Segregable loci of orbitofrontal trigger regions for emotion release following happy and sad facial expression stimulation in ER-fMRI – fMRI-online psychophysiology and BOLD signal time series extraction in depersonalization patients and normal volunteers

9 DPD patients were compared with 12 normal control volunteers in their cerebral activation patterns, levels of sympathetic outflow, and behavioral measures. Emotional facial expressions of happiness and sadness in three intensity levels (0%–50%–100%) were presented in an implicit ER-fMRI experimental paradigm combined with simultaneous online-recording of skin conductance levels. To obtain “pure“ emotion-induced cerebral activation, 100%–50% subtraction contrast maps were generated, thereby removing face-specific activation. Using 50%–100% emotion specific SCL aggregates, correlation overlap images were produced at P <0,0001 with less than 1 error voxel over the entire brain. Whilst the behavioral results revealed significant group-specific differences in most of the clinical taxons administered to both groups (STAI, DES; CDS, BDI, SOMS, TAS-20), SCL values were found to display sufficient between-condition stability and discrimination for each emotion. Using ANCOVA, significant between-group main effects were present for all six investigated emotion categories. In happiness, left marginal gyrus rectus (BA 11; x=–31, y=41, z=–18) was activated in normals, and left posteromedial gyrus rectus (BA 12; x=–10, y=38, z=–7) in DPD patients. For sadness, right medial orbital gyrus (BA 10; x=7, y=52, z=–2) was engaged in controls, and right anterior medial gyrus rectus (BA 11; x=7, y=56, z=4) was involved in DPD patients. BOLD signal time course extraction for all regions demonstrated to be in emotion- specific functional connectivity with ANS revealed that depersonalization patients have a majority of first deflections of the BOLD response at 2 s post-stimulus, irrespective of the expression intensity of the emotional stimulus. These results imply that in depersonalization a faster recognition component for emotion signals is effective, whilst components for emotion experience suppression await further elucidation.

Key words

BOLD signal time series - cerebral cortex - depersonalization disorder - fMRI - human emotion - joy - psychophysiology - sadness