Summary
Objectives: Connectivity analysis was used to investigate the processing of intracutaneous stimuli
and directed interactions within the pain matrix in patients with major depression
(MD) and healthy controls (HCs), by means of frequency selective generalized partial
directed coherence (gPDC).
Methods: Eighteen patientswithMDand 18 HCs underwent stimulations consisting of moderately
painful intracutaneous electrical stimuli to the right and left middle fingers. Connectivity
analysis was based on nine selected EEG electrodes.
Results: Stimulus-induced changes of the gPDC in a pre/post stimulus comparison and changes
in the connectivity pattern in the post-stimulus condition were found. We could identify
network changes correlating to the side stimulated, as well as differences between
HCs and MD patients.
Conclusions: These data support the suggestion that pain processing in response to noxious stimulation
in MD patients is different compared to healthy controls, suggesting aberrant functional
connectivity. Generalized partial directed coherence is shown to be a promising method
to detect changes in connectivity in both within- and between-subject designs.
Keywords
EEG - generalized partial directed coherence - major depression - connectivity analysis