Dante Mantini PhD, Presenter: Nothing to Disclose

Massimo Caulo MD, PhD, Abstract Co-Author: Nothing to Disclose

Gian Luca Romani, Abstract Co-Author: Nothing to Disclose

Armando Tartaro MD, Abstract Co-Author: Nothing to Disclose

Several functional neuroimaging studies have consistently provided evidence for a network of brain areas, including primary and secondary somatosensory cortices, insula, anterior cingulate, and thalamus, that increase their activity in response to noxious stimuli. More recently, another network, the default-mode network (DMN), that is typically associated with ongoing internal brain processes, has been observed to be involved in pain perception, and specifically to deactivate during noxious stimulation. Based on previous studies on the DMN functional organization, we hypothesized that the spatial properties of the DMN might be modulated by pain perception at different stimulation intensity levels.

We carried out a blocked-design fMRI study on 10 healthy subjects, comparing the brain activity during painful and non-painful somatosensory stimulations. For the detection of the DMN activity from the fMRI time-courses, we used a data-driven analysis method based on spatial independent component analysis (sICA). Spatial ICA allows the decomposition of the voxel time-series into a set of independent spatio-temporal patterns, each of them composed of coherent brain areas.

The results provided by sICA evidenced a significant modulation of the DMN areas during pain, with increased functional connectivity in the subgenual cingulate and the left prefrontal cortex, and decreased connectivity in the right parietal cortex. Furthermore, we found larger brain activity for painful than non-painful condition in the secondary somatosensory cortex, the bilateral insula, the anterior and posterior cingulates, and the right dorso-lateral prefrontal cortex. Smaller activity was observed in the intra-parietal sulcus, the human frontal eye field, the middle frontal gyrus, the medial frontal cortex, and the thalamus.

Our study supports the idea that external stimuli might have an impact on the DMN, which is supposed to largely account for the ongoing neuronal activity in the human brain. Our data revealed that the DMN, also maintaining its well-known temporal properties, is subjected to a modification in its connectivity pattern during noxious stimulation, also recruiting brain areas that might be associated with pain perception.

The present study might represent an important step toward the comprehension of acute pain influence on ongoing brain dynamics.

Mantini, D, Caulo, M, Romani, G, Tartaro, A, Influence of Noxious Somatosensory Stimulation on the Human Default-mode Network: An fMRI Study.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6009309.html