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. 2018 Jan 15;141(2):357–364. doi: 10.1093/brain/awx337

Figure 4.

Figure 4

vlPAG functional connectivity predicts heat hyperalgesia. (A) A schematic of the analysis workflow used to test the relationship between the functional connectivity (F.C.) strength of the vlPAG-rACC (acquired in Scan 2) and the patients’ behavioural (B) and brain (C) responses to evoked tonic heat applied to their feet (acquired in Scan 3). (B) A linear correlation between resting vlPAG-rACC functional connectivity strength (from Scan 2) and the intensity of the pain reported during evoked tonic heat applied to the participants’ feet (from Scan 3; NP+: blue; non-NP: grey). (C) Tonic-heat induced hyper-perfusion (CBF; acquired in Scan 3) as a function of resting vlPAG-rACC functional connectivity (acquired during Scan 2). Regions within which the correlation between tonic heat induced changes in CBF and vlPAG-rACC connectivity strength were greater in NP+ versus non-NP patients are shown in red (n = 26, mixed effects, z > 3.1, P < 0.05 cluster corrected). The axial slices show the extent of activation across the whole brain. Radiological convention is used. FMRI = functional MRI.