School of Psychological Science, La Trobe University, Melbourne, Australia.
Behav Brain Funct. 2011 Aug 16;7:34. doi: 10.1186/1744-9081-7-34.
Although the ventral visual stream is understood to be responsible for object recognition, it has been proposed that the dorsal stream may contribute to object recognition by rapidly activating parietal attention mechanisms, prior to ventral stream object processing.
To investigate the relative contribution of the dorsal visual stream to object recognition a group of tertiary students were divided into good and poor motion coherence groups and assessed on tasks classically assumed to rely on ventral stream processing. Participants were required to identify simple line drawings in two tasks, one where objects were presented abruptly for 50 ms followed by a white-noise mask, the other where contrast was linearly ramped on and off over 325 ms and replaced with a mask.
Although both groups only differed in motion coherence performance (a dorsal stream measure), the good motion coherence group showed superior contrast sensitivity for object recognition on the abrupt, but not the ramped presentation tasks.
We propose that abrupt presentation of objects activated attention mechanisms fed by the dorsal stream, whereas the ramped presentation had reduced transience and thus did not activate dorsal attention mechanisms as well. The results suggest that rapid dorsal stream activation may be required to assist with ventral stream object processing.
尽管腹侧视觉流被认为负责对象识别，但有人提出，背侧流可能通过在腹侧流对象处理之前快速激活顶叶注意机制来促进对象识别。
为了研究背侧视觉流对对象识别的相对贡献，一组大学生被分为运动一致性好的和差的组，并在经典上被认为依赖于腹侧流处理的任务上进行评估。参与者被要求在两个任务中识别简单的线条图，一个任务中对象以 50 毫秒的速度突然出现，然后是一个白色噪声掩蔽，另一个任务中对比度在线性上升和下降 325 毫秒后替换为掩蔽。
尽管两组仅在运动一致性表现上有所不同（一种背侧流测量），但运动一致性好的组在突然出现的任务中对对象识别的对比度敏感性更高，但在逐渐出现的任务中则不然。
我们提出，对象的突然出现激活了由背侧流提供的注意机制，而逐渐出现的任务则由于瞬态减少而没有很好地激活背侧注意机制。结果表明，快速的背侧流激活可能有助于腹侧流对象处理。
