Research Paper Volume 13, Issue 5 pp 7314—7329

Levodopa affects spike and local field synchronisation in the pedunculopontine nucleus of a rat model of Parkinson’s disease

Hao Zhang1, *, , Jinlu Xie2, *, , Yaqiong Li1, *, , Huimin Liu3, , Chuanguo Liu1, , Dongfang Kan1, , Xiwen Geng1, , Sheng Wei1, ,

  • 1 Experimental Centre, Shandong University of Traditional Chinese Medicine, Ji’nan 250355, Shandong, China
  • 2 Key Laboratory of Vector Biology and Pathogen Control of Zhejiang, School of Medicine, Huzhou University, Huzhou Central Hospital, Huzhou 313000, Zhejiang, China
  • 3 Department of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Ji’nan 250355, Shandong, China
* Equal contribution

Received: November 4, 2020       Accepted: January 4, 2021       Published: February 26, 2021
How to Cite

Copyright: © 2021 Zhang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


The pedunculopontine nucleus (PPN) undergoes significant anatomic and electrophysiological alterations in Parkinson’s disease (PD), severely impacting locomotion. However, the effect of 6-hydroxydopamine (6-OHDA) lesion and levodopa (L-DOPA) therapy on the relationships between spike activities and local field potential (LFP) within the PPN is not well-understood. Synchronisation between the spike activity of individual neurones and LFP of neuronal ensembles is a crucial problem in the pathogenesis of PD. In this study, LFP signals and spikes in the PPN of rats in control, lesioned, and L-DOPA groups were recorded synchronously with a multi-unit electrical signal acquisition system and analysed for their coherence value, spike-field coherence, and phase-lock relationship. The spike-LFP relationship in the PPN was markedly increased in specific frequency bands because of the 6-OHDA lesion but differed depending on the animal locomotion state and neuronal type. L-DOPA had a limited therapeutic effect on the 6-OHDA-induced increase in the coherence value. Our study demonstrates that the PPN spike-LFP relationship is involved in the pathogenesis of PD and is critical for the effects of L-DOPA, providing a basis for the clinical treatment of refractory PD symptoms.


APO: apomorphine; DBS: deep brain stimulation; ISI: inter-spike intervals; L-DOPA: levodopa; LFP: local field potential; 6-OHDA: 6-hydroxydopamine; PCA: principal component analysis; PD: Parkinson’s disease; PPN: pedunculopontine nucleus; SFC: spike-field coherence; STP: spike-triggered power; TH: tyrosine hydroxylase.