Sajjad Moazeni, Eric H. Pollmann, Vivek Boominathan, Filipe A. Cardoso, Jacob T. Robinson, Ashok Veeraraghavan and Kenneth L. Shepard, “A Mechanically Flexible, Implantable Neural Interface for Computational Imaging and Optogenetic Stimulation over 5.4 x 5.4mm2 FoV“, IEEE Transactions on Biomedical Circuits and Systems (Early Access)

Emerging optical functional imaging and optogenetics are among the most promising approaches in neuroscience to study neuronal circuits. Combining both methods into a single implantable device enables all-optical neural interrogation with immediate applications in freely-behaving animal studies. In this paper, we demonstrate such a device capable of optical neural recording and stimulation over large cortical areas. This implantable surface device exploits lens-less computational imaging and a novel packaging scheme to achieve an ultra-thin (250μm-thick), mechanically flexible form factor. The core of this device is a custom-designed CMOS integrated circuit containing a 160 x 160 array of time-gated single-photon avalanche photodiodes (SPAD) for low-light intensity imaging and an interspersed array of dual-color (blue and green) flip-chip bonded micro-LED (μLED) as light sources. We achieved 60μm lateral imaging resolution and 0.2mm3 volumetric precision for optogenetics over a 5.4 x 5.4mm2 field of view (FoV). The device achieves a 125-fps frame-rate and consumes 40mW of total power.