Publications (48) View all
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Article: Context insensitivity during positive and negative emotional expectancy in depression assessed with functional magnetic resonance imaging.
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ABSTRACT: Patients with depression show an enhanced preoccupation with negative expectations and are often unable to look forward to positive events. Here we studied anticipatory emotional processes in unmedicated depressed patients using functional magnetic resonance imaging. Consistent with a negative processing bias, we hypothesized enhanced responses to negative and attenuated responses to positive expectancy cues in brain areas associated with emotional expectancy. Participants comprised 19 drug-free depressed patients and 19 matched healthy control subjects who viewed affective photographs. Pictures were preceded by an expectancy cue which signaled the emotional valence of the upcoming picture in half of the trials. Depressed patients showed attenuated blood-oxygen-level-dependent responses in the left lateral prefrontal cortex (inferior frontal gyrus, Brodmann area 44) during positive expectancy and-contrary to our hypothesis-in the right lateral orbitofrontal cortex (middle frontal gyrus, Brodmann area 47) during negative expectancy. This attenuation was specific for the anticipation (as opposed to the perception) of emotional pictures and correlated with a clinical measure of depressive symptoms. The observed attenuation suggests emotion-context insensitivity rather than a negative processing bias during anticipatory emotional processes in depression. This hyporeactivity may contribute to clinical features like anergia, apathy, and loss of motivation in the context of both positive and negative incentives.Psychiatry research. 03/2013; -
Dataset: Northoff et.al.Self-Referential Processing-Neuroimage '06
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Article: Hemispheric asymmetry for affective stimulus processing in healthy subjects-a FMRI study.
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ABSTRACT: While hemispheric specialization of language processing is well established, lateralization of emotion processing is still under debate. Several conflicting hypotheses have been proposed, including right hemisphere hypothesis, valence asymmetry hypothesis and region-specific lateralization hypothesis. However, experimental evidence for these hypotheses remains inconclusive, partly because direct comparisons between hemispheres are scarce. The present fMRI study systematically investigated functional lateralization during affective stimulus processing in 36 healthy participants. We normalized our functional data on a symmetrical template to avoid confounding effects of anatomical asymmetries. Direct comparison of BOLD responses between hemispheres was accomplished taking two approaches: a hypothesis-driven region of interest analysis focusing on brain areas most frequently reported in earlier neuroimaging studies of emotion; and an exploratory whole volume analysis contrasting non-flipped with flipped functional data using paired t-test. The region of interest analysis revealed lateralization towards the left in the medial prefrontal cortex (BA 10) during positive stimulus processing; while negative stimulus processing was lateralized towards the right in the dorsolateral prefrontal cortex (BA 9 & 46) and towards the left in the amygdala and uncus. The whole brain analysis yielded similar results and, in addition, revealed lateralization towards the right in the premotor cortex (BA 6) and the temporo-occipital junction (BA 19 & 37) during positive stimulus processing; while negative stimulus processing showed lateralization towards the right in the temporo-parietal junction (BA 37,39,42) and towards the left in the middle temporal gyrus (BA 21). Our data suggests region-specific functional lateralization of emotion processing. Findings show valence asymmetry for prefrontal cortical areas and left-lateralized negative stimulus processing in subcortical areas, in particular, amygdala and uncus.PLoS ONE 01/2012; 7(10):e46931. · 4.09 Impact Factor -
Article: Hyporeactivity of ventral striatum towards incentive stimuli in unmedicated depressed patients normalizes after treatment with escitalopram.
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ABSTRACT: Major Depressive Disorder (MDD) involves deficits in the reward system. While neuroimaging studies have focused on affective stimulus processing, few investigations have directly addressed deficits in the anticipation of incentives. We examined neural responses during gain and loss anticipation in patients with MDD before and after treatment with a selective serotonin reuptake inhibitor (SSRI). Fifteen adults with MDD and 15 healthy participants, matched for age, verbal IQ and smoking habits, were investigated in a functional magnetic resonance imaging (fMRI) study using a monetary incentive delay task. Patients were scanned drug-free and after 6 weeks of open-label treatment with escitalopram; controls were scanned twice at corresponding time points. We compared the blood oxygenation level dependent (BOLD) response during the anticipation of gain and loss with a neutral condition. A repeated measures ANOVA was calculated to identify effects of group (MDD vs. controls), time (first vs. second scan) and group-by-time interaction. Severity of depression was measured with the Hamilton Rating Scale of Depression and the Beck Depression Inventory. MDD patients showed significantly less ventral striatal activation during anticipation of gain and loss compared with controls before, but not after, treatment. There was a significant group-by-time interaction during anticipation of loss in the left ventral striatum due to a signal increase in patients after treatment. Ventral striatal hyporesponsiveness was associated with the severity of depression and in particular anhedonic symptoms. These findings suggest that MDD patients show ventral striatal hyporesponsiveness during incentive cue processing, which normalizes after successful treatment.Journal of Psychopharmacology 09/2011; 26(5):677-88. · 3.04 Impact Factor -
Article: Long-term treatment with supraphysiological doses of thyroid hormone in affective disorders - effects on bone mineral density.
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ABSTRACT: To investigate the long-term effects of supraphysiological, TSH suppressive doses of levothyroxine (TSDL) on bone mineral density (BMD) in patients with affective disorders during an average treatment duration of 69 months. In 22 patients, BMD of the spine (lumbar vertebrae L1-4) and femur (femoral neck) was measured by dual energy X-ray absorptiometry (DXA). Forty (40) measurements from the prior study and 48 new follow-up measurements were included. BMD was expressed as Z-scores as a population standard reference. We used a linear mixed model to investigate the duration of TSDL as an explanatory factor for change in BMD compared to an age and gender matched reference population. We found no significant differences in bone loss between the study and the reference population. The estimated non-significant decrease in Z-score compared to the reference population found was: a) lumbar spine (L1-4): -0.00069/month (p=0.9759) b) neck region of femur: -0.01405/month (p=0.4436). We did not find the factors age, thyroxine-dose or postmenopausal state as predictors for a decline in BMD. Small sample size, no bone density assessment prior to treatment with TSDL, no patient control group with mood disorders who did not receive TSDL, variable bone density follow-up intervals. This study did not demonstrate evidence that long-term treatment of affectively ill patients with TSDL accelerates loss of BMD compared to an age- and gender-matched reference population.Journal of affective disorders 07/2011; 136(1-2):e89-94. · 3.76 Impact Factor
