title: Power fluctuations in beta and gamma frequencies in rat globus pallidus: association with specific phases of slow oscillations and differential modulation by dopamine D1 and D2 receptors.
abstract: Modulation of oscillatory activity through basal ganglia-cortical loops in specific frequency bands is thought to reflect specific functional states of neural networks. A specific negative correlation between beta and gamma sub-bands has been demonstrated in human basal ganglia and may be key for normal basal ganglia function. However, these studies were limited to Parkinson's disease patients. To confirm that this interaction is a feature of normal basal ganglia, we recorded local field potential (LFP) from electrodes in globus pallidus (GP) of intact rats. We found significant negative correlation between specific frequencies within gamma (≈ 60 Hz) and beta (≈ 14 Hz) bands. Furthermore, we show that fluctuations in power at these frequencies are differentially nested within slow (≈ 3 Hz) oscillations in the delta band, showing maximum power at distinct and different phases of delta. These results suggest a hierarchical organization of LFP frequencies in the rat GP, in which a low-frequency signal in the basal ganglia can predict the timing and interaction of power fluctuations across higher frequencies. Finally, we found that dopamine D(1) and D(2) receptor antagonists differentially affected power in gamma and beta bands and also had different effects on correlation between them and the nesting within delta, indicating an important role for endogenous dopamine acting on direct and indirect pathway neurons in the maintenance of the hierarchical organization of frequency bands. Disruption of this hierarchical organization and subsequent disordered beta-gamma balance in basal ganglia disorders such as Parkinson's disease may be important in the pathogenesis of their symptoms.
authors.affiliation: Department of Anatomy and Structural Biology, School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Cyril
authors.initials: C
authors.lastname: Dejean
authors.forename: Gordon
authors.initials: G
authors.lastname: Arbuthnott
authors.forename: Jeffery R
authors.initials: JR
authors.lastname: Wickens
authors.forename: Catherine
authors.initials: C
authors.lastname: Le Moine
authors.forename: Thomas
authors.initials: T
authors.lastname: Boraud
authors.forename: Brian I
authors.initials: BI
authors.lastname: Hyland
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D004594:Electrophysiology; D005917:Globus Pallidus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D020891:Raclopride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000378:metabolism*
chemical_list: D001552:Benzazepines; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C534628:SCH 23390; D020891:Raclopride