Fig. 4: Fully implantable cIGT-based amplifier for acquisition of neural activity over the course of brain development.

A Schematic of the fully implantable cIGT-based probe with axis breaks showing the electrical contacts for recording (top), the cIGT amplifier (middle), and the anchor hole (bottom). B Optical micrograph of a cIGT-based front-end amplifier (top; scale bar, 80 µm) located at the tip of the implant (middle; scale bar, 1 mm). Optical micrograph of the trocar-guided section of the device with Au-coated strip to indicate location for detachment (bottom; W, L = 20, 2 µm; scale bar, 100 µm). C Post-surgical image of implanted pup (P9) with red circle highlighting the closed scalp incision. Dashed black line indicates subcutaneous location of the device interconnects, attaching to conformable contacts externalized for recording (scale bar, 3 mm). D Image of pup implanted with cIGT-based front-end amplifier (implantation site indicated by dashed red line) surrounded by littermates in a naturalistic setting (scale bar, 10 mm). Inset shows the same mouse pup at P12 after having acquired ambulation as a natural developmental milestone (scale bar, 10 mm). E Comparison of LFP time traces (white) and their corresponding time-frequency spectrogram from mouse pup at age P14 that was implanted at P9. The traces and the heat map are scaled based on noise-level (scale bar, 300 µV). F Comparison of cross-frequency coupling of data acquired by chronically implanted cIGT vs. conducting polymer electrode. CIGT data reveals coupling between the spindle band and gamma band activity that is obscured in the conducting polymer electrode data.