Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB T1K 3M4, Canada; Neuro-Electronics Research Flanders, Kapeldreef 75, Leuven 3001, Belgium.
Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB T1K 3M4, Canada.
Curr Biol. 2020 May 4;30(9):1680-1688.e4. doi: 10.1016/j.cub.2020.02.070. Epub 2020 Mar 19.
The retrosplenial cortex (RSC) is involved in a broad range of cognitive functions, integrating rich sensory, motor, and spatial signals from multiple brain areas, including the hippocampal system. RSC neurons show hippocampus-dependent activity reminiscent of place cell sequences. Using cellular calcium imaging in a virtual reality (VR)-based locomotion task, we investigate how the integration of visual and locomotor inputs may give rise to such activity in RSC. A substantial population shows neural sequences that track position in the VR environment. This activity is driven by the conjunction of visual stimuli sequences and active movement, which is suggestive of path integration. The activity is anchored to a reference point and predominantly follows the VR upon manipulations of optic flow against locomotion. Thus, locomotion-gated optic flow, combined with the presence of contextual cues at the start of each trial, is sufficient to drive the sequential activity. A subpopulation shows landmark-related visual responses that are modulated by animal's position in the VR. Thus, rather than fragmenting the spatial representation into equivalent locomotion-based ensemble versus optic-flow-based ensemble, in RSC, optic flow appears to override locomotion signals coherently in the population, when the gain between the two signals is altered.
后扣带皮层（RSC）参与广泛的认知功能，整合来自多个脑区的丰富感觉、运动和空间信号，包括海马体系统。RSC 神经元表现出类似于位置细胞序列的海马体依赖性活动。我们使用基于虚拟现实 (VR) 的运动任务中的细胞钙成像来研究视觉和运动输入的整合如何导致 RSC 中出现这种活动。大量神经元显示出可跟踪 VR 环境中位置的神经序列。这种活动是由视觉刺激序列和主动运动的结合驱动的，这表明存在路径整合。当 VR 中的光流相对于运动发生变化时，该活动以参考点为锚定点，并且主要遵循 VR。因此，运动门控光流，加上每次试验开始时存在上下文线索，足以驱动序列活动。一部分神经元表现出与地标相关的视觉反应，这些反应受到动物在 VR 中位置的调制。因此，在 RSC 中，当两个信号之间的增益发生变化时，光流似乎不是将空间表示分割成基于运动的集合与基于光流的集合，而是在群体中一致地覆盖运动信号。
