Supplementary Figure 5: Electrophysiological recordings and optogenetic stimulation using multifunctional fibers.

(a-f) Acute electrophysiological recording and optogenetic stimulation in the mPFC of transgenic Thy::ChR2-YFP mice. (a-c) Simultaneous optogenetic stimulation (wavelength λ=473 nm, power density 4.3 mW/mm², 5 ms pulse width, 10 Hz, 1 s stimulation duration, blue markers indicate laser onset) and electrophysiological recording using a multifunctional fiber-probe. (a) Recorded neural activity, (b) raster plot of the detected evoked potentials, and (c) peristimulus time histogram (PSTH) over 20 stimulation trials confirm reproducibility of the response. (d-f) Simultaneous optogenetic stimulation at 100 Hz (other parameters identical to those in (a-c)) and electrophysiological recording with a multifunctional fiber probe. (d) Decaying and uncorrelated response to 100 Hz optical stimulation is consistent with ChR2 activation dynamics³. (e) Raster plot and (f) PSTH over 20 stimulation trials confirm reproducibility of the response. (g-l) Electrophysiological recording and optogenetic stimulation in the mPFC of wild type mice 2 weeks following transfection with AAV5-CaMKIIα::ChR2-eYFP through the multifunctional fiber probe. (a, d) Electrophysiological recording during optogenetic stimulation (λ=473 nm, power density 6.4 mW/mm², 5 ms pulse width, 10 Hz and 100 Hz (d), 1 s stimulation duration, blue markers indicate laser onset) in the mPFC. (b, e) Raster plots corresponding to 40 trials of recordings in (a, d). (c, f) PSTH over 40 stimulation trials confirms reproducibility of the evoked response. Consistent with ChR2 dynamics optically evoked neural activity is correlated to laser pulses at 10 Hz, but has a decaying and uncorrelated dynamics for 100 Hz stimulation.

3. Cardin, J. a et al. Targeted optogenetic stimulation and recording of neurons in vivo using cell-type-specific expression of Channelrhodopsin-2. Nat. Protoc. 5, 247–254 (2010).