studied. RJMs and swallowing reflex were elicited by repetitive electrical stimulation of CMAs and the SLN, respectively. The electromyographic activities of jaw-closer (masseter), jaw-opener (digastric), and laryngeal-elevator (thyrohyoid) muscles were recorded to identify the RJMs and swallowing reflex. The number of evoked swallows was significantly lower, and swallowing interval was significantly longer during A-area stimulation compared with those without stimulation. Conversely, these parameters were not significantly altered during P-area stimulation. The inhibition of swallows by A-area stimulation was not affected by an increase in sensory input by wooden stick application between upper and lower teeth, or A-area stimulation preceding SLN stimulation. The present findings suggest that the swallowing reflex is inhibited by activation of the A-area, but not the P-area. Since no changes in swallows were seen after the increase in intraoral sensory input and prior activation of masticatory central pattern generator (CPG), swallowing inhibition may be mediated by direct inputs from the A-area or inputs via the masticatory CPG into the swallowing CPG.
为了阐明参与吞咽反射的皮质下行传入的功能作用，研究了电刺激两个皮质咀嚼区（CMAs：A 区和 P 区）对节律性下颌运动（RJM）和喉上神经（SLN）诱发的吞咽的影响。通过对 CMAs 和 SLN 的重复电刺激分别诱发 RJM 和吞咽反射。记录了颌闭肌（咬肌）、颌开肌（二腹肌）和喉提升肌（甲状舌骨肌）的肌电活动，以识别 RJM 和吞咽反射。与无刺激相比，A 区刺激时诱发的吞咽次数明显减少，吞咽间隔明显延长。相反，在 P 区刺激期间，这些参数没有明显改变。A 区刺激对吞咽的抑制作用不受上下牙之间木片应用增加感觉输入或 A 区刺激先于 SLN 刺激的影响。本研究结果表明，A 区的激活抑制了吞咽反射，但 P 区没有。由于在增加口腔内感觉输入和咀嚼中枢模式发生器（CPG）预先激活后，吞咽没有变化，因此吞咽抑制可能是由 A 区的直接输入或通过咀嚼 CPG 传入吞咽 CPG 的输入介导的。
