Rosengren Sally M, Weber Konrad P, Govender Sendhil, Welgampola Miriam S, Dennis Danielle L, Colebatch James G
Neurology Department, Royal Prince Alfred Hospital, Camperdown, Australia.
Central Clinical School, University of Sydney , Sydney , Australia.
J Appl Physiol (1985). 2019 Jun 1;126(6):1619-1629. doi: 10.1152/japplphysiol.00711.2018. Epub 2019 Mar 28.
The short-latency vestibulo-collic reflex in humans is well defined for only the sternocleidomastoid (SCM) neck muscle. However, other neck muscles also receive input from the balance organs and participate in neck stabilization. We therefore investigated the sound-evoked vestibular projection to the splenius capitis (SC) muscles by comparing surface and single motor unit responses in the SC and SCM muscles in 10 normal volunteers. We also recorded surface responses in patients with unilateral vestibular loss but preserved hearing and hearing loss but preserved vestibular function. The single motor unit responses were predominantly inhibitory, and the strongest responses were recorded in the contralateral SC and ipsilateral SCM. In both cases there was a significant decrease or gap in single motor unit activity, in SC at 11.7 ms for 46/66 units and in SCM at 12.7 ms for 51/58 motor units. There were fewer significant responses in the ipsilateral SC and contralateral SCM muscles, and they consisted primarily of weak increases in activity. Surface responses recorded over the contralateral SC were positive-negative during neck rotation, similar to the ipsilateral cervical vestibular evoked myogenic potential in SCM. Responses in SC were present in the patients with hearing loss and absent in the patient with vestibular loss, confirming their vestibular origin. The results describe a pattern of inhibition consistent with the synergistic relationship between these muscles for axial head rotation, with the crossed vestibular projection to the contralateral SC being weaker than the ipsilateral projection to the SCM. We used acoustic vestibular stimulation to investigate the saccular projections to the splenius capitis (SC) and sternocleidomastoid (SCM) muscles in humans. Single motor unit recordings from within the muscles demonstrated strong inhibitory projections to the contralateral SC and ipsilateral SCM muscles and weak excitatory projections to the opposite muscle pair. This synergistic pattern of activation is consistent with a role for the reflex in axial rotation of the head.
人类的短潜伏期前庭 - 颈反射仅在胸锁乳突肌（SCM）颈部肌肉中得到明确界定。然而，其他颈部肌肉也接收来自平衡器官的输入并参与颈部稳定。因此，我们通过比较10名正常志愿者的头夹肌（SC）和SCM肌肉的表面反应和单个运动单位反应，研究了声音诱发的前庭投射到头夹肌（SC）肌肉的情况。我们还记录了单侧前庭丧失但听力保留以及听力丧失但前庭功能保留的患者的表面反应。单个运动单位反应主要为抑制性，最强反应记录在对侧SC和同侧SCM中。在这两种情况下，单个运动单位活动均有显著下降或间隙，在SC中，46/66个单位在11.7毫秒时出现，在SCM中，51/58个运动单位在12.7毫秒时出现。同侧SC和对侧SCM肌肉中的显著反应较少，主要表现为活动的微弱增加。在对侧SC上记录的表面反应在颈部旋转时为正负波，类似于同侧SCM中的颈前庭诱发肌源性电位。听力丧失患者的SC中有反应，前庭丧失患者的SC中无反应，证实了它们的前庭起源。结果描述了一种与这些肌肉在轴向头部旋转中的协同关系一致的抑制模式，交叉前庭投射到对侧SC比同侧投射到SCM弱。我们使用听觉前庭刺激来研究人类球囊投射到头夹肌（SC）和胸锁乳突肌（SCM）肌肉的情况。肌肉内的单个运动单位记录显示对侧SC和同侧SCM肌肉有强烈的抑制性投射，对相反肌肉对有微弱的兴奋性投射。这种协同激活模式与该反射在头部轴向旋转中的作用一致。
