Our brain uses visual flow patterns to derive important information about the rotation of the eye and head through space and the direction of self-motion. This information is processed in various regions along the visual hierarchy, some of which also receive non-visual signals. Several regions along the dorsal stream are selective for elementary motion, like area V3A, V6 and the middle temporal area (MT). Other areas in this path, like the medial superior temporal area (MST) and the ventral intra-parietal area (VIP), are particularly modulated by optic-flow patterns. They are closely involved in heading perception and are both modulated by vestibular and eye movement signals. Although most of these higher visual areas have been retinotopically mapped, their functional role is still poorly understood. Previously, we have identified a sub-region of pMST, to be modulated by visual flow signals corresponding to a rotation of the head. For this, we used stimuli that allowed dissociation between simulated head- and gaze rotation (see abstract: van den Berg et al.). Here, we show -using psychophysical techniques, high-resolution functional resonance imaging and wide-field visual stimuli- that: (1) perceived ego-rotation corresponds to the simulated head rotation rather than the gaze rotation. (2) like in pMST, regions within area V3A, V6 and pVIP show a specific modulation of the BOLD response to simulated head rotation. (3) these areas have a retinotopic organization. Our observations do not permit us to conclude in which reference frame the receptive fields collect the visual flow: retino-centric or head-centric? Possibly the multiple visual representations of head-rotation differ in this respect.
展开▼
机译：我们的大脑使用视觉流动模式来获取有关眼睛和头部在空间中的旋转以及自我运动方向的重要信息。沿视觉层次结构在各个区域中处理此信息，其中一些区域还接收非视觉信号。沿背流的几个区域对基本运动具有选择性，例如区域V3A，V6和中间颞部区域（MT）。该路径中的其他区域，例如内侧颞上区域（MST）和腹侧顶内区域（VIP），尤其是由光流模式调制的。它们紧密参与航向感知，并且都受到前庭和眼睛运动信号的调制。尽管大多数这些较高的视觉区域已在视网膜上进行了制图，但对其功能的作用仍知之甚少。以前，我们已经确定了pMST的一个子区域，该子区域将由对应于头部旋转的视觉流信号进行调制。为此，我们使用了允许模拟的头部旋转和凝视旋转分离的刺激（见摘要：van den Berg等）。在这里，我们展示-使用心理物理技术，高分辨率功能共振成像和宽视野视觉刺激-（1）感知到的自我旋转对应于模拟的头部旋转而不是凝视旋转。 （2）像在pMST中一样，区域V3A，V6和pVIP内的区域显示了对模拟头部旋转的BOLD响应的特定调制。 （3）这些区域有视网膜组织。我们的观察结果不允许我们得出以下结论：感受野在哪个参考系中收集视觉流：以视网膜为中心还是以头部为中心？头部旋转的多种视觉表示可能在这方面有所不同。
展开▼
