@article{BiehlMerzDresleretal.2016,
  author    = {Biehl, Stefanie C. and Merz, Christian J. and Dresler, Thomas and Heupel, Julia and Reichert, Susanne and Jacob, Christian P. and Deckert, J{\"u}rgen and Herrmann, Martin J.},
  title     = {Increase or Decrease of fMRI Activity in Adult Attention Deficit/ Hyperactivity Disorder: Does It Depend on Task Difficulty?},
  series = {International Journal of Neuropsychopharmacology},
  volume    = {19},
  journal   = {International Journal of Neuropsychopharmacology},
  number    = {10},
  doi       = {10.1093/ijnp/pyw049},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-147551},
  pages     = {pyw049},
  year      = {2016},
  abstract  = {Background: Attention deficit/hyperactivity disorder has been shown to affect working memory, and fMRI studies in children and adolescents with attention deficit/hyperactivity disorder report hypoactivation in task-related attentional networks. However, studies with adult attention deficit/hyperactivity disorder patients addressing this issue as well as the effects of clinically valid methylphenidate treatment are scarce. This study contributes to closing this gap. Methods: Thirty-five adult patients were randomized to 6 weeks of double-blind placebo or methylphenidate treatment. Patients completed an fMRI n-back working memory task both before and after the assigned treatment, and matched healthy controls were tested and compared to the untreated patients. Results: There were no whole-brain differences between any of the groups. However, when specified regions of interest were investigated, the patient group showed enhanced BOLD responses in dorsal and ventral areas before treatment. This increase was correlated with performance across all participants and with attention deficit/hyperactivity disorder symptoms in the patient group. Furthermore, we found an effect of treatment in the right superior frontal gyrus, with methylphenidate-treated patients exhibiting increased activation, which was absent in the placebo-treated patients. Conclusions: Our results indicate distinct activation differences between untreated adult attention deficit/hyperactivity disorder patients and matched healthy controls during a working memory task. These differences might reflect compensatory efforts by the patients, who are performing at the same level as the healthy controls. We furthermore found a positive effect of methylphenidate on the activation of a frontal region of interest. These observations contribute to a more thorough understanding of adult attention deficit/hyperactivity disorder and provide impulses for the evaluation of therapy-related changes.},
  language  = {en}
}
@article{GramAlbertovaSchirmeretal.2022,
  author    = {Gram, Maximilian and Albertova, P. and Schirmer, V. and Blaimer, M. and Gamer, M. and Herrmann, M. J. and Nordbeck, P. and Jakob, P. M.},
  title     = {Towards robust in vivo quantification of oscillating biomagnetic fields using Rotary Excitation based MRI},
  series = {Scientific Reports},
  volume    = {12},
  journal   = {Scientific Reports},
  number    = {1},
  doi       = {10.1038/s41598-022-19275-5},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300862},
  year      = {2022},
  abstract  = {Spin-lock based functional magnetic resonance imaging (fMRI) has the potential for direct spatially-resolved detection of neuronal activity and thus may represent an important step for basic research in neuroscience. In this work, the corresponding fundamental effect of Rotary EXcitation (REX) is investigated both in simulations as well as in phantom and in vivo experiments. An empirical law for predicting optimal spin-lock pulse durations for maximum magnetic field sensitivity was found. Experimental conditions were established that allow robust detection of ultra-weak magnetic field oscillations with simultaneous compensation of static field inhomogeneities. Furthermore, this work presents a novel concept for the emulation of brain activity utilizing the built-in MRI gradient system, which allows REX sequences to be validated in vivo under controlled and reproducible conditions. Via transmission of Rotary EXcitation (tREX), we successfully detected magnetic field oscillations in the lower nano-Tesla range in brain tissue. Moreover, tREX paves the way for the quantification of biomagnetic fields.},
  language  = {en}
}
@article{LischkeHerpertzBergeretal.2017,
  author    = {Lischke, Alexander and Herpertz, Sabine C. and Berger, Christoph and Domes, Gregor and Gamer, Matthias},
  title     = {Divergent effects of oxytocin on (para-)limbic reactivity to emotional and neutral scenes in females with and without borderline personality disorder},
  series = {Social Cognitive and Affective Neuroscience},
  volume    = {12},
  journal   = {Social Cognitive and Affective Neuroscience},
  number    = {11},
  doi       = {10.1093/scan/nsx107},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-173309},
  pages     = {1783-1792},
  year      = {2017},
  abstract  = {Borderline personality disorder (BPD) patients' hypersensitivity for emotionally relevant stimuli has been suggested be due to abnormal activity and connectivity in (para-)limbic and prefrontal brain regions during stimulus processing. The neuropeptide oxytocin has been shown to modulate activity and functional connectivity in these brain regions, thereby optimizing the processing of emotional and neutral stimuli. To investigate whether oxytocin would be capable of attenuating BPD patients' hypersensitivity for such stimuli, we recorded brain activity and gaze behavior during the processing of complex scenes in 51 females with and 48 without BPD after intranasal application of either oxytocin or placebo. We found divergent effects of oxytocin on BPD and healthy control (HC) participants' (para-)limbic reactivity to emotional and neutral scenes: Oxytocin decreased amygdala and insula reactivity in BPD participants but increased it in HC participants, indicating an oxytocin-induced normalization of amygdala and insula activity during scene processing. In addition, oxytocin normalized the abnormal coupling between amygdala activity and gaze behavior across all scenes in BPD participants. Overall, these findings suggest that oxytocin may be capable of attenuating BPD patients' hypersensitivity for complex scenes, irrespective of their valence.},
  language  = {en}
}
@article{ZellerMuellerGutberletetal.2013,
  author    = {Zeller, Mario and M{\"u}ller, Alexander and Gutberlet, Marcel and Nichols, Thomas and Hahn, Dietbert and K{\"o}stler, Herbert and Bartsch, Andreas J.},
  title     = {Boosting BOLD fMRI by K-Space Density Weighted Echo Planar Imaging},
  series = {PLoS ONE},
  journal   = {PLoS ONE},
  doi       = {10.1371/journal.pone.0074501},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-97233},
  year      = {2013},
  abstract  = {Functional magnetic resonance imaging (fMRI) has become a powerful and influential method to non-invasively study neuronal brain activity. For this purpose, the blood oxygenation level-dependent (BOLD) effect is most widely used. T2* weighted echo planar imaging (EPI) is BOLD sensitive and the prevailing fMRI acquisition technique. Here, we present an alternative to its standard Cartesian recordings, i.e. k-space density weighted EPI, which is expected to increase the signal-to-noise ratio in fMRI data. Based on in vitro and in vivo pilot measurements, we show that fMRI by k-space density weighted EPI is feasible and that this new acquisition technique in fact boosted spatial and temporal SNR as well as the detection of local fMRI activations. Spatial resolution, spatial response function and echo time were identical for density weighted and conventional Cartesian EPI. The signal-to-noise ratio gain of density weighting can improve activation detection and has the potential to further increase the sensitivity of fMRI investigations.},
  language  = {en}
}