In Vivo Dual-Channel Widefield GCaMP Imaging using Transparent Ultrasound Transducer

Widefield GCaMP imaging has become an essential tool in neuroscience, enabling real-time visualization of neuronal activity, particularly in ultrasound neuromodulation studies. However, traditional ultrasound transducers obstruct the light path, thereby complicating the alignment of the optical and acoustic paths. This study introduces a transparent ultrasound transducer (TUT) fabricated from lithium niobate, specifically designed to facilitate the alignment of the optical and acoustic paths. Indium tin oxide (ITO) is used as the transparent electrode of the TUT, providing transmittance higher than 70% at wavelengths critical for GCaMP imaging. This system supports simultaneous ultrasound stimulation and imaging without optical interference, effectively accommodating the needs of dual-channel widefield GCaMP imaging. By alternating between blue and violet light for stimulation, our system allows for the distinction between neural and non-neural activity.