Figure 4.

Electrophysiology recording from the surface-modified CNF-CPE electrodes, and its comparison with that from the unmodified electrodes. (a) A photograph of a mouse with the small CNF-CPE electrode implanted for 24 days. (b) A representative trace of spiking activities acquired from the surface-modified electrode 24 days post-implantation. (c) Two distinct clusters were isolated from the recorded signal via PCA. (d) Representative recorded electrophysiological signal following 28 weeks of implantation. The top trace shows the unfiltered signal, the middle trace shows bandpass-filtered (0.3 – 300 Hz) LFP, and the bottom trace represents the bandpass-filtered (0.5 – 5 kHz) spiking activity. (e) Two clustered units were sorted from the recording result and the corresponding PCA, indicating the quality of these two clusters. (f) A 2.5 s of LFPs was recorded from CNF-CPE electrodes with and without nano-optoelectrodes on day 0, showing a better recording performance with the surface-modified electrode. (g) The spectrograms of a 140-second-long LFP trace from both surface modified and unmodified electrodes, we observed relatively higher powers in each frequency bins from the CNF-CPE electrode with nano-optoelectrodes.