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

PIÑA-NOVO D; BELLUSCIO MA; MURER MG

cordoba

Conferencia; XXXIII CONGRESO ANUAL SAN 2018; 2018

Sociedad Argentina de Investigacón en Neurociencias

Prolonged treatment with LDopa in Parkinson's disease (PD) often leads to the emergence ofabnormal involuntary movements known as L Dopa induced dyskinesias (LIDs). Little is knownabout the oscillatory activity associated with LIDs, particularly in the motor cortex. On the otherhand, recent studies have shown that motor symptoms of parkinsonian state correlate with theexacerbation of oscillations in the beta range (15 35 Hz) although the mechanisms wh ichoriginate this activity remain unknown. Here we sought to identify such alterations by recordinglocal 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 of high density electrodes.We analyzed the oscillatory activity in the beta range and how the different cortical neuronalpopulations were related to this rhythm. We found that animals with lesion of nigrostriataldopaminergic system present an increase in the number of beta events, with greater duration andpower compared to sham animals. There is also a significant decrease in the firing rate prior to thebeginning of beta events and a better entrainment of neuronal activity by the LFP around t hemiddle of the events. After the L DOPA priming we found a similar but less pronounced pattern inLIDs "off" periods. Instead, during LIDs there is a generalized decrease in cortical beta activity, witha reduction in the number of events, its duration a nd power.