TY - JOUR A1 - Pasos, Uri E. Ramirez A1 - Steigerwald, Frank A1 - Reich, Martin M. A1 - Matthies, Cordula A1 - Volkmann, Jens A1 - Reese, René T1 - 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 JF - Frontiers in Human Neuroscience N2 - 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. KW - Parkinson’s disease KW - subthalamic nucleus KW - deep brain stimulation KW - local field potentials KW - dopamine KW - movement Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-201540 VL - 13 IS - 223 ER - TY - THES A1 - Ramirez Pasos, Uri Eduardo T1 - Subthalamic Nucleus Neural Synchronization and Connectivity during Limbic Processing of Emotional Pictures: Evidence from Invasive Recordings in Patients with Parkinson's Disease T1 - Synchronisierung und Konnektivität des Nucleus subthalamicus während limbischer Bearbeitung affektiver Bilder: Evidenz aus invasiven Aufzeichnungen in Patienten mit Morbus Parkinson N2 - In addition to bradykinesia and tremor, patients with Parkinson’s disease (PD) are known to exhibit non-motor symptoms such as apathy and hypomimia but also impulsivity in response to dopaminergic replacement therapy. Moreover, a plethora of studies observe differences in electrocortical and autonomic responses to both visual and acoustic affective stimuli in PD subjects compared to healthy controls. This suggests that the basal ganglia (BG), as well as the hyperdirect pathway and BG thalamocortical circuits, are involved in affective processing. Recent studies have shown valence and dopamine-dependent changes in synchronization in the subthalamic nucleus (STN) in PD patients during affective tasks. This thesis investigates the role of dopamine, valence, and laterality in STN electrophysiology by analyzing event-related potentials (ERP), synchronization, and inter-hemispheric STN connectivity. STN recordings were obtained from PD patients with chronically implanted electrodes for deep brain stimulation during a passive affective picture presentation task. The STN exhibited valence-dependent ERP latencies and lateralized ‘high beta’ (28–40 Hz) event-related desynchronization. This thesis also examines the role of dopamine, valence, and laterality on STN functional connectivity with the anterior cingulate cortex (ACC) and the amygdala. The activity of these limbic structures was reconstructed using simultaneously recorded electroencephalographic signals. While the STN was found to establish early coupling with both structures, STN-ACC coupling in the ‘alpha’ range (7–11 Hz) and uncoupling in the ‘low beta’ range (14–21 Hz) were lateralized. Lateralization was also observed at the level of synchrony in both reconstructed sources and for ACC ERP amplitude, whereas dopamine modulated ERP latency in the amygdala. These results may deepen our current understanding of the STN as a limbic node within larger emotional-motor networks in the brain.
 N2 - Neben Bradykinese und Tremor weisen Patienten mit Morbus Parkinson (PD) bekannterweise nicht-motorische Symptome auf wie Apathie und Hypomimie, aber auch Impulsivität, welche durch Dopaminersatztherapien bedingt ist. Viele Studien belegen außerdem Unterschiede von kortikalen und autonomen Reaktionen auf sowohl visuelle als auch akustische Reize bei Patienten mit PD im Vergleich zu gesunden Kontrollgruppen. Dies legt nahe, dass sich die Basalganglien (BG), und auch die hyperdirekte Verbindung sowie die BG-thalamokortikalen Schleifen, an der Affektbearbeitung beteiligen. Jüngere Studien haben Valenz- und Dopamin-bedingte Veränderungen der Synchronisierung im Nucleus subthalamicus (STN) von Parkinson-Patienten bei affektiven Aufgaben belegt. Diese Promotionsarbeit untersucht die Rolle von Dopamin, Valenz und Lateralität in der STN-Elektrophysiologie mittels Analysen von ereigniskorrelierten Potentialen (ERP), Synchronisierung und interhemisphärischer funktioneller Konnektivität. STN-Aufzeichnungen wurden von Patienten mit dauerhaft implantierten Elektroden für die Tiefenhirnstimulation während einer passiven Aufgabe abgeleitet, bei den ihnen Bilder mit emotionalen Inhalten gezeigt wurden. Der STN wies Valenz-bedingte ERP-Latenz und lateralisierte ereigniskorrelierte Desynchronisierung in ‘hohem Beta’ (28–40 Hz) auf. Diese Dissertation untersucht auch die Rolle von Dopamin, Valenz und Lateralität bezüglich der funktionellen Konnektivität zwischen dem STN und dem Gyrus cinguli pars anterior (ACC) sowie der Amygdala. Die Aktivität dieser Strukturen wurde aus simultanen elektroenzephalographischen Aufzeichnungen rekonstruiert. Obwohl eine STN-Kopplung mit beiden Strukturen auftritt, war die STN-ACC-Kopplung im ‘Alpha’- Bereich (7–11 Hz) und die Entkopplung im ‘niedrigen Beta’-Bereich (14–21 Hz) lateralisiert. Lateralisierung wurde auch an der Synchronisierung in beiden rekonstruierten Quellen und an der ACC-ERP-Amplitude festgestellt, wohingegen Dopamin die ERP-Latenz in der Amygdala modulierte. Diese Ergebnisse mögen das gegenwärtige Wissen vom STN als limbischem Knoten innerhalb größerer affektiv-motorischer Schleifen im Gehirn vertiefen. KW - Nucleus subthalamicus KW - subthalamic nucleus KW - Emotionales Verhalten KW - functional connectivity KW - oscillations KW - emotion KW - Affekt KW - Elektrophysiologie Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-169850 ER -