Department of Anatomy, University of California, San Francisco, San Francisco, United States.
Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States.
Elife. 2021 Dec 31;10:e73081. doi: 10.7554/eLife.73081.
Animals investigate their environments by directing their gaze towards salient stimuli. In the prevailing view, mouse gaze shifts entail head rotations followed by brainstem-mediated eye movements, including saccades to reset the eyes. These 'recentering' saccades are attributed to head movement-related vestibular cues. However, microstimulating mouse superior colliculus (SC) elicits directed head and eye movements resembling SC-dependent sensory-guided gaze shifts in other species, suggesting that mouse gaze shifts may be more flexible than has been recognized. We investigated this possibility by tracking eye and attempted head movements in a head-fixed preparation that eliminates head movement-related sensory cues. We found tactile stimuli evoke directionally biased saccades coincident with attempted head rotations. Differences in saccade endpoints across stimuli are associated with distinct stimulus-dependent relationships between initial eye position and saccade direction and amplitude. Optogenetic perturbations revealed SC drives these gaze shifts. Thus, head-fixed mice make sensory-guided, SC-dependent gaze shifts involving coincident, directionally biased saccades and attempted head movements. Our findings uncover flexibility in mouse gaze shifts and provide a foundation for studying head-eye coupling.
动物通过注视显著刺激来探索它们的环境。在主流观点中，老鼠的注视转移需要头部旋转，然后是脑干介导的眼球运动，包括扫视以重新定位眼睛。这些“重新定位”扫视归因于与头部运动相关的前庭线索。然而，刺激老鼠上丘（SC）会引发类似于其他物种中 SC 依赖的感觉引导性注视转移的定向头部和眼球运动，这表明老鼠的注视转移可能比之前认为的更加灵活。我们通过在消除头部运动相关感觉线索的头部固定装置中跟踪眼睛和尝试头部运动来研究这种可能性。我们发现触觉刺激会引发与尝试头部旋转一致的定向扫视。不同刺激之间的扫视终点差异与初始眼位和扫视方向和幅度之间的独特刺激依赖性关系相关。光遗传学扰动显示 SC 驱动这些注视转移。因此，头部固定的老鼠会进行感觉引导的、SC 依赖的注视转移，涉及一致的、定向性的扫视和尝试性的头部运动。我们的发现揭示了老鼠注视转移的灵活性，并为研究头眼耦合提供了基础。
