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Publication
Alterations in brain activity after rTMS-treatment in a passive viewingfMRI experiment
Book Contribution - Book Chapter Conference Contribution
Introduction:
Studies have shown a different activation pattern in the limbic
and prefrontal regions between normal subjects and depressed patients
who are looking at positively or negatively valenced pictures [1]. Repetitive
transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal
cortex (DLPFC) has been introduced as a therapeutic tool for depression.
Although a reduction of depressive symptoms in patients after rTMS-treatment
has been reported [2], the interaction effects with the brain still remain
unclear. We have investigated the effect of one rTMS-session on brain activation
with fMRI with a passive viewing protocol.
Methods:
19 non-depressed female subjects (25±5 years) who conformed
the current guidelines for rTMS and MRI research where included. 10
underwent an active rTMS-session (10Hz; 40 trains of 3.9s; intertrain
interval=26.1s) while 9 underwent a sham session. Just before and 1h after
the rTMS-session, we performed an fMRI experiment consisting of 20s duration
blocks of pictures of happy, pitiful and scrambled baby faces as positive,
negative and neutral blocks respectively. All volunteers were asked to
empathize with the facial emotions as much as possible. We measured 127
EPI images (TR/TE=3000/35ms; 18 slices; matrix size=64x64) with a 1.5T
Philips MRI scanner.
Results:
In SPM5, we calculated for each individual and each fMRI-session
the percentage signal change maps for the contrasts "positive versus neutral"
and "negative versus neutral". On these maps we performed an ANOVA analysis
"before versus after x active versus sham". For the first contrast, interactions
(rTMS-treatment effects) were found at the temporal gyrus (BA21/22)
bilateral, the right cingulate gyrus (BA24/31), the left frontal gyrus (BA10/11)
and the right frontal gyrus (BA6/9/10). For the second contrast, interactions
were found at the left temporal gyrus (hippocampus) the cingulate gyrus
(BA24/32) bilateral and the left frontal gyrus (BA9). The interaction clusters
were identified on an F-statistic image with p(unc)10 pixels.
Conclusions:
By measuring the second fMRI 1 hour after the rTMS-session,
we looked at the impact of one rTMS-session on mood processing. Although
studies observed no subjective mood changes in healthy volunteers [3], we
found interactions at the cingulate and frontal gyri. Metabolic changes and
changes in brain activity in these regions are shown to correlate with an
antidepressant treatment response [4,5].
References:
[1] Lee B.T.(2007): Progress in Neuro-Psychopharmacology & Biological
Psychiatry;31:1487-1492
[2] Schutter DJ.(2008): Psychological medicine;30:1-11
[3] Baeken C.(2008): Clinical Neurophysiology;119:568-575
[4] Yu C.H.(2007): American Journal of Psychiatry;164:599-607
[5] Luborzewski A.(2007): Journal of Psychiatric Research;41:606-615
Studies have shown a different activation pattern in the limbic
and prefrontal regions between normal subjects and depressed patients
who are looking at positively or negatively valenced pictures [1]. Repetitive
transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal
cortex (DLPFC) has been introduced as a therapeutic tool for depression.
Although a reduction of depressive symptoms in patients after rTMS-treatment
has been reported [2], the interaction effects with the brain still remain
unclear. We have investigated the effect of one rTMS-session on brain activation
with fMRI with a passive viewing protocol.
Methods:
19 non-depressed female subjects (25±5 years) who conformed
the current guidelines for rTMS and MRI research where included. 10
underwent an active rTMS-session (10Hz; 40 trains of 3.9s; intertrain
interval=26.1s) while 9 underwent a sham session. Just before and 1h after
the rTMS-session, we performed an fMRI experiment consisting of 20s duration
blocks of pictures of happy, pitiful and scrambled baby faces as positive,
negative and neutral blocks respectively. All volunteers were asked to
empathize with the facial emotions as much as possible. We measured 127
EPI images (TR/TE=3000/35ms; 18 slices; matrix size=64x64) with a 1.5T
Philips MRI scanner.
Results:
In SPM5, we calculated for each individual and each fMRI-session
the percentage signal change maps for the contrasts "positive versus neutral"
and "negative versus neutral". On these maps we performed an ANOVA analysis
"before versus after x active versus sham". For the first contrast, interactions
(rTMS-treatment effects) were found at the temporal gyrus (BA21/22)
bilateral, the right cingulate gyrus (BA24/31), the left frontal gyrus (BA10/11)
and the right frontal gyrus (BA6/9/10). For the second contrast, interactions
were found at the left temporal gyrus (hippocampus) the cingulate gyrus
(BA24/32) bilateral and the left frontal gyrus (BA9). The interaction clusters
were identified on an F-statistic image with p(unc)10 pixels.
Conclusions:
By measuring the second fMRI 1 hour after the rTMS-session,
we looked at the impact of one rTMS-session on mood processing. Although
studies observed no subjective mood changes in healthy volunteers [3], we
found interactions at the cingulate and frontal gyri. Metabolic changes and
changes in brain activity in these regions are shown to correlate with an
antidepressant treatment response [4,5].
References:
[1] Lee B.T.(2007): Progress in Neuro-Psychopharmacology & Biological
Psychiatry;31:1487-1492
[2] Schutter DJ.(2008): Psychological medicine;30:1-11
[3] Baeken C.(2008): Clinical Neurophysiology;119:568-575
[4] Yu C.H.(2007): American Journal of Psychiatry;164:599-607
[5] Luborzewski A.(2007): Journal of Psychiatric Research;41:606-615
Book: Proceedings ESMRMB 2008
Pages: 335-335
Number of pages: 1
Publication year:2008
Keywords:fMRI, TMS