A lightweight discrete biphasic current stimulator for rodent deep brain stimulation

This paper presents a miniaturized discrete system for long-term biphasic deep brain stimulation (DBS) with independently programmable anodic and cathodic currents and pulse widths, frequency, pulse order and interpulse interval. It features a single current source and an H-bridge for setting current direction. The single source allows good charge balance, limiting DC current to under 50 nA which is further reduced to below 1 nA by electrode shorting. Voltage compliance is limited to 12 V. The device along with battery power supply weighs 2.3 g. The system is highly customizable, permitting tradeoff between voltage compliance and the range, resolution and accuracy of currents and between power consumption and temporal resolution with minimal hardware modification. Based on average current consumption and nominal battery capacity, the stimulator can provide 300 μA, 130 Hz, 100 μs symmetric biphasic stimulation with an 11.5 V compliance for 14 days. Design details, characterization measurements and experimental data comparing the stimulator to a benchtop device in an anesthetized rat are presented.