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Threshold for Tonic Motor Effects from Random Waveform in a Rat Experimental Model of Frontal Cortex Stimulation
James W Leiphart1,2, Zhixing Ye3, Michaela Lee4
1Department of Neurosciences, Inova Health System, Falls Church, Virginia, USA, james.leiphart@gmail.com.
Background:
Brain stimulation is utilized to treat a variety of neurological disorders. Clinical brain stimulation technologies currently utilize charge-balanced pulse stimulation. The brain may better respond to other stimulation waveforms. This study was designed to evaluate the motor threshold of the brain to stimulation with various waveforms.
Methods:
Three stimulation waveforms were utilized on rats with surgically implanted brain electrodes: pulses, square waves, and random waveform. The peak-to-peak stimulation voltage was increased in a step-wise manner until motor signs were elicited.
Results:
The random waveform had the highest motor threshold with brain stimulation compared to the other waveforms. Random waveform stimulation reached maximum voltage without motor side effects while stimulating through both 1 and 8 electrodes. In contrast, the stimulation thresholds for motor side effects of the other two waveforms were on average less than half of the maximum voltage and lower for stimulation through 8 electrodes than stimulation through 1 electrode (p < 0.0005).
Conclusion:
The random waveform was better tolerated than the other waveforms and may allow for the use of higher stimulation voltage without side effects.
