Newlands S D, Perachio A A
Department of Otolaryngology, University of Texas Medical Branch, Galveston 77550.
Exp Brain Res. 1990;82(2):373-83. doi: 10.1007/BF00231256.
The spontaneous activity and dynamic responses to sinusoidal horizontal head angular acceleration of type II horizontal semicircular canal related neurons in the medial vestibular nucleus (MVN) were recorded bilaterally in decerebrate Mongolian gerbils (Meriones unguiculatus) under three experimental conditions: normal labyrinths intact, acutely following unilateral labyrinthine lesion, and four to seven weeks following labyrinthine lesion. The number of type II neurons detected contralateral to the lesion was greatly reduced both in the acutely hemilabyrinthectomized animals and following compensation. The gain of the responses was depressed bilaterally acutely following the lesion. A greater reduction in response gain was noted in cells contralateral to the lesion. The gain of the contralateral type II responses increased with time such that in the compensated animal bilaterally symmetric gains were recorded. While the significant changes which occur in the gain of type II neurons with recovery from peripheral vestibular lesions can largely be attributed to type I neurons on the other side of the midline, changes in type I neurons were not entirely reflected in the type II population. The spontaneous activity of type II neurons did not undergo any significant changes following the labyrinthine lesion. We present a model utilizing the dynamic responses to estimate the functional recovery of commissural connections in compensated animals. The overall gain of the contralateral type I to ipsilateral type I commissural polysynaptic pathway appears to improve, while the efficacy in the reverse direction remains depressed, suggesting that modifications in commissural connections, particularly involving the type II to type I connections within the MVN on the injured side, mediate aspects of behavioral recovery.
在内耳迷路正常完整、单侧迷路急性损伤后以及迷路损伤后4至7周这三种实验条件下，对去大脑蒙古沙鼠（长爪沙鼠）双侧内侧前庭核（MVN）中与II型水平半规管相关神经元的自发活动以及对正弦水平头部角加速度的动态反应进行了记录。在急性半规管切除动物和补偿后，损伤对侧检测到的II型神经元数量大幅减少。损伤后双侧反应增益急性降低。损伤对侧细胞的反应增益降低更为明显。对侧II型反应的增益随时间增加，以至于在补偿动物中记录到双侧对称的增益。虽然随着外周前庭损伤恢复，II型神经元增益发生的显著变化在很大程度上可归因于中线另一侧的I型神经元，但I型神经元的变化并未完全反映在II型群体中。II型神经元的自发活动在迷路损伤后未发生任何显著变化。我们提出了一个利用动态反应来估计补偿动物中连合连接功能恢复的模型。对侧I型到同侧I型连合多突触通路的总体增益似乎有所改善，而反向方向的效能仍然降低，这表明连合连接的改变，特别是涉及损伤侧MVN内II型到I型连接的改变，介导了行为恢复的各个方面。
