Characterization of beta oscillation in the primary motor cortex after nigrostriatal degeneration and during L-DOPA-induced dyskinesias in a rodent model of Parkinson's disease

DANIELA PIÑA-NOVO; MARIANO BELLUSCIO; GUSTAVO MURER

Congreso; XXXIII Congreso Anual Sociedad Argentina de Investigación en Neurociencias 2018; 2018

Prolonged treatment with L-Dopa in Parkinson´s disease (PD) oftenleads to the emergence of abnormal involuntary movements known asL-Dopa-induced dyskinesias (LIDs). Little is known about theoscillatory activity associated with LIDs, particularly in the motorcortex. On the other hand, recent studies have shown that motorsymptoms of parkinsonian state correlate with the exacerbation ofoscillations in the beta range (15-35 Hz) although the mechanismswhich originate this activity remain unknown. Here we sought toidentify such alterations by recording local field potentials (LFP)and single unit activity in primary motor cortex of hemiparkinsonianmice before and after an L-DOPA treatment to induce LIDs, by means ofhigh density electrodes. We analyzed the oscillatory activity in thebeta range and how the different cortical neuronal populations wererelated to this rhythm. We found that animals with lesion ofnigrostriatal dopaminergic system present an increase in the numberof beta events, with greater duration and power compared to shamanimals. There is also a significant decrease in the firing rateprior to the beginning of beta events and a better entrainment ofneuronal activity by the LFP around the middle of the events. Afterthe L-DOPA priming we found a similar but less pronounced pattern inLIDs "off" periods. Instead, during LIDs there is ageneralized decrease in cortical beta activity, with a reduction inthe number of events, its duration and powerp { margin-bottom: 0.1in; line-height: 115%; }