Barcelo Francisco, Escera Carles, Corral Maria J, Periáñez Jose A
Ed. Beatriu de Pinos, University of Illes Balears, Palma de Mallorca, Spain.
J Cogn Neurosci. 2006 Oct;18(10):1734-48. doi: 10.1162/jocn.2006.18.10.1734.
The abrupt onset of a novel event captures attention away from, and disrupts, ongoing task performance. Less obvious is that intentional task switching compares with novelty-induced behavioral distraction. Here we explore the hypothesis that intentional task switching and attentional capture by a novel distracter both activate a common neural network involved in processing contextual novelty [Barcelo, F., Periáñez, J. A., & Knight, R. T. Think differently: A brain orienting response to task novelty. NeuroReport, 13, 1887-1892, 2002.]. Event-related potentials were recorded in two task-cueing paradigms while 16 subjects sorted cards following either two (color or shape; two-task condition) or three (color, shape, or number; three-task condition) rules of action. Each card was preceded by a familiar tone cueing the subject either to switch or to repeat the previous rule. Novel sound distracters were interspersed in one of two blocks of trials in each condition. Both novel sounds and task-switch cues impaired responses to the following visual target. Novel sounds elicited novelty P3 potentials with their usual peak latency and frontal-central scalp distribution. Familiar tonal switch cues in the three- and two-task conditions elicited brain potentials with a similar latency and morphology as the novelty P3, but with relatively smaller amplitudes over frontal scalp regions. Covariance and principal component analyses revealed a sustained frontal negative potential that was distorting concurrent novelty P3 activity to the tonal switch cues. When this frontal negativity was statistically removed, P3 potentials to novel sounds and task-switch cues showed similar scalp topographies. The degree of activation in the novelty P3 network seemed to be a function of the information (entropy) conveyed by the eliciting stimulus for response selection, over and above its relative novelty, probability of occurrence, task relevance, or feedback value. We conclude that novelty P3 reflects transient activation in a neural network involved in updating task set information for goal-directed action selection and might thus constitute one key element in a central bottleneck for attentional control.
新事件的突然发生会将注意力从正在进行的任务中吸引开，并干扰任务的执行。不太明显的是，有意的任务切换与新奇事物引起的行为分心之间的比较。在这里，我们探讨这样一个假设，即有意的任务切换和由新干扰物引起的注意力捕捉都会激活一个共同的神经网络，该网络参与处理情境新奇性[巴塞罗，F.，佩里亚涅斯，J. A.，& 奈特，R. T. 以不同方式思考：对任务新奇性的大脑定向反应。《神经报告》，13，1887 - 1892，2002年]。在两种任务提示范式中记录了事件相关电位，同时16名受试者按照两种（颜色或形状；双任务条件）或三种（颜色、形状或数字；三任务条件）行动规则对卡片进行分类。每张卡片之前都有一个熟悉的音调，提示受试者切换或重复先前的规则。在每种条件下的两个试验块之一中穿插了新的声音干扰物。新声音和任务切换提示都会损害对随后视觉目标的反应。新声音以其通常的峰值潜伏期和额中央头皮分布引发新奇性P3电位。在三任务和双任务条件下，熟悉的音调切换提示引发的脑电位潜伏期和形态与新奇性P3相似，但在额头皮区域的振幅相对较小。协方差和主成分分析揭示了一个持续的额部负电位，它正在扭曲与音调切换提示同时出现的新奇性P3活动。当从统计学上消除这种额部负电位时，对新声音和任务切换提示的P3电位显示出相似的头皮地形图。新奇性P3网络中的激活程度似乎是由引发刺激为反应选择所传达的信息（熵）的函数，而不仅仅取决于其相对新奇性、发生概率、任务相关性或反馈价值。我们得出结论，新奇性P3反映了一个神经网络中的瞬时激活，该网络参与更新用于目标导向行动选择的任务集信息，因此可能构成注意力控制中央瓶颈中的一个关键要素。
