Bichot Narcisse P, Rossi Andrew F, Desimone Robert
Laboratory of Neuropsychology, National Institute of Mental Health (NIMH), National Institutes of Health, Bethesda, MD 20892, USA.
Science. 2005 Apr 22;308(5721):529-34. doi: 10.1126/science.1109676.
To find a target object in a crowded scene, a face in a crowd for example, the visual system might turn the neural representation of each object on and off in a serial fashion, testing each representation against a template of the target item. Alternatively, it might allow the processing of all objects in parallel but bias activity in favor of those neurons that represent critical features of the target, until the target emerges from the background. To test these possibilities, we recorded neurons in area V4 of monkeys freely scanning a complex array to find a target defined by color, shape, or both. Throughout the period of searching, neurons gave enhanced responses and synchronized their activity in the gamma range whenever a preferred stimulus in their receptive field matched a feature of the target, as predicted by parallel models. Neurons also gave enhanced responses to candidate targets that were selected for saccades, or foveation, reflecting a serial component of visual search. Thus, serial and parallel mechanisms of response enhancement and neural synchrony work together to identify objects in a scene. To find a target object in a crowded scene, a face in a crowd for example, the visual system might turn the neural representation of each object on and off in a serial fashion, testing each representation against a template of the target item. Alternatively, it might allow the processing of all objects in parallel but bias activity in favor of those neurons that represent critical features of the target, until the target emerges from the background. To test these possibilities, we recorded neurons in area V4 of monkeys freely scanning a complex array to find a target defined by color, shape, or both. Throughout the period of searching, neurons gave enhanced responses and synchronized their activity in the gamma range whenever a preferred stimulus in their receptive field matched a feature of the target, as predicted by parallel models. Neurons also gave enhanced responses to candidate targets that were selected for saccades, or foveation, reflecting a serial component of visual search. Thus, serial and parallel mechanisms of response enhancement and neural synchrony work together to identify objects in a scene.
为了在拥挤场景中找到目标物体，例如人群中的一张脸，视觉系统可能会以串行方式打开和关闭每个物体的神经表征，将每个表征与目标物体的模板进行比对。或者，它可能会并行处理所有物体，但使活动偏向于那些代表目标关键特征的神经元，直到目标从背景中显现出来。为了测试这些可能性，我们记录了猴子V4区域的神经元活动，这些猴子自由扫视一个复杂阵列以找到由颜色、形状或两者定义的目标。在整个搜索过程中，正如并行模型所预测的那样，每当其感受野中的偏好刺激与目标的一个特征匹配时，神经元就会给出增强反应，并在伽马范围内同步其活动。神经元对被选为扫视或注视的候选目标也会给出增强反应，这反映了视觉搜索的串行成分。因此，反应增强和神经同步的串行和并行机制共同作用以识别场景中的物体。为了在拥挤场景中找到目标物体，例如人群中的一张脸，视觉系统可能会以串行方式打开和关闭每个物体的神经表征，将每个表征与目标物体的模板进行比对。或者，它可能会并行处理所有物体，但使活动偏向于那些代表目标关键特征的神经元，直到目标从背景中显现出来。为了测试这些可能性，我们记录了猴子V4区域的神经元活动，这些猴子自由扫视一个复杂阵列以找到由颜色、形状或两者定义的目标。在整个搜索过程中，正如并行模型所预测的那样，每当其感受野中的偏好刺激与目标的一个特征匹配时，神经元就会给出增强反应，并在伽马范围内同步其活动。神经元对被选为扫视或注视的候选目标也会给出增强反应，这反映了视觉搜索的串行成分。因此，反应增强和神经同步的串行和并行机制共同作用以识别场景中的物体。
