Brainstem mechanisms of otolith-visual interaction in the control of eye movement produced by sinusoidal vertical linear acceleration

在0.20 ~ 0.85 hz、振幅为10.5cm（对应0.02 ~ 0.31g）的正弦垂直线性加速度条件下，观察眼动反应。光下的正弦线性加速在所有测试的刺激频率下都产生了接近补偿阶段的强健眼动反应。然而，在黑暗中，只有少量的晚期反应（通过70个单位）被获得。随着刺激频率的增加，光动力刺激产生的反应相位滞后更大，增益更小。在接受双侧迷路切除术的猫中，线性加速导致在更高的刺激频率下相位滞后更大，在所有测试频率下增益下降。这些结果表明，耳石和视觉输入的相互作用产生了强大的眼动反应，在光的正弦线性加速过程中具有近补偿阶段。为了研究这种相互作用的脑干机制，我们在Cajal （INC）和前庭核（VN）的间质核中记录了神经元的活动。眼内所有眼动相关的突发性强直（BT）和强直(T)神经元的活动与光下的眼动反应相关。然而，在黑暗中，大多数人（84%）没有回应。其余细胞对线性加速度有反应；与光中的响应相比，它们的平均相位值提高了801，增益下降了55%。这些结果表明，耳石-视觉相互作用发生在这些神经元水平之前。除了BT和T细胞外，许多INC细胞在黑暗和光动力刺激下对线性加速度有反应，表明这些细胞接受了耳石和视觉输入。其中一些细胞在光线下线性加速时的反应可以通过耳石和视觉输入的增加来解释。许多视神经细胞对俯仰旋转有反应，包括对眼睛垂直位置敏感的细胞，在黑暗中对线性加速度没有反应。少数VN细胞在黑暗中对线性加速有反应。这些结果表明，耳石-视觉相互作用可能发生在不具有眼位敏感性的INC和VN神经元上。少

Eye movement responses were examined in alert during sinusoidal vertical linear acceleration at 0.20-0.85Hz with an amplitude of 10.5cm (corresponding to 0.02-0.31g). Sinusoidal linear acceleration in the light produced robust eye movement responses with near compensatory phase at all stimulus frequencies tested. In the dark, however, only small responses with advanced phase (by 70ﾟ) were obtained. Optokinetic stimulation alone produced more lag of response phase with smaller gain as stimulus frequency increased. Linear acceleration in cats that had received bilateral labyrinthectomies resulted in more phase lag at higher stimulus frequencies and decreased gain at all frequencies tested. These results indicate that the interaction of otolith and visual inputs produces robust eye movement responses with near compensatory phase during sinusoidal linear acceleration in the light.To examine brainstem mechanisms for this interaction, neuronal activity was recorded in the interstitial nucleu … More s of Cajal (INC) and vestibular nuclei (VN). Activity of all eye movement-related burst-tonic (BT) and tonic (T) neurons in the INC was modulated in correlation to eye movement responses in the light. However, in the dark, most of them (84%) did not respond. The remaining cells responded to linear acceleration ; their mean phase values advanced by 801 and gain dropped by 55% compared to the responses in the light. These results suggest that the otolith-visual interaction occurs before the level of these neurons. Many INC cells other than BT and T cells responded to linear acceleration in the dark and optokinetic stimulation, indicating that these cells received otolith and visual inputs. Responses of some of these cells during linear acceleration in the light could be explained by addition of otolith and visual inputs. Many VN cells that responded to pitch rotation, including cells with vertical eye position sensitivity, did not respond to linear acceleration in the dark. A minority of VN cells responded to linear acceleration in the dark. These results suggest that the otolith-visual interaction may occur both in the INC and VN at neurons that do not have eye position sensitivity. Less