C. Babiloni et al., Mapping of early and late human somatosensory evoked brain potentials to phasic galvanic painful stimulation, HUM BRAIN M, 12(3), 2001, pp. 168-179
In the present study, we modeled the spatiotemporal evolution of human soma
tosensory evoked cortical potentials (SEPs) to brief median-nerve galvanic
painful stimulation. SEPs were recorded (-50 to +250 ms) from 12 healthy su
bjects following nonpainful (reference), slight painful, and moderate painf
ul stimulations (subjective scale). Laplacian transformation of scalp SEPs
reduced head volume conduction effects and annulled electric reference infl
uence. Typical SEP components to the galvanic nonpainful stimulation were c
ontralateral frontal P20-N30-N60-N120-P170, central P22-P40, and parietal N
20-P30-P60-P120 (N = negativity P = positivity number = latency in ms). The
se components were observed also with the painful stimulations, the N60, N1
20, P170 having a longer latency with the painful than nonpainful stimulati
ons. Additional SEP components elicited by the painful stimulations were pa
rietomedian P80 as well as central N125, P170 (cP170), and P200. These addi
tional SEP components included the typical vertex negative-positive complex
following transient painful stimulations. Latency of the SEP components ex
clusively elicited by painful stimulation is highly compatible with the inv
olvement of A delta myelinated fibers/spinothalamic pathway. The topography
of these components is in line with the response of both nociceptive media
l and lateral systems including bilateral primary sensorimotor and anterior
cingulate cortical areas. The role of attentive, affective, and motor aspe
cts in the modulation of the reported SEP components merits investigation i
n future experiments. Hum. Brain Mapping 12:168-179, 2001. (C) 2001 Wiley-L
iss, Inc.