Brain source imaging of the alpha rhythm in PTSD patients using the MEG technique
In anxiety disorders, such as PTSD, brain imaging has demonstrated local modifications of functional activities using various techniques. In the present study the direct neuronal activities were measured in delta, theta and beta frequencies, using Magnetoencephalagraphy (MEG) which provides very fast temporal response. The technique is neither invasive nor stressful for the patients. Nineteen female volunteers with DSM-IV PTSD were included in the study. The protocol was a script-driven imagery provocation test, achieved with the patients sitting in the MEG apparatus. The scenarios, specific for ach patient, were composed of 4 active conditions: neutral image (N) traumatic memory (T), traumatic memory suppression (TS) and positive image (P) corresponding to 3 minutes where the patient had to imagine the corresponding sequence with eyes closed Measures of heat rate and subjective disturbance (SUD) were measured during the recoding. The MEG data were analysed in the source domain using a spatial filtering approach. Measurement of electrophysiological waves of various rhythms: delta: 1-4 Hetz (Hz), theta: 4.8-5.8 Hz, alpha: 8-12 Hz and beta: 12-25 Hz was obtained. Anatomical information was from MRI imaging. Signal of activation during trauma recall (T-N) were limited to the delta and theta waves and mainly found in the left hemisphere (visual, orbitofrontal and dorsolateral prefrontal and temporal gyrus (BA 8-9-10-11, 18-19, 22, 28) and in the right supra marginal gyrus (Wernicke BA 40). Signal of inhibition during trauma recall (T-N) were found mainly in the left hemisphere, in the delta, alpha and beta waves (visual, orbitofrontal, dorsolateral prefrontal and temporal gyrus (BA 8-9-10-11, 18-18, 22, 28), cingular cortex (BA 23-24, 31, 32), insula (BA 13) and Broca visual cortex (BA 18-19, 43-44). In conclusion trauma recall mainly induces a hypoactivation in the ventromedial prefrontal cortex and in the cingular cortices, structures linked to the experience and regulation of emotions.
Original Work Citation
Haour, F. (2009, June). Brain source imaging of the alpha rhythm in PTSD patients using the MEG technique. In K. Zaal (Chair), Research). Symposium conducted at the 10th EMDR Europe Association Conference, Amsterdam, The Netherlands
“Brain source imaging of the alpha rhythm in PTSD patients using the MEG technique,” Francine Shapiro Library, accessed June 24, 2021, https://emdria.omeka.net/items/show/19292.