@article{Gonzalez‐EscamillaMuthuramanReichetal.2019,
  author    = {Gonzalez-Escamilla, Gabriel and Muthuraman, Muthuraman and Reich, Martin M. and Koirala, Nabin and Riedel, Christian and Glaser, Martin and Lange, Florian and Deuschl, G{\"u}nther and Volkmann, Jens and Groppa, Sergiu},
  title     = {Cortical network fingerprints predict deep brain stimulation outcome in dystonia},
  series = {Movement Disorders},
  volume    = {34},
  journal   = {Movement Disorders},
  number    = {10},
  doi       = {10.1002/mds.27808},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-213532},
  pages     = {1536 -- 1545},
  year      = {2019},
  abstract  = {Background Deep brain stimulation (DBS) is an effective evidence-based therapy for dystonia. However, no unequivocal predictors of therapy responses exist. We investigated whether patients optimally responding to DBS present distinct brain network organization and structural patterns. Methods From a German multicenter cohort of 82 dystonia patients with segmental and generalized dystonia who received DBS implantation in the globus pallidus internus, we classified patients based on the clinical response 3 years after DBS. Patients were assigned to the superior-outcome group or moderate-outcome group, depending on whether they had above or below 70\% motor improvement, respectively. Fifty-one patients met MRI-quality and treatment response requirements (mean age, 51.3 ± 13.2 years; 25 female) and were included in further analysis. From preoperative MRI we assessed cortical thickness and structural covariance, which were then fed into network analysis using graph theory. We designed a support vector machine to classify subjects for the clinical response based on individual gray-matter fingerprints. Results The moderate-outcome group showed cortical atrophy mainly in the sensorimotor and visuomotor areas and disturbed network topology in these regions. The structural integrity of the cortical mantle explained about 45\% of the DBS stimulation amplitude for optimal response in individual subjects. Classification analyses achieved up to 88\% of accuracy using individual gray-matter atrophy patterns to predict DBS outcomes. Conclusions The analysis of cortical integrity, informed by group-level network properties, could be developed into independent predictors to identify dystonia patients who benefit from DBS.},
  language  = {en}
}
@article{PasosSteigerwaldReichetal.2019,
  author    = {Pasos, Uri E. Ramirez and Steigerwald, Frank and Reich, Martin M. and Matthies, Cordula and Volkmann, Jens and Reese, Ren{\´e}},
  title     = {Levodopa modulates functional connectivity in the upper beta band between bubthalamic nucleus and muscle activity in tonic and phasic motor activity patterns in Parkinson's disease},
  series = {Frontiers in Human Neuroscience},
  volume    = {13},
  journal   = {Frontiers in Human Neuroscience},
  number    = {223},
  doi       = {10.3389/fnhum.2019.00223},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201540},
  year      = {2019},
  abstract  = {Introduction: Striatal dopamine depletion disrupts basal ganglia function and causes Parkinson's disease (PD). The pathophysiology of the dopamine-dependent relationship between basal ganglia signaling and motor control, however, is not fully understood. We obtained simultaneous recordings of local field potentials (LFPs) from the subthalamic nucleus (STN) and electromyograms (EMGs) in patients with PD to investigate the impact of dopaminergic state and movement on long-range beta functional connectivity between basal ganglia and lower motor neurons. Methods: Eight PD patients were investigated 3 months after implantation of a deep brain stimulation (DBS)-system capable of recording LFPs via chronically-implanted leads (Medtronic, ACTIVA PC+S®). We analyzed STN spectral power and its coherence with EMG in the context of two different movement paradigms (tonic wrist extension vs. alternating wrist extension and flexion) and the effect of levodopa (L-Dopa) intake using an unbiased data-driven approach to determine regions of interest (ROI). Results: Two ROIs capturing prominent coherence within a grand average coherogram were identified. A trend of a dopamine effect was observed for the first ROI (50-150 ms after movement start) with higher STN-EMG coherence in medicated patients. Concerning the second ROI (300-500 ms after movement start), an interaction effect of L-Dopa medication and movement task was observed with higher coherence in the isometric contraction task compared to alternating movements in the medication ON state, a pattern which was reversed in L-Dopa OFF. Discussion: L-Dopa medication may normalize functional connectivity between remote structures of the motor system with increased upper beta coherence reflecting a physiological restriction of the amount of information conveyed between remote structures. This may be necessary to maintain simple movements like isometric contraction. Our study adds dynamic properties to the complex interplay between STN spectral beta power and the nucleus' functional connectivity to remote structures of the motor system as a function of movement and dopaminergic state. This may help to identify markers of neuronal activity relevant for more individualized programming of DBS therapy.},
  language  = {en}
}
@article{SchuhmannStollBohretal.2019,
  author    = {Schuhmann, Michael K. and Stoll, Guido and Bohr, Arne and Volkmann, Jens and Fluri, Felix},
  title     = {Electrical stimulation of the mesencephalic locomotor region attenuates neuronal loss and cytokine expression in the perifocal region of photothrombotic stroke in rats},
  series = {International Journal of Molecular Science},
  volume    = {20},
  journal   = {International Journal of Molecular Science},
  number    = {9},
  issn      = {1422-0067},
  doi       = {10.3390/ijms20092341},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201355},
  year      = {2019},
  abstract  = {Deep brain stimulation of the mesencephalic locomotor region (MLR) improves the motor symptoms in Parkinson's disease and experimental stroke by intervening in the motor cerebral network. Whether high-frequency stimulation (HFS) of the MLR is involved in non-motor processes, such as neuroprotection and inflammation in the area surrounding the photothrombotic lesion, has not been elucidated. This study evaluates whether MLR-HFS exerts an anti-apoptotic and anti-inflammatory effect on the border zone of cerebral photothrombotic stroke. Rats underwent photothrombotic stroke of the right sensorimotor cortex and the implantation of a microelectrode into the ipsilesional MLR. After intervention, either HFS or sham stimulation of the MLR was applied for 24 h. The infarct volumes were calculated from consecutive brain sections. Neuronal apoptosis was analyzed by TUNEL staining. Flow cytometry and immunohistochemistry determined the perilesional inflammatory response. Neuronal apoptosis was significantly reduced in the ischemic penumbra after MLR-HFS, whereas the infarct volumes did not differ between the groups. MLR-HFS significantly reduced the release of cytokines and chemokines within the ischemic penumbra. MLR-HFS is neuroprotective and it reduces pro-inflammatory mediators in the area that surrounds the photothrombotic stroke without changing the number of immune cells, which indicates that MLR-HFS enables the function of inflammatory cells to be altered on a molecular level.},
  language  = {en}
}
@article{SchuhmannStollPappetal.2019,
  author    = {Schuhmann, Michael K. and Stoll, Guido and Papp, Lena and Bohr, Arne and Volkmann, Jens and Fluri, Felix},
  title     = {Electrical stimulation of the mesencephalic locomotor region has no impact on blood-brain barrier alterations after cerebral photothrombosis in rats},
  series = {International Journal of Molecular Science},
  volume    = {20},
  journal   = {International Journal of Molecular Science},
  number    = {16},
  issn      = {1422-0067},
  doi       = {10.3390/ijms20164036},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201284},
  year      = {2019},
  abstract  = {Blood-brain barrier (BBB) disruption is a critical event after ischemic stroke, which results in edema formation and hemorrhagic transformation of infarcted tissue. BBB dysfunction following stroke is partly mediated by proinflammatory agents. We recently have shown that high frequency stimulation of the mesencephalic locomotor region (MLR-HFS) exerts an antiapoptotic and anti-inflammatory effect in the border zone of cerebral photothrombotic stroke in rats. Whether MLR-HFS also has an impact on BBB dysfunction in the early stage of stroke is unknown. In this study, rats were subjected to photothrombotic stroke of the sensorimotor cortex and implantation of a stimulating microelectrode into the ipsilesional MLR. Thereafter, either HFS or sham stimulation of the MLR was applied for 24 h. After scarifying the rats, BBB disruption was assessed by determining albumin extravasation and tight junction integrity (claudin 3, claudin 5, and occludin) using Western blot analyses and immunohistochemistry. In addition, by applying zymography, expression of pro-metalloproteinase-9 (pro-MMP-9) was analyzed. No differences were found regarding infarct size and BBB dysfunction between stimulated and unstimulated animals 24 h after induction of stroke. Our results indicate that MLR-HFS neither improves nor worsens the damaged BBB after stroke. Attenuating cytokines/chemokines in the perilesional area, as mediated by MLR-HFS, tend to play a less significant role in preventing the BBB integrity.},
  language  = {en}
}