PT - JOURNAL ARTICLE AU - Jovana J. Belić AU - Pär Halje AU - Ulrike Richter AU - Per Petersson AU - Jeanette Hellgren Kotaleski TI - Untangling cortico-striatal connectivity and cross-frequency coupling in L-DOPA-induced dyskinesia AID - 10.1101/028027 DP - 2015 Jan 01 TA - bioRxiv PG - 028027 4099 - http://biorxiv.org/content/early/2015/10/04/028027.short 4100 - http://biorxiv.org/content/early/2015/10/04/028027.full AB - We simultaneously recorded local field potentials 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 analysed 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 healthy 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.