Doykos Ted K, Yamauchi Taylor, Buteau Anna, Hanson Spencer, Dudman Joshua T, Felsen Gidon, Stubblefield Elizabeth A
Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA.
Neuroscience Program, University of Colorado School of Medicine, Aurora, CO 80045.
bioRxiv. 2025 May 8:2025.05.02.651955. doi: 10.1101/2025.05.02.651955.
Orienting movements are a critical component of the natural behavioral repertoire, but their underlying neural bases are not well understood. The deep superior colliculus (dSC) integrates input from several brain regions that influence the selection of targets for orienting movements and coordinates activity among brainstem motor nuclei to initiate and execute movement. Evidence suggests that one prominent dSC input, the substantia nigra (SNr), permits movement by disinhibiting its targets, but much is unknown about the relationship between SNr activity, dSC activity, and movement. Building on increasing application of the head-fixed mouse model to elucidate the neural basis of behavior, we examined neural activity recorded in dSC and SNr with high-density probes in mice performing several variants of a sensorimotor orienting task, from our labs and in data sets curated by the International Brain Laboratory. We found that dSC and SNr were active preceding and throughout movement, across task variants, suggesting that they were engaged by the required movements. Prior to movement, SNr activity reflected the outcome of the previous trial, consistent with a role in biasing movements towards the highest value target. However, the dependence of dSC activity on movement direction was weaker than in other directional orienting behaviors, and we found little evidence for strong suppression of dSC by SNr. These results complement and extend previous findings from other orienting tasks and suggest diverse roles for modulatory input from SNr to dSC in shaping motor behavior.
定向运动是自然行为库的关键组成部分，但其潜在的神经基础尚未得到充分理解。深层上丘（dSC）整合来自多个脑区的输入，这些输入影响定向运动目标的选择，并协调脑干运动核之间的活动以启动和执行运动。有证据表明，dSC的一个重要输入——黑质（SNr），通过解除对其目标的抑制来允许运动，但关于SNr活动、dSC活动和运动之间的关系仍有许多未知之处。基于头部固定小鼠模型在阐明行为神经基础方面的应用不断增加，我们在执行感觉运动定向任务的多个变体的小鼠中，使用高密度探针检查了dSC和SNr中记录的神经活动，这些任务来自我们实验室以及国际脑实验室整理的数据集。我们发现，在整个运动过程中，dSC和SNr在运动之前及整个过程中都是活跃的，跨越任务变体，这表明它们参与了所需的运动。在运动之前，SNr活动反映了前一次试验的结果，这与偏向最高价值目标的运动中的作用一致。然而，dSC活动对运动方向的依赖性比其他定向行为中的要弱，并且我们几乎没有发现SNr对dSC有强烈抑制作用的证据。这些结果补充并扩展了先前其他定向任务的研究结果，并表明SNr向dSC的调节性输入在塑造运动行为中具有多种作用。
