@article{GulbertiMollHameletal.2015,
  author    = {Gulberti, A. and Moll, C.K.E. and Hamel, W. and Buhmann, C. and Koeppen, J.A. and Boelmans, K. and Zittel, S. and Gerloff, C. and Westphal, M. and Schneider, T.R. and Engel, A.K.},
  title     = {Predictive timing functions of cortical beta oscillations are impaired in Parkinson's disease and influenced by L-DOPA and deep brain stimulation of the subthalamic nucleus Impaired beta-band timing functions in PD},
  series = {NeuroImage: Clinical},
  volume    = {9},
  journal   = {NeuroImage: Clinical},
  doi       = {10.1016/j.nicl.2015.09.013},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-150049},
  pages     = {436-449},
  year      = {2015},
  abstract  = {Cortex-basal ganglia circuits participate in motor timing and temporal perception, and are important for the dynamic configuration of sensorimotor networks in response to exogenous demands. In Parkinson's disease (PD) patients, rhythmic auditory stimulation (RAS) induces motor performance benefits. Hitherto, little is known concerning contributions of the basal ganglia to sensory facilitation and cortical responses to RAS in PD. Therefore, we conducted an EEG study in 12 PD patients before and after surgery for subthalamic nucleus deep brain stimulation (STN-DBS) and in 12 age-matched controls. Here we investigated the effects of levodopa and STN-DBS on resting-state EEG and on the cortical-response profile to slow and fast RAS in a passive-listening paradigm focusing on beta-band oscillations, which are important for auditory-motor coupling. The beta-modulation profile to RAS in healthy participants was characterized by local peaks preceding and following auditory stimuli. In PD patients RAS failed to induce pre-stimulus beta increases. The absence of pre-stimulus beta-band modulation may contribute to impaired rhythm perception in PD. Moreover, post-stimulus beta-band responses were highly abnormal during fast RAS in PD patients. Treatment with levodopa and STN-DBS reinstated a post-stimulus beta-modulation profile similar to controls, while STN-DBS reduced beta-band power in the resting-state. The treatment-sensitivity of beta oscillations suggests that STN-DBS may specifically improve timekeeping functions of cortical beta oscillations during fast auditory pacing.},
  language  = {en}
}
@article{CanessaPozziArnulfoetal.2016,
  author    = {Canessa, Andrea and Pozzi, Nicol{\`o} G. and Arnulfo, Gabriele and Brumberg, Joachim and Reich, Martin M. and Pezzoli, Gianni and Ghilardi, Maria F. and Matthies, Cordula and Steigerwald, Frank and Volkmann, Jens and Isaias, Ioannis U.},
  title     = {Striatal Dopaminergic Innervation Regulates Subthalamic Beta-Oscillations and Cortical-Subcortical Coupling during Movements: Preliminary Evidence in Subjects with Parkinson's Disease},
  series = {Frontiers in Human Neuroscience},
  volume    = {10},
  journal   = {Frontiers in Human Neuroscience},
  number    = {611},
  doi       = {10.3389/fnhum.2016.00611},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164061},
  year      = {2016},
  abstract  = {Activation of the basal ganglia has been shown during the preparation and execution of movement. However, the functional interaction of cortical and subcortical brain areas during movement and the relative contribution of dopaminergic striatal innervation remains unclear. We recorded local field potential (LFP) activity from the subthalamic nucleus (STN) and high-density electroencephalography (EEG) signals in four patients with Parkinson's disease (PD) off dopaminergic medication during a multi-joint motor task performed with their dominant and non-dominant hand. Recordings were performed by means of a fully-implantable deep brain stimulation (DBS) device at 4 months after surgery. Three patients also performed a single-photon computed tomography (SPECT) with [123I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane (FP-CIT) to assess striatal dopaminergic innervation. Unilateral movement execution led to event-related desynchronization (ERD) followed by a rebound after movement termination event-related synchronization (ERS) of oscillatory beta activity in the STN and primary sensorimotor cortex of both hemispheres. Dopamine deficiency directly influenced movement-related beta-modulation, with greater beta-suppression in the most dopamine-depleted hemisphere for both ipsi- and contralateral hand movements. Cortical-subcortical, but not interhemispheric subcortical coherencies were modulated by movement and influenced by striatal dopaminergic innervation, being stronger in the most dopamine-depleted hemisphere. The data are consistent with a role of dopamine in shielding subcortical structures from an excessive cortical entrapment and cross-hemispheric coupling, thus allowing fine-tuning of movement.},
  language  = {en}
}