Human brain activation under controlled thermal stimulation and habituation to noxious heat: an fMRI study.
Brain activity was studied with functional magnetic resonance imaging (fMRI) following thermal stimulation. Two groups (n = 6/group) of human male volunteers were given up to four noxious (46 degrees C) and four non-noxious (41 degrees C) stimuli. In the 46 degrees C experiment, positive signal changes were found in the frontal gyri, anterior and posterior cingulate gyrus, thalamus, motor cortex, somatosensory cortex (SI and SII), supplementary motor area, insula, and cerebellum. Low-level negative signal changes appeared in the amygdala and hypothalamus. All regions activated by 46 degrees C were also activated by 41 degrees C. However, except for SI and thalamus, significantly more activation was observed for the 46 degrees C stimulus. A significant attenuation of the signal change was observed by the third stimulus for the 46 degrees C, but not for 41 degrees C experiment. Similar findings were replicated in the second group. These fMRI findings specify differences between somatosensory and pain sensation and suggest a number of rich avenues for future research.
Becerra
L R
LR
MGH-Nuclear Magnetic Resonance Center, and Department of Neuroradiology, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
Breiter
H C
HC
Stojanovic
M
M
Fishman
S
S
Edwards
A
A
Comite
A R
AR
Gonzalez
R G
RG
Borsook
D
D
D000328:Adult; D000679:Amygdala / Q000502:physiology; D000704:Analysis of Variance; D001921:Brain / Q000502:physiology*; D002531:Cerebellum / Q000502:physiology; D002540:Cerebral Cortex / Q000502:physiology; D005625:Frontal Lobe / Q000502:physiology; D006179:Gyrus Cinguli / Q000502:physiology; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D007031:Hypothalamus / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D010146:Pain / Q000503:physiopathology; D010147:Pain Measurement; D010296:Parietal Lobe / Q000502:physiology; D010812:Physical Stimulation; D015203:Reproducibility of Results; D012677:Sensation / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology; D013702:Temporal Lobe / Q000502:physiology; D013788:Thalamus / Q000502:physiology