title: Untangling Cortico-Striatal Connectivity and Cross-Frequency Coupling in L-DOPA-Induced Dyskinesia.
abstract: We simultaneously recorded local field potentials (LFPs) in the primary motor cortex and sensorimotor striatum in awake, freely behaving, 6-OHDA lesioned hemi-parkinsonian rats in order to study the features directly related to pathological states such as parkinsonian state and levodopa-induced dyskinesia. We analyzed the spectral characteristics of the obtained signals and observed that during dyskinesia the most prominent feature was a relative power increase in the high gamma frequency range at around 80 Hz, while for the parkinsonian state it was in the beta frequency range. Here we show that during both pathological states effective connectivity in terms of Granger causality is bidirectional with an accent on the striatal influence on the cortex. In the case of dyskinesia, we also found a high increase in effective connectivity at 80 Hz. In order to further understand the 80-Hz phenomenon, we performed cross-frequency analysis and observed characteristic patterns in the case of dyskinesia but not in the case of the parkinsonian state or the control state. We noted a large decrease in the modulation of the amplitude at 80 Hz by the phase of low frequency oscillations (up to ~10 Hz) across both structures in the case of dyskinesia. This may suggest a lack of coupling between the low frequency activity of the recorded network and the group of neurons active at ~80 Hz.
authors.affiliation: Science for Life Laboratory, School of Computer Science and Communication, KTH Royal Institute of TechnologyStockholm, Sweden; Bernstein Center Freiburg, University of FreiburgFreiburg, Germany.
authors.forename: Jovana J
authors.initials: JJ
authors.lastname: Belić
authors.affiliation: Department of Experimental Medical Science, Integrative Neurophysiology and Neurotechnology, Neuronano Research Center, Lund University Lund, Sweden.
authors.forename: Pär
authors.initials: P
authors.lastname: Halje
authors.affiliation: Department of Experimental Medical Science, Integrative Neurophysiology and Neurotechnology, Neuronano Research Center, Lund University Lund, Sweden.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Richter
authors.affiliation: Department of Experimental Medical Science, Integrative Neurophysiology and Neurotechnology, Neuronano Research Center, Lund University Lund, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Petersson
authors.affiliation: Science for Life Laboratory, School of Computer Science and Communication, KTH Royal Institute of TechnologyStockholm, Sweden; Department of Neuroscience, Karolinska InstituteStockholm, Sweden.
authors.forename: Jeanette
authors.initials: J
authors.lastname: Hellgren Kotaleski
keywords: Parkinson's disease; cortico-striatal circuits; cross-frequency coupling; effective connectivity; levodopa-induced dyskinesia