title: Neural correlates of heat-evoked pain memory in humans.
abstract: The neural processes underlying pain memory are not well understood. To explore these processes, contact heat-evoked potentials (CHEPs) were recorded in humans with electroencephalography (EEG) technique during a delayed matching-to-sample task, a working memory task involving presentations of two successive painful heat stimuli (S-1 and S-2) with different intensities separated by a 2-s interval (the memorization period). At the end of the task, the subject was required to discriminate the stimuli by indicating which (S-1 or S-2) induced more pain. A control task was used, in which no active discrimination was required between stimuli. All event-related potential (ERP) analysis was aligned to the onset of S-1. EEG activity exhibited two successive CHEPs: an N2-P2 complex (∼400 ms after onset of S-1) and an ultralate component (ULC, ∼900 ms). The amplitude of the N2-P2 at vertex, but not the ULC, was significantly correlated with stimulus intensity in these two tasks, suggesting that the N2-P2 represents neural coding of pain intensity. A late negative component (LNC) in the frontal recording region was observed only in the memory task during a 500-ms period before onset of S-2. LNC amplitude differed between stimulus intensities and exhibited significant correlations with the N2-P2 complex. These indicate that the frontal LNC is involved in maintenance of intensity of pain in working memory. Furthermore, alpha-band oscillations observed in parietal recording regions during the late delay displayed significant power differences between tasks. This study provides in the temporal domain previously unidentified neural evidence showing the neural processes involved in working memory of painful stimuli.
authors.affiliation: Key Laboratory of Brain Functional Genomics, MOE and STCSM, Institute of Cognitive Neuroscience, East China Normal University, Shanghai, People's Republic of China; NYU-ECNU Institute of Brain and Cognitive Science at NYU Shanghai and Collaborative Innovation Center for Brain Science, Shanghai, People's Republic of China; xwdong@nbic.ecnu.edu.cn.
authors.forename: Liping
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Brain Functional Genomics, MOE and STCSM, Institute of Cognitive Neuroscience, East China Normal University, Shanghai, People's Republic of China;
authors.forename: Peng
authors.initials: P
authors.lastname: Gui
authors.affiliation: Key Laboratory of Brain Functional Genomics, MOE and STCSM, Institute of Cognitive Neuroscience, East China Normal University, Shanghai, People's Republic of China;
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.affiliation: Key Laboratory of Brain Functional Genomics, MOE and STCSM, Institute of Cognitive Neuroscience, East China Normal University, Shanghai, People's Republic of China; NYU-ECNU Institute of Brain and Cognitive Science at NYU Shanghai and Collaborative Innovation Center for Brain Science, Shanghai, People's Republic of China;
authors.forename: Yixuan
authors.initials: Y
authors.lastname: Ku
authors.affiliation: MIND Research Institute, Irvine, California; and.
authors.forename: Mark
authors.initials: M
authors.lastname: Bodner
authors.affiliation: Department of Psychology, Colorado State University, Fort Collins, Colorado.
authors.forename: Gaojie
authors.initials: G
authors.lastname: Fan
authors.affiliation: NYU-ECNU Institute of Brain and Cognitive Science at NYU Shanghai and Collaborative Innovation Center for Brain Science, Shanghai, People's Republic of China; Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland; Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland;
authors.forename: Yong-Di
authors.initials: YD
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Brain Functional Genomics, MOE and STCSM, Institute of Cognitive Neuroscience, East China Normal University, Shanghai, People's Republic of China; NYU-ECNU Institute of Brain and Cognitive Science at NYU Shanghai and Collaborative Innovation Center for Brain Science, Shanghai, People's Republic of China;
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Dong
mesh_terms: D000328:Adult; D000513:Alpha Rhythm; D004192:Discrimination, Psychological; D005071:Evoked Potentials; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008568:Memory; D058748:Pain Perception; D017288:Pain Threshold; D011930:Reaction Time
keywords: EEG; contact heat-evoked potentials; frontal region; pain; working memory