Noxious somatosensory stimulation affects the default-mode of brain function: evidence from functional MRI
Mantini, Dante × Caulo, Massimo Ferretti, Antonio Romani, Gian Luca Tartaro, Armando #
Radiological Society of North America
Radiology vol:253 issue:3 pages:797-804
Purpose: A number of neuroimaging studies have reported the deactivation during pain of the default-mode network (DMN), associated with ongoing internal brain processes. As the DMN has been found to be influenced by sensory and cognitive tasks, we investigated whether the DMN spatial properties can be directly affected by pain, comparing painful and non-painful conditions.
Methods and material: We carried out a functional magnetic resonance imaging (fMRI) study, approved by our local Institutional Ethics Committee, on 10 healthy male subjects (18-45 years) who signed a written informed consent. They underwent 2 experimental sessions of median nerve electrical stimulation at painful and non-painful levels. We used independent component analysis (ICA) on the fMRI data to obtain the DMN spatio-temporal pattern. Group-level DMN connectivity maps were obtained for painful and non-painful conditions (p<0.001 corrected with false discovery rate, FDR). A contrast between the connectivity maps in the two conditions was computed as well (p <0.05 FDR-corrected).
Results: Our results show that the DMN, while maintaining its typical temporal properties, is subject to modifications in its connectivity pattern during painful stimulation, recruiting brain areas associated with pain processing. Increased connectivity in painful condition is mainly found in the left prefrontal cortex and in the posterior cingulate/precuneus, and decreased connectivity is found in the lateral parietal cortex.
Conclusion: Our findings are in line with the impairments of the DMN reported in chronic pain patients. They support the hypothesis that the alteration of the DMN connectivity pattern during acute pain, localized within specific brain areas, might induce, if repeated across time, permanent changes able to disrupt the DMN functional architecture.