Brain thermal response to low intensity focused ultrasound at the action potential level and neuron response to various stimulus.

Ultrasound neuromodulation is a non-invasive technique that modulates neuronal activity through energy transfer or mechanical effects. Understanding how focused ultrasound (FUS) influences neuronal states is essential for advancing therapeutic applications. Neurophysiology relationship to ultrasound is far from understood. Neuron Action Potential (AP) provides insight into the transition between resting and active states, but detecting thermal changes during FUS exposure remains a challenge. This study addressed this gap by developing a simulation to accurately detect thermal variations induced by low-intensity focused ultrasound (LIFU) exposure. The neuron model was analyzed to determine the voltage required for state transitions, with various simulation files generated at different timing intervals (1, 5, and 10 s) and duty cycles of 10 % and 90 %. Brain thermal elevation was recorded at an input of 7 kPa and an intensity of 0.0017 W/cm², reaching a maximum of 37.009403 °C with a 90 % duty cycle at 10 s. Temperature elevation was observed even at the low-intensity action potential level, suggesting that thermal effects can occur with minimal energy input. Mechanical factors such as displacement or force may contribute to neuronal depolarization. These findings indicate that both thermal and mechanical factors influence ultrasound-induced neuromodulation, with implications for optimizing non-invasive neuromodulation techniques.