title: Short- and long-term dopamine depletion causes enhanced beta oscillations in the cortico-basal ganglia loop of parkinsonian rats.
abstract: Abnormally enhanced beta oscillations have been found in deep brain recordings from human Parkinson's disease (PD) patients and in animal models of PD. Recent correlative evidence suggests that beta oscillations are related to disease-specific symptoms such as akinesia and rigidity. However, this hypothesis has also been repeatedly questioned by studies showing no changes in beta power in animal models using an acute pharmacologic dopamine blockade. To further investigate the temporal dynamics of exaggerated beta synchrony in PD, we investigated the reserpine model, which is characterized by an acute and stable disruption of dopamine transmission, and compared it to the chronic progressive 6-hydroxydopamine (6-OHDA) model. Using simultaneous electrophysiological recordings in urethane anesthetized rats from the primary motor cortex, the subthalamic nucleus and the reticulate part of the substantia, we found evidence for enhanced beta oscillations in the basal ganglia of both animal models during the activated network state. In contrast to 6-OHDA, reserpine treated animals showed no involvement of primary motor cortex. Notably, beta coherence levels between primary motor cortex and basal ganglia nuclei were elevated in both models. Although both models exhibited elevated beta power and coherence levels, they differed substantially in respect to their mean peak frequency: while the 6-OHDA peak was located in the low beta range (17Hz), the reserpine peak was centered at higher beta frequencies (27Hz). Our results further support the hypothesis of an important pathophysiological relation between enhanced beta activity and akinesia in parkinsonism.
authors.affiliation: Charité University Medicine Berlin, Department of Neurology, Movement Disorder and Neuromodulation Unit, Berlin, Germany.
authors.forename: Maximilian H
authors.initials: MH
authors.lastname: Beck
authors.affiliation: Charité University Medicine Berlin, Department of Neurology, Movement Disorder and Neuromodulation Unit, Berlin, Germany.
authors.forename: Jens K
authors.initials: JK
authors.lastname: Haumesser
authors.affiliation: Charité University Medicine Berlin, Department of Neurology, Movement Disorder and Neuromodulation Unit, Berlin, Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Kühn
authors.affiliation: Charité University Medicine Berlin, Department of Neurology, Movement Disorder and Neuromodulation Unit, Berlin, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Altschüler
authors.affiliation: Charité University Medicine Berlin, Department of Neurology, Movement Disorder and Neuromodulation Unit, Berlin, Germany.
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Kühn
authors.affiliation: Charité University Medicine Berlin, Department of Neurology, Movement Disorder and Neuromodulation Unit, Berlin, Germany. Electronic address: christoph.van-riesen@charite.de.
authors.forename: Christoph
authors.initials: C
authors.lastname: van Riesen
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001479:Basal Ganglia / Q000187:drug effects / Q000503:physiopathology*; D001611:Beta Rhythm / Q000187:drug effects / Q000502:physiology*; D002540:Cerebral Cortex / Q000187:drug effects / Q000503:physiopathology*; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism*; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000503:physiopathology; D016627:Oxidopamine / Q000633:toxicity; D020734:Parkinsonian Disorders / Q000139:chemically induced / Q000473:pathology* / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D013057:Spectrum Analysis; D013565:Sympatholytics / Q000633:toxicity; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D013565:Sympatholytics; D016627:Oxidopamine; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine
keywords: 6-OHDA; Beta oscillations; Cortico-basal ganglia loop; Gamma oscillations; Parkinson's disease; Reserpine