Calabro Finnegan J, Rana Kunjan D, Vaina Lucia M
Brain and Vision Research Laboratory, Department of Biomedical Engineering, Boston University, Boston, MA 02134, USA.
J Vis. 2011 Mar 8;11(3):10.1167/11.3.5 5. doi: 10.1167/11.3.5.
The detection of looming, the motion of objects in depth, underlies many behavioral tasks, including the perception of self-motion and time-to-collision. A number of studies have demonstrated that one of the most important cues for looming detection is optic flow, the pattern of motion across the retina. Schrater et al. have suggested that changes in spatial frequency over time, or scale changes, may also support looming detection in the absence of optic flow (P. R. Schrater, D. C. Knill, & E. P. Simoncelli, 2001). Here we used an adaptation paradigm to determine whether the perception of looming from optic flow and scale changes is mediated by single or separate mechanisms. We show first that when the adaptation and test stimuli were the same (both optic flow or both scale change), observer performance was significantly impaired compared to a dynamic (non-motion, non-scale change) null adaptation control. Second, we found no evidence of cross-cue adaptation, either from optic flow to scale change, or vice versa. Taken together, our data suggest that optic flow and scale changes are processed by separate mechanisms, providing multiple pathways for the detection of looming.
对逼近的检测，即物体在深度上的运动，是许多行为任务的基础，包括对自身运动和碰撞时间的感知。大量研究表明，逼近检测最重要的线索之一是光流，即视网膜上的运动模式。施拉特等人提出，随着时间推移空间频率的变化，即尺度变化，在没有光流的情况下也可能有助于逼近检测（P.R.施拉特、D.C.尼尔和E.P.西蒙切利，2001年）。在此，我们使用适应范式来确定光流和尺度变化所引起的逼近感知是由单一机制还是由不同机制介导的。我们首先表明，当适应刺激和测试刺激相同时（光流或尺度变化两者皆同），与动态（非运动、非尺度变化）零适应对照相比，观察者的表现显著受损。其次，我们没有发现交叉线索适应的证据，无论是从光流到尺度变化，还是反之亦然。综合来看，我们的数据表明光流和尺度变化是由不同机制处理的，为逼近检测提供了多种途径。
