Novel Heat-Mitigating Chip-on-Probe for Brain Stimulation Behavior Experiments.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Microwave Engineering

Background:

• High temperatures from stimulus chips (40-60°C) during microwave brain stimulation can cause unintended thermal effects, particularly detrimental for repeated stimulation protocols.
• Existing chip-on-probe designs face challenges in managing heat dissipation, potentially compromising stimulation accuracy and biological safety.

Discussion:

• A novel topology vertically separates the stimulus chip and brain-inserted probe, minimizing heat transfer to neural tissue while reducing radio frequency (RF) transmission loss.
• An auxiliary board with a lightweight heat sink was designed for small animal behavioral experiments, optimizing cooling without impacting animal movement.
• Simulations indicate a potential temperature reduction exceeding 13°C with proper heat sink integration, crucial for maintaining stable brain tissue temperatures.

Key Insights:

• Fabrication using 0.28 μm SOI CMOS and RT6010 PCB demonstrates a significant temperature reduction of 49.8°C, with the brain-contacting area reaching 31.1°C at 11 dBm maximum output power.
• The proposed design effectively suppresses heat transfer to the brain, achieving a low RF transmission loss of 1.2 dB.
• This advancement offers a safer and more effective method for modulated microwave brain stimulation.

Outlook:

• Further optimization of heat sink design and transition structures could enhance cooling efficiency and minimize RF loss.
• Validation in more complex biological models and long-term studies will be essential to fully assess the therapeutic potential.
• This technology holds promise for advancing research and clinical applications in neuromodulation and brain-computer interfaces.