Spatial summation of pain processing in the human brain as assessed by cerebral event related potentials.
To understand spatial summation of pain processing in the brain, we investigated the cerebral evoked responses to non-painful and painful contact heat stimulation (70 degrees C/s fast onset; intensity 2,4,6, corresponding to the individual's non-, slight and moderate pain) comparing one (1s) vs. two spots (2s) in 11 subjects while electroencephalographic signals were recorded. Significant spatial summation effects were shown only for the pain levels. For moderate pain, global field power examination isolated two peak activations for the vertex (Cz) N550 and P750 components. The single dipole modelling identified as likely the supplementary motor area, SMA area-6 source for N550, and posterior cingulate area-23 for P750. These source components showed a significantly faster (41.2 ms) latency and a shift in location from dorsal to ventral SMA of N550 toward cingulate area-31 between the 1s and 2s conditions. The temporal and spatial shift during spatial summation may reflect speeding up of the limbic affective reaction and prefrontal cognitive preparation in impending aversion and is deemed essential for integration of bodily sensations, such as pain.
Human Brain Mapping and Cortical Imaging Laboratory, The International Doctoral School in Biomedical Sciences and Engineering, Centre for Sensory Motor Interaction, Aalborg University, Fredrik Bajes Vej 7D3, Aalborg 9220, Denmark. ac@smi.auc.dk
Andrew C N
AC
Chen
David M
DM
Niddam
Helen J
HJ
Crawford
Robert
R
Oostenveld
Lars
L
Arendt-Nielsen
D000328:Adult; D000344:Afferent Pathways / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D014644:Genetic Variation / Q000502:physiology; D006179:Gyrus Cinguli / Q000502:physiology; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology*; D009619:Nociceptors / Q000502:physiology*; D010146:Pain / Q000503:physiopathology*; D010812:Physical Stimulation / Q000009:adverse effects; D011930:Reaction Time / Q000502:physiology*