Novel fractal planar electrode design for efficient neural stimulation

Area of Science:

• Biomedical Engineering
• Computational Neuroscience
• Materials Science

Background:

• Planar electrodes are crucial for epidural spinal cord and cortical stimulation.
• Stimulation efficiency is defined by activating neural tissue with minimal voltage and power.
• Current density concentrates at electrode edges, influencing activation patterns.

Purpose of the Study:

• To investigate if fractal electrode designs increase stimulation efficiency.
• To compare the voltage and power requirements of Koch snowflake electrodes against traditional designs.
• To evaluate the impact of fractal geometry on neural tissue activation.

Main Methods:

• Utilized COMSOL Multiphysics to model three iterations of Koch snowflake fractal electrodes with equal surface area to traditional square and circular designs.
• Interpolated finite element model voltages to determine nodal voltages for 100 randomly positioned axons.
• Simulated threshold voltage and power for axon activation using NEURON software.

Main Results:

• The 3rd iteration Koch snowflake electrode exhibited significantly higher current density variation than the traditional square electrode.
• This novel fractal electrode activated a greater number of axons at a lower threshold voltage compared to the square electrode.
• Fractal geometry demonstrably influenced current distribution and neural activation.

Conclusions:

• Computational models confirm that Koch snowflake fractal electrodes can improve stimulation efficiency.
• Novel electrode designs with increased fractal complexity show potential for optimized neural stimulation.
• Further research into advanced fractal geometries could yield more efficient stimulation devices.