Abnormal Spontaneous Neuronal Discharge and Local Field Potential both in Cortex and Striatum of a Non- human Primate of Parkinson's Disease using Implantable Microelectrode Arrays.

Abstract

Parkinson's disease (PD) is a neurodegenerative disease with the loss of dopaminergic neurons in substantia nigra. This study described abnormal spontaneous neuronal information both in cortex and striatum of a non-human primate of PD using implantable microelectrode arrays. In cortex of PD monkey, Neurons discharged from single-spike mode to burst-firing mode compared to normal monkey; Mean amplitude was $197 \mu \mathrm{V}$ that was twice of mean amplitude of normal monkey, and mean firing rate was 82Hz; burst-firing activity showed distinctive, stereotypic periods of oscillatory lasted for $20 \pm 5\mathrm{s}$ occurring ever 30-40 seconds, which was consistent with local field potential (LFP) oscillating at 4.79Hz related to PD tremor; neuronal discharge were approximately synchronous from four channels, that were consistent with local field potential fluctuating greatly with a correlation coefficient of 0.99997, and the main frequency of local field potential had a good respond to firing rate of spike with a correlation coefficient of 0.9891. In striatum of PD monkey, two types of neurons were detected with mean amplitude of $102 \mu \mathrm{V}$ and $296 \mu \mathrm{V}$ respectively; the mean firing rate was 62 Hz significantly higher than that in normal monkey; as for one representative type of neurons, with respect to local field potential oscillating at a period in cortex, local field potential continuously oscillated in striatum at low frequency at the range of 4-7Hz which was constituent with neuronal burst firing rate, while single neuron discharged at the range of 10-32Hz, almost at beta frequencies. Abnormal neural information detection by microelectrode arrays with ifferent signals in different position will play an important role in target location in brain of PD patients, especially for treatment.