Real-time Monitoring Unveils Three Distinct Neuronal Response Patterns to SAW Ultrasound via L-type Calcium Channels

Ultrasound neuromodulation shows promise for treating neurological disorders, but the underlying mechanisms remain unclear. Here, we developed an integrated surface acoustic wave (SAW) ultrasound chip enabling simultaneous electrophysiological recording and Ca²⁺ imaging of cultured hippocampal neurons to investigate neuronal excitability and synaptic transmission during ultrasound stimulation. This study revealed, for the first time, three distinct neuronal response patterns induced by SAW ultrasound: an immediate response showing rapid activation, a delayed response exhibiting facilitation after several minutes, and a non-response maintaining baseline activity. Ultrasound stimulation increased action potential firing, enhanced excitatory postsynaptic currents, and elevated intracellular Ca²⁺ levels. These effects were dependent on extracellular Ca²⁺ influx and primarily dominated by L-type Ca²⁺ channels. Our findings suggest that individual neurons exhibit heterogeneous responses to SAW ultrasound stimulation based on their intracellular Ca²⁺ levels and L-type Ca²⁺ channel activity. This integrated approach provides new insights into the cellular mechanisms of ultrasound neuromodulation while highlighting the potential of SAW technology for precise, cell-type-specific neural control.