COGNITIVE NEUROSCIENCE AND NEUROPSYCHOLOGYStimulus intensity affects the latency but not the amplitude of the N2pcBrisson, Benoit; Robitaille, Nicolas; Jolicœur, PierreAuthor Information Research center in Neuropsychology and Cognition, University of Montreal, Montreal, Quebec, Canada Correspondence to Benoit Brisson, Département de Psychologie, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, Québec, Canada H3C 3J7 Tel: +1 514 343 6111 ext. (2631); fax: +1 514 343 5787; e-mail: [email protected] Received 5 July 2007; accepted 22 July 2007 NeuroReport: October 8, 2007 - Volume 18 - Issue 15 - p 1627-1630 doi: 10.1097/WNR.0b013e3282f0b559 Buy Metrics Abstract The N2pc component of the event-related potential (ERP) is an index of visual–spatial attention. It is not clear whether the N2pc reflects pure top-down attentional activity or an interaction of top-down activity with bottom-up sensory activity. Here, we manipulated stimulus intensity of the items composing the target display. Although the amplitude of the P1 component increased monotonically with increasing stimulus intensity, the amplitude of the N2pc did not vary with stimulus intensity. Instead, the onset latency of the N2pc was delayed for weaker stimuli, suggesting that the strength of the selection cue (target color) influenced the moment at which attention was deployed. The results reveal one way in which early sensory ERP amplitude differences are converted into later latency differences. © 2007 Lippincott Williams & Wilkins, Inc.