title: Reciprocal interactions between oscillatory activities of different frequencies in the subthalamic region of patients with Parkinson's disease.
abstract: Synchronization of neuronal activity evident in the local field potential (LFP) recorded in the subthalamic region of patients with Parkinson's disease occurs at low frequencies (< 30 Hz) and, in some patients following treatment with levodopa, at high frequencies between 65 and 85 Hz. Here we investigate the functional relationship between these different activities by determining whether spontaneous fluctuations in their strength are correlated across time. To this end, we analysed recordings of LFPs from macroelectrodes inserted in the subthalamic area of 16 patients with Parkinson's disease, after treatment with anti-parkinsonian medication. Time-evolving autospectra of LFPs with significant 65-85 Hz peaks (from 21 sides) were computed and correlations between frequency components determined over time. LFP activity in the 5-32 Hz band was significantly negatively correlated with that in the 65-85 Hz band in data averaged across all 21 sides, as well as in 15 (71%) of the individual records. Negative correlations were relatively selective for interactions between these frequency bands and occurred over time epochs of as little as 40 s. They occurred about 50 min after levodopa and were recorded concurrently with contralateral levodopa-induced dyskinesias in all but four cases. Positive correlations were not seen between activities in the 5-32 Hz and 65-85 Hz bands. The spontaneous negative correlations suggest a reciprocal relationship between population synchrony in the high- and low-frequency ranges, and raise the possibility that spontaneous fluctuations in the balance between these activities may contribute to levodopa-induced dyskinesias.
authors: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, UK.
authors: Noa
authors: N
authors: Fogelson
authors: Alek
authors: A
authors: Pogosyan
authors: Andrea A
authors: AA
authors: Kühn
authors: Andreas
authors: A
authors: Kupsch
authors: Gerard
authors: G
authors: van Bruggen
authors: Hans
authors: H
authors: Speelman
authors: Marina
authors: M
authors: Tijssen
authors: Angelo
authors: A
authors: Quartarone
authors: Angelo
authors: A
authors: Insola
authors: Paolo
authors: P
authors: Mazzone
authors: Vincenzo
authors: V
authors: Di Lazzaro
authors: Patricia
authors: P
authors: Limousin
authors: Peter
authors: P
authors: Brown
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000328:Adult; D000368:Aged; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology*; D015259:Dopamine Agents / Q000009:adverse effects; D004409:Dyskinesia, Drug-Induced / Q000503:physiopathology; D004594:Electrophysiology; D005260:Female; D006801:Humans; D007980:Levodopa / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000187:drug effects / Q000503:physiopathology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010300:Parkinson Disease / Q000503:physiopathology*; D020531:Subthalamic Nucleus / Q000187:drug effects / Q000503:physiopathology*
chemical_list: D015259:Dopamine Agents; D007980:Levodopa