The Brain and Mind Research Institute, Sydney Medical School, The University of Sydney, 100 Mallett Street, Camperdown, NSW 2050, Australia.
Exp Brain Res. 2013 Aug;229(2):157-70. doi: 10.1007/s00221-013-3602-5. Epub 2013 Jun 19.
Previous studies have shown that the vestibular short-latency-evoked potential (VsEP) in response to the brief head acceleration stimulus is a compound action potential of neurons innervating the otolith organs. However, due to the lack of direct evidence, it is currently unclear whether the VsEP is primarily generated by the activity of utricular or saccular afferent neurons, or some mixture of the two. Here, we investigated the origin of the VsEP evoked by brief bone-conducted vibration pulses in guinea pigs, using selective destruction of the cochlea, semicircular canals (SCCs), saccule, or utricle, along with neural blockade with tetrodotoxin (TTX) application, and mechanical displacements of the surgically exposed utricular macula. To access each end organ, either a dorsal or a ventral surgical approach was used. TTX application abolished the VsEP, supporting the neurogenic origin of the response. Selective cochlear, SCCs, or saccular destruction had no significant effect on VsEP amplitude, whereas utricular destruction abolished the VsEP completely. Displacement of the utricular membrane changed the VsEP amplitude in a non-monotonic fashion. These results suggest that the VsEP evoked by BCV in guinea pigs represents almost entirely a utricular response. Furthermore, it suggests that displacements of the utricular macula may alter its response to bone-conduction stimuli.
先前的研究表明，对短暂头部加速刺激的前庭短潜伏期诱发电位（VsEP）是支配耳石器官的神经元的复合动作电位。然而，由于缺乏直接证据，目前尚不清楚 VsEP 主要是由前庭或球囊传入神经元的活动产生的，还是两者的某种混合。在这里，我们通过使用选择性破坏耳蜗、半规管（SCCs）、球囊或椭圆囊，以及应用河豚毒素（TTX）进行神经阻滞，以及对手术暴露的椭圆囊斑进行机械移位，来研究豚鼠在短暂骨导振动脉冲刺激下诱发的 VsEP 的起源。为了接近每个终末器官，使用了背侧或腹侧手术入路。TTX 的应用消除了 VsEP，支持了该反应的神经源性起源。选择性耳蜗、SCCs 或球囊的破坏对 VsEP 幅度没有显著影响，而椭圆囊的破坏则完全消除了 VsEP。椭圆囊膜的移位以非单调的方式改变了 VsEP 的幅度。这些结果表明，豚鼠的 BCV 诱发的 VsEP 几乎完全代表了椭圆囊的反应。此外，这表明椭圆囊斑的移位可能会改变其对骨导刺激的反应。
