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- Gingnell, Malin, 1982-
(författare)
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Ovarian Steroid Hormones, Emotion Processing and Mood
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- It is known that some psychiatric disorders may deteriorate in relation to the menstrual cycle. However, in some conditions, such as premenstrual dysphoric disorder (PMDD), symptomatology is triggered mainly by the variations in ovarian steroid hormones. Although symptoms induced by fluctuations in ovarian steroids often are affective, little is known about how emotion processing in women is influenced by variations, or actual levels, of ovarian steroid hormones.The general aim of this thesis was to evaluate menstrual cycle effects on reactivity in emotion generating and controlling areas in the corticolimbic system to emotional stimulation and anticipation, in healthy controls and women with PMDD. A second aim was to evaluate corticolimbic reactivity during long-term administration of exogenous ovarian steroids.In study I, III and IV effects of the menstrual cycle on emotional reactivity in women with PMDD was studied. In study I, women with PMDD in displayed higher amygdala reactivity than healthy controls to emotional faces, not in the luteal phase as was hypothesised, but in the follicular phase. No difference between menstrual cycle phases was obtained in women with PMDD, while healthy controls had an increased reactivity in the luteal phase. The results of study I was further elaborated in study III, where women with PMDD were observed to have an increased anticipatory reactivity to negative emotional stimuli. However, no differences in amygdala reactivity to emotional stimuli were obtained across the menstrual cycle. Finally, in study IV the hypothesis that amygdala reactivity increase in the luteal phase in women with PMDD is linked to social stimuli rather than generally arousing stimuli was suggested, tested and supported.In study II, re-exposure to COC induced mood symptoms de novo in women with a previous history of COC-induced adverse mood. Women treated with COC reported increased levels of mood symptoms both as compared to before treatment, and as compared to the placebo group. There was a relatively strong correlation between depressive scores before and during treatment. The effects of repeated COC administration on subjective measures and brain function were however dissociated with increased aversive experiences accompanied by reduced reactivity in the insular cortex.
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| 2. |
- Struckmann, Wiebke, 1991-
(författare)
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The effect of intermittent theta-burst stimulation over the dorsomedial prefrontal cortext on brain activity in depression
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Repetitive transcranial magnetic stimulation is an emerging alternative for treatment-resistant depression, with ongoing developments in stimulation protocols and treatment targets. As such, intermittent theta-burst stimulation (iTBS) delivered over the dorsomedial prefrontal cortex (dmPFC) has shown promise, however establishing a need for neuroimaging studies to further understand the treatment mechanisms. This thesis aims to explore the effects of dmPFC-iTBS on brain activity in depression, using data from a randomized controlled trial and two add-on brain imaging studies with shared methodology. Study I investigated the prefrontal blood oxygenation (oxy-Hb) response during, as well as before and after iTBS sessions at the first, fifth, and final day of treatment. Oxy-Hb was assessed using functional near-infrared spectroscopy (fNIRS). Study II examined patients’ cognitive performance and concurrent prefrontal oxy-Hb before and after a full iTBS treatment course, again using fNIRS. The patient data were also compared to a sample of healthy controls. Study III assessed whether iTBS modulates functional brain activity during an emotional picture anticipation paradigm, using functional magnetic resonance imaging (fMRI). Study IV investigated the functional connectivity of the brain network behind the oxy-Hb response observed in study I. This was done by using the fNIRS optode locations as seeds in a resting-state fMRI analysis before and after a full iTBS treatment course. In summary, brain activity was modulated by iTBS both in an acute and delayed matter. Patients receiving active iTBS had increased prefrontal oxy-Hb levels during the fifth and final iTBS session, suggesting that this modulation was being built up during the treatment course (study I). Resting-state functional connectivity of this prefrontal cortex region to the insula or, when adding oxy-Hb change as a regressor, the posterior parietal cortex was modulated after active, but not sham, iTBS (study IV). Likewise, amygdala activation during exposure to picture stimuli of negative valence was reduced after active, but not sham, iTBS (study III). While patients displayed cognitive deficits compared to healthy controls before treatment start, active iTBS did not alter their cognitive performance or concurrent prefrontal oxy-Hb (study II).
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