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"Stark, R."

Ergebnisse 24 Einträge

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Walter, B., Sadlo, M. N., Kupfer, J., Niemeier, V., Brosig, B., Stark, R., Vaitl, D., & Gieler, U. (2005). Brain Activation by Histamine Prick Test-Induced Itch. Journal of Investigative Dermatology, 125(2), 380–382. https://doi.org/10.1111/j.0022-202X.2005.23817.x

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Zentgraf, K., Stark, R., Reiser, M., Künzell, S., Schienle, A., Kirsch, P., Walter, B., Vaitl, D., & Munzert, J. (2005). Differential activation of pre-SMA and SMA proper during action observation: Effects of instructions. NeuroImage, 26(3), 662–672. https://doi.org/10.1016/j.neuroimage.2005.02.015

Many neurophysiological studies give evidence for a matching system between action observation and imitation. We used functional MRI to investigate the effects of different instructions for observing identical stimuli of whole-body gymnastics movements. The imitative-like observation mode asked normal human participants to observe the sequence containing repetitive parts and to subsequently imagine the observed movements in the first-person perspective. The evaluative observation mode asked the participants to carefully observe and judge movement accuracy and consistency in the repetitive sequence. We hypothesized that the supplementary motor area would be specifically involved in performing the observational tasks. Results indicate that the SMA proper is generally activated during observation of whole-body gymnastic movements and shows pronounced activation in imitative-like observation mode. Pre-SMA activity can be differentially modulated by instructions related to the observation task.

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Klucken, T., Schweckendiek, J., Koppe, G., Merz, C. J., Kagerer, S., Walter, B., Sammer, G., Vaitl, D., & Stark, R. (2012). Neural correlates of disgust- and fear-conditioned responses. Neuroscience, 201, 209–218. https://doi.org/10.1016/j.neuroscience.2011.11.007

The understanding of individual differences in responses to disgusting stimuli is important to gain more insight into the development of certain psychiatric disorders. The aim of this study was to investigate conditioned disgust responses, its potential overlap with conditioned fear responses (CRs) and the influence of disgust sensitivity on blood oxygen level-dependent responses. Yet even though current studies report evidence that disgust sensitivity is a vulnerability factor, the knowledge about the underlying neural mechanisms remains very limited. Two groups were exposed either to a disgust- or a fear-conditioning paradigm. Using functional magnetic resonance imaging, we identified a conjoint activated network including the cingulate cortex, the nucleus accumbens, the orbitofrontal cortex, and the occipital cortex within the disgust- and the fear-conditioning group. Moreover, we report evidence of increased insula activation in the disgust-conditioning group. In addition, functional connectivity analysis revealed increased interconnections, most pronounced within the insula in the high disgust sensitivity group compared with the low disgust sensitivity group. The conjunction results suggest that the conditioned responses in disgust and fear conditioning recruit the same neural network, implicating that different conditioned responses of aversive learning depend on a common neural network. Increased insula activation within the disgust-conditioning group might be attributable to heightened interoceptive processes, which might be more pronounced in disgust. Finally, the findings regarding disgust sensitivity are discussed with respect to vulnerability factors for certain psychiatric disorders.
Stark, R., Bauer, E., Merz, C. J., Zimmermann, M., Reuter, M., Plichta, M. M., Kirsch, P., Lesch, K. P., Fallgatter, A. J., Vaitl, D., & Herrmann, M. J. (2011). ADHD related behaviors are associated with brain activation in the reward system. Neuropsychologia, 49(3), 426–434. https://doi.org/10.1016/j.neuropsychologia.2010.12.012

Neuroimaging studies on attention-deficit/hyperactivity disorder (ADHD) suggest dysfunctional reward processing, with hypo-responsiveness during reward anticipation in the reward system including the nucleus accumbens (NAcc). In this study, we investigated the association between ADHD related behaviors and the reward system using functional magnetic resonance imaging in a non-clinical sample. Participants were 31 healthy, female undergraduate students with varying levels of self-reported ADHD related behaviors measured by the adult ADHD self-report scale. The anticipation of different types of reward was investigated: monetary reward, punishment avoidance, and verbal feedback. All three reward anticipation conditions were found to be associated with increased brain activation in the reward system, with the highest activation in the monetary reward anticipation condition, followed by the punishment avoidance anticipation condition, and the lowest activation in the verbal feedback anticipation condition. Most interestingly, in all three conditions, NAcc activation was negatively correlated with ADHD related behaviors. In conclusion, our results from a non-clinical sample are in accordance with reported deficits in the reward system in ADHD patients: the higher the number and severity of ADHD related behaviors, the lower the neural responses in the dopaminergic driven reward anticipation task. Thus, our data support current aetiological models of ADHD which assume that deficits in the reward system might be responsible for many of the ADHD related behaviors.

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Last update from database: 19.12.25, 08:32 (UTC)

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