Journal: EMBO Molecular Medicine

Article Title: Utility of red‐light ultrafast optogenetic stimulation of the auditory pathway

doi: 10.15252/emmm.202013391

Figure Lengend Snippet: A Exemplary oABRs driven with varying radiant flux (1000 × 1 ms at 10 Hz, colors code the radiant flux in mW) of mice injected with AAV‐PHP.B‐vf‐Chrimson (left) or AAV‐PHP.B‐vf‐Chrimson‐ES/TS (right). First positive (P 1 ) and first negative (N 1 ) peaks are indicated by black dots on the waveform triggered upon 41.7 mW radiant flux (the initial negative deflection results from filtering). Vertical scale bar: 1 µV. B Exemplary oABRs driven with varying stimulation rate (1 ms for data points ≤ 500 Hz and 0.5 ms above 500 Hz at 41.7 mW (highest radiant flux), colors code the stimulation rate) of the same animals from (A). Stimuli applied at a rate of 200 Hz and the corresponding P 1 ‐N 1 pairs are indicated by yellow shaded area and black dots, respectively. Vertical scale bar: 1 µV. C oABRs driven with varying light pulse duration (10 Hz at 41.7 mW (highest radiant flux)), colors code the pulse duration) of the same animals from (A). Exemplary pulse duration of 1 ms and corresponding P 1 ‐N 1 pair are indicated by yellow shaded area and black dots. Vertical scale bar: 1 µV. D–I Quantification of P 1 ‐N 1 amplitudes (mean ± SEM) and P 1 latencies (mean ± SEM) as a function of radiant flux (D, E, vf‐Chrimson: N = 13 mice, vf‐Chrimson‐ES/TS: N = 9 mice), stimulation rate (F, G, vf‐Chrimson: N = 13 mice, vf‐Chrimson‐ES/TS: N = 8 mice), and pulse duration (H, I, vf‐Chrimson: N = 10 mice, vf‐Chrimson‐ES/TS: N = 9 mice). The average P 1 ‐N 1 amplitude of f‐Chrimson (green in F and G) is replotted from Mager et al, . Inset in (D), quantification of the oABR threshold. Inset in (E), quantification of the shortest P1 latencies elicited among any radiant flux (****, P ‐value < 10 −4 , Mann–Whitney U ‐test). Inset in (H), quantification of the optimal pulse duration required to elicit the maximum P 1 ‐N 1 amplitude. Boxes show 25th percentile, median, 75th percentile, the black dot the mean, and whiskers maximum and minimum. Source data are available online for this figure.

Article Snippet: So far estimates of this so‐called output dynamic range of the activation of the auditory pathway were based either on oABR amplitude (approximately 10–16 dB [mW], Mager et al, ; Wrobel et al, ) or multi‐unit firing rate in the inferior colliculus (approximately 11 dB [mW], Dieter et al, ).

Techniques: Injection, MANN-WHITNEY