Neuroscience Research Australia and the University of New South Wales, Sydney, Australia.
Exp Brain Res. 2011 May;210(3-4):489-501. doi: 10.1007/s00221-010-2521-y. Epub 2010 Dec 29.
We characterized the three-dimensional angular vestibulo-ocular reflex (3D aVOR) of adult C57BL6 mice during static tilt testing, sinusoidal, and high-acceleration rotations and compared it with that of another lateral-eyed mammal with afoveate retinae (chinchilla) and two primate species with forward eye orientation and retinal foveae (human and squirrel monkey). Noting that visual acuity in mice is poor compared to chinchillas and even worse compared to primates, we hypothesized that the mouse 3D aVOR would be relatively low in gain (eye-velocity/head-velocity) compared to other species and would fall off for combinations of head rotation velocity and frequency for which peak-to-peak position changes fall below the minimum visual angle resolvable by mice. We also predicted that as in chinchilla, the mouse 3D aVOR would be more isotropic (eye/head velocity gain independent of head rotation axis) and better aligned with the axis of head rotation than the 3D aVOR of primates. In 12 adult C57BL6 mice, binocular 3D eye movements were measured in darkness during whole-body static tilts, 20-100°/s whole-body sinusoidal rotations (0.02-10 Hz) and acceleration steps of 3,000°/s² to a 150°/s plateau (dominant spectral content 8-12 Hz). Our results show that the mouse has a robust static tilt counter-roll response gain of 0.35 (eye-position Δ/head-position Δ) and mid-frequency aVOR gain (0.6-0.8), but relatively low aVOR gain for high-frequency sinusoidal head rotations and for steps of head rotation acceleration (~0.5). Due to comparatively poor static visual acuity in the mouse, a perfectly compensatory 3D aVOR would confer relatively little benefit during high-frequency, low-amplitude movements. Therefore, our data suggest that the adaptive drive for maintaining a compensatory 3D aVOR depends on the static visual acuity in different species. Like chinchillas, mice have a much more nearly isotropic 3D aVOR than do the primates for which comparable data are available. Relatively greater isotropy in lateral-eyed species without retinal foveae (e.g., mice and chinchillas in the present study) compared to forward-eyed species with retinal foveae (e.g., squirrel monkeys and humans) suggests that the parallel resting optic axes and/or radially symmetric retinal foveae of primates underlie their characteristically low 3D aVOR gain for roll head rotations.
我们描述了成年 C57BL6 小鼠在静态倾斜测试、正弦和高加速度旋转期间的三维角前庭眼反射（3D aVOR），并将其与另一种具有凹形视网膜的外侧眼哺乳动物（南美栗鼠）和两种具有向前眼定向和视网膜中央凹的灵长类物种（人 和松鼠猴）进行了比较。我们注意到，与南美栗鼠相比，小鼠的视力较差，甚至比灵长类动物更差，因此我们假设与其他物种相比，小鼠的 3D aVOR 增益（眼速/头速）相对较低，并且对于头旋转速度和频率的组合，峰值到峰值位置变化低于小鼠可分辨的最小视角。我们还预测，与南美栗鼠一样，小鼠的 3D aVOR 将更加各向同性（与头旋转轴无关的眼/头速度增益），并且与灵长类动物的 3D aVOR 相比，与头旋转轴的对齐更好。在 12 只成年 C57BL6 小鼠中，在黑暗中测量了整个身体静态倾斜、20-100°/s 整个身体正弦旋转（0.02-10 Hz）和 3000°/s² 的加速度步长到 150°/s 平台（主要频谱内容为 8-12 Hz）期间的双眼 3D 眼球运动。我们的结果表明，小鼠具有强大的静态倾斜反滚响应增益约为 0.35（眼位置 Δ/头位置 Δ）和中频 aVOR 增益（约 0.6-0.8），但对于高频正弦头旋转和头旋转加速度的阶跃，aVOR 增益相对较低（约 0.5）。由于小鼠的静态视觉敏锐度相对较差，因此在高频、低幅度运动中，完美的补偿性 3D aVOR 几乎没有带来好处。因此，我们的数据表明，维持补偿性 3D aVOR 的适应驱动力取决于不同物种的静态视觉敏锐度。与具有可比数据的灵长类动物相比，像南美栗鼠一样，小鼠具有更接近各向同性的 3D aVOR。在没有视网膜中央凹的外侧眼物种（例如，本研究中的小鼠和南美栗鼠）中，与具有视网膜中央凹的向前眼物种（例如，松鼠猴和人类）相比，相对更大的各向同性表明，灵长类动物的平行静止视轴和/或径向对称的视网膜中央凹是其特征性低 3D aVOR 滚头旋转增益的基础。
