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Intrinsic functional connectivity of the periaqueductal gray, a resting fMRI study

Department of Psychiatry, Massachusetts General Hospital (MGH), Harvard Medical School, Charlestown, MA 02129, USA.
Behavioural brain research (Impact Factor: 3.39). 03/2010; 211(2):215-9. DOI: 10.1016/j.bbr.2010.03.042
Source: PubMed

ABSTRACT The periaqueductal gray (PAG) is known to play a crucial role in pain modulation and has shown a strong interaction with anterior cingulate cortex in previous functional imaging studies. We investigated the intrinsic functional connectivity of PAG using resting fMRI data from 100 subjects. The results showed that PAG is functionally connected to ACC (rostral and pregenual ACC) and also rostral ventromedial medulla (RVM), forming a core ACC-PAG-RVM network for pain modulation even no pain stimulus is applied. The comparison between genders showed that for the contrast of female minus male, significant difference was observed at mid-cingulate cortex; for the contrast of male minus female, significant differences were observed at left medial orbital prefrontal cortex, and uncus; right insula/operculum and prefrontal cortex. We believe eluciation of this intrinsic PAG network during the resting state will enhance our physiological and pathological understandings of the development and maintenance of chronic pain states.

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    • "The opposite contrast revealed significant activation in the bilateral ventromedial dorsolateral prefrontal cortex (vmPFC), precuneus/posterior cingulate cortex, hippocampus, and cerebellar cortex (Fig. 3). These main effects are consistent with previous findings on the patterns of pain-elicited neural activation and deactivation (Kong et al., 2010a). "
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    • "The opposite contrast revealed significant activation in the bilateral ventromedial dorsolateral prefrontal cortex (vmPFC), precuneus/posterior cingulate cortex, hippocampus, and cerebellar cortex (Fig. 3). These main effects are consistent with previous findings on the patterns of pain-elicited neural activation and deactivation (Kong et al., 2010a). "
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    • "Direct comparison between the pain and nonpainful pressure conditions shows that painful pressure evokes significantly greater fMRI signal changes in bilateral thalamus, caudate, putamen , periaqueductal gray (PAG), rostral ventromedial medulla (RVM), and cerebellum (Fig. 1b and Table 2); while non-painful pressure evokes more fMRI signal changes in supplementary motor area, posterior cingulate, and precuneus/cuneus (Table 2). The PAG and RVM are part of the descending pain modulatory network (Kong et al., 2010b). However, it is possible that a brain region being identified when comparing nonpainful pressure N pain could indeed show a less negative change during nonpainful than painful pressure. "
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