Target selection in area V4 during a multidimensional visual search task
Target selection in area V4 during a multidimensional visual search task
复制标题
DOI：
10.1523/jneurosci.0569-04.2004
复制
发表时间：
2004-07-14
影响因子：
5.3
通讯作者：
Komatsu, H
中科院分区：
文献类型：
--
作者：
Ogawa, T;Komatsu, H
自然场景通常包含多个对象，这些对象在不同的刺激维度上是唯一的，因此与周围对象具有特征对比度的对象会引起注意并突出。此外，如果我们之前了解目标对象与周围对象不同的维度，我们将关注该维度并更容易检测到目标。我们的目的是通过记录V4区的神经元活动来阐明这种类型注意的神经机制，并研究对象之间的视觉信号编码特征对比度如何被特定于特定维度的注意所调制。为了实现这一点，我们训练猴子做一个多维视觉搜索任务，其中两个单一的刺激，独特的颜色或形状的维度，提出了与其他四个相同的刺激。猴子必须在指示维度中搜索唯一的单一刺激，而搜索维度在形状和颜色之间切换。我们发现，单个V4神经元携带的视觉信号编码功能对比度的形状或颜色，这个信号的调制取决于搜索维度。人口反应的目标单例刺激显着高于其他人，无论搜索维度。然而，在大多数V4神经元中，只有当一个特定的单一刺激是目标时，才会发生显着的反应增加。这些研究结果表明，自下而上的信号编码的特征刺激之间的对比度和自上而下的信号编码的搜索维度之间的相互作用发生在V4和促进自适应选择的目标在一个复杂的视觉环境。
Natural scenes typically contain multiple objects that are unique in different stimulus dimensions so that an object with feature contrast to surrounding objects draws attention and pops out. Furthermore, if we have previous knowledge about the dimension in which a target object differs from the surrounding objects, we will attend to that dimension and more easily detect the target. Our aims here were to elucidate neural mechanisms underlying this type of attention by recording neuronal activities from area V4 and to investigate how visual signals encoding feature contrast between objects are modulated by attention specific to a particular dimension. To accomplish this, we trained monkeys to do a multidimensional visual search task in which two singleton stimuli, unique in the color or shape dimension, were presented with four other identical stimuli. The monkeys had to search for the singleton stimulus that was unique in the instructed dimension while the search dimension was switched between shape and color. We found that individual V4 neurons carry visual signals encoding feature contrast in either shape or color, and this signal is modulated depending on the search dimension. Population responses to the target singleton stimulus were significantly higher than to others, regardless of the search dimension. In most V4 neurons, however, significant response increases occurred only when one particular singleton stimulus was the target. These findings suggest that interaction between bottom-up signals encoding feature contrast between stimuli and top-down signals encoding search dimension occurs in V4 and facilitates adaptive selection of targets in a complex visual environment.