Distraction affects frontal alpha rhythms related to expectancy of pain: an EEG study.
Previous electroencephalographic (EEG) evidence has shown event-related desynchronization (ERD) of alpha rhythms before predictable painful stimuli, as a possible neural concomitant of attentional preparatory processes (Babiloni, C., Brancucci, A., Babiloni, F., Capotosto, P., Carducci, F., Cincotti, F., Arendt-Nielsen, L., Chen, A.C., Rossini, P.M., 2003. Anticipatory cortical responses during the expectancy of a predictable painful stimulation. A high-resolution electroencephalography study. Eur. J. Neurosci. 18 (6) 1692-700). This study tested the hypothesis that alpha ERD before predictable painful stimuli is reduced as an effect of distraction. A visual warning stimulus preceded a laser painful stimulation, which was strictly followed by visual imperative stimuli. In the Pain (control) condition, no task was required after the imperative stimuli. In the Pain + Movement condition, subjects had to perform a movement of the right index finger. In the Pain + Cognition condition, they had to mentally perform an arithmetical task. EEG data were recorded in 10 subjects from 30 electrodes. Artifact-free recordings were spatially enhanced by surface Laplacian transformation. Alpha ERD was computed at three alpha sub-bands according to subjects' individual alpha frequency peak (i.e., about 6-8 Hz, 8-10 Hz, 10-12 Hz). Compared to the control condition, the subjects reported a significantly lower stimulus intensity perception and unpleasantness in the Pain + Movement and Pain + Cognition conditions. In addition, there was a cancellation of the alpha 3 ERD (i.e., about 10-12 Hz) in Pain + Cognition condition and even a generation of a statistically significant alpha 3 ERS in Pain + Movement condition. These effects were maximum over fronto-central midline. These results suggest that distraction during the expectancy of pain is related to a reduced neural desynchronization of fronto-central midline alpha rhythms (i.e., reduced cortical activation) towards an overt hyper-synchronization (cortical idling).
Del Percio
Claudio
C
Dipartimento di Fisiologia Umana e Farmacologia, Università La Sapienza, Rome, Italy. claudio.delpercio@uniroma1.it
Le Pera
Domenica
D
Arendt-Nielsen
Lars
L
Babiloni
Claudio
C
Brancucci
Alfredo
A
Chen
Andrew C N
AC
De Armas
Liala
L
Miliucci
Roberto
R
Restuccia
Domenico
D
Valeriani
Massimiliano
M
Rossini
Paolo Maria
PM
D000328:Adult; D000513:Alpha Rhythm; D001288:Attention / Q000502:physiology*; D001364:Awareness / Q000502:physiology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D003344:Cortical Synchronization; D004569:Electroencephalography; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009044:Motor Cortex / Q000503:physiopathology; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology; D011340:Problem Solving / Q000502:physiology*; D012718:Set, Psychology; D012815:Signal Processing, Computer-Assisted; D013003:Somatosensory Cortex / Q000503:physiopathology