Human brain activation under controlled thermal stimulation and habituation to noxious heat: an fMRI study. |
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| Authors: | L R Becerra H C Breiter M Stojanovic S Fishman A Edwards A R Comite R G Gonzalez D Borsook |
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| Affiliation: | MGH-Nuclear Magnetic Resonance Center, and Department of Neuroradiology, Massachusetts General Hospital and Harvard Medical School, Boston, USA. |
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| Abstract: | 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. |
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