Task Switching and Novelty Processing Activate a Common Neural Network for Cognitive Control
1221Francisco Barcelo, Carles Escera, Maria J. Corral and Jose A. Periáñez
12 University of Illes Balears, Palma de Mallorca, Spain, University of Barcelona, Spain
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The abrupt onset of a novel event captures attention away from,and disrupts, ongoing task performance. Less obvious is thatintentional task switching compares with novelty-induced behavioraldistraction. Here we explore the hypothesis that intentionaltask switching and attentional capture by a novel distracterboth activate a common neural network involved in processingcontextual novelty [Barcelo, F., Periáñez, J.A., & Knight, R. T. Think differently: A brain orientingresponse to task novelty. NeuroReport, 13, 1887–1892,2002.]. Event-related potentials were recorded in two task-cueingparadigms 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 cardwas preceded by a familiar tone cueing the subject either toswitch or to repeat the previous rule. Novel sound distracterswere interspersed in one of two blocks of trials in each condition.Both novel sounds and task-switch cues impaired responses tothe following visual target. Novel sounds elicited novelty P3potentials with their usual peak latency and frontal–centralscalp 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 relativelysmaller amplitudes over frontal scalp regions. Covariance andprincipal component analyses revealed a sustained frontal negativepotential that was distorting concurrent novelty P3 activityto the tonal switch cues. When this frontal negativity was statisticallyremoved, P3 potentials to novel sounds and task-switch cuesshowed similar scalp topographies. The degree of activationin 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 noveltyP3 reflects transient activation in a neural network involvedin updating task set information for goal-directed action selectionand might thus constitute one key element in a central bottleneckfor attentional control.
Journal of Cognitive Neuroscience. 2006;18:1734-1748