Fig. 5: In vivo neural recording of the mouse barrel cortex using MOTEs.

a, (i) Measurement setup, in which a computer-controlled motor moves a rod to stimulate a whisker of an awake, head-fixed mouse during MOTE recording. (ii),(iii) Stereoscopic images of MOTEs implanted in the barrel cortex over 161 days. (iv) Neuron staining near a MOTE implant site 31 days after insertion. b, MOTE action potential recordings in mouse 2 after 13 days (top) and 102 days (bottom) of implantation. The overlay plots confirm the presence of action potentials, and the dot raster plots (indicating spike timing over 100 stimulation cycles) and peri-stimulus time histograms show a strong causal relationship between the whisker stimuli (grey zone) and spikes. The increase in stimulus-induced spikes on day 102 might be due to decreased inflammation over time and/or MOTE migration closer to an axon hillock. Grey windows denote the rod movements. c, LFP measurements from MOTEs in multiple mice and over multiple days. (i) Thirty sequential recordings of MOTE 1 in mouse 1 after 4 days (left), 161 days (middle) and 304 days (right) of implantation. Whisker contact timing may vary between measurements, probably causing the observed change in the time delay between the rod movement and onset of LFPs. (ii) Overlay plot and average of the 30 traces taken on day 4 (top), compared with the control case in which the stimulation rod is moving but does not touch the whisker, confirming that the LFP responses are not electrical artefacts. Control: no twitch. (iii) LFP recording, overlay and average, from the second MOTE in the same mouse (mouse 1) after 161 days of implantation; the LFP recordings became slightly weaker and noisier after 161 days, which may have been caused by electrode degradation, scar tissue formation and/or the movement of the MOTEs (~50–300 µm; measured using a three-photon microscope²⁵ (Extended Data Fig. 7)) inside the brain as the initial inflammation subsided. (iv) Overlay and average plot of the LFP recording from the MOTE in mouse 2 after 102 days of implantation; this is the same MOTE and mouse as in the action potential measurement shown in b. Same mouse and MOTE as in Fig. 4b. 0 ms denotes the beginning of the rod movement. All the LFP data (c) and action potential data (b) shown were band-passed between 10–250 Hz and 300–4,000 Hz, respectively, using a fourth-order Butterworth filter. Panel a(i) adapted with permission from ref. ⁴³, Springer Nature Limited.