A hierarchical neural stimulation model for pain relief by variation of coil design parameters

Neural stimulation represents a powerful technique for neural disorder treatment. This paper deals with optimization of coil design parameters to be used during stimulation for modulation of neuronal firing to achieve pain relief. Pain mechanism is briefly introduced and a hierarchical stimulation model from coil stimulation to neuronal firing is proposed. Electromagnetic field distribution for circular, figure of 8 and Magnetic resonance coupling figure of 8 coils are analyzed with respect to the variation of stimulation parameters such as distance between coils, stimulation frequency, number of turns and radius of coils. MRC figure of 8 coils were responsible for inducing the maximum Electric field for same amount of driving current in coils. Variation of membrane potential, ion channel conductance and neuronal firing frequency in a pyramidal neuronal model due to magnetic and acoustic stimulation are studied. The frequency of neuronal firing for cortical neurons is higher during pain state, compared to no pain state. Lowest neuronal firing frequency 18 Hz was found for MRC figure of 8 coils, compared to 30 Hz for circular coils. Therefore, MRC figure of 8 coils are most effective for modulation of neuronal firing, thereby achieving pain relief in comparison to other coils considered in this study.