The inhibition of sensory responsivity is considered a core serotonin function, yet this hypothesis lacks direct support due to methodological obstacles. We adapted an optogenetic approach to induce acute, robust and specific firing of dorsal raphe serotonergic neurons. In vitro, the responsiveness of individual dorsal raphe serotonergic neurons to trains of light pulses varied with frequency and intensity as well as between cells, and the photostimulation protocol was therefore adjusted to maximize their overall output rate. In vivo, the photoactivation of dorsal raphe serotonergic neurons gave rise to a prominent light-evoked field response that displayed some sensitivity to a 5-HT1A agonist, consistent with autoreceptor inhibition of raphe neurons. In behaving mice, the photostimulation of dorsal raphe serotonergic neurons produced a rapid and reversible decrease in the animals’ responses to plantar stimulation, providing a new level of evidence that serotonin gates sensory-driven responses.
Spike probability vs irradiance
Experiment: photosensitivity of ChR2-EYFP-positive dorsal raphe neurons assessed in acute slices (see the Supplementary Information section for a detailed description of the protocol). The file contains the average spike probabilities of 21 neurons for different irradiance values (Fig. 1H and I in the paper). Columns with names ending with "_SpikeProb" contain the spike probabilities. Columns with names ending with "_Irradiance" contain irradiance values in mW/mm2. E.g., for cell 5, the spike probability curve can be obtained by plotting "Cell5_SpikeProb" versus "Cell5_Irradiance".
Spike_probability_vs_irradiance.csv
Spike times at twice the photostimulation threshold
Experiment: Spiking reliability of ChR2-EYFP-positive dorsal raphe neurons in response to trains of light pulses at different frequencies, using an irradiance = twice the photostimulation threshold. This zip file contains a list of 30 .csv file. Each .csv file contains a table of spike times (time of occurrence of spikes, in seconds) measured for one neuron in response to trains of light pulses at different frequencies (1, 2, 5, 10, 20 and 50 Hz). Each column represents one frequency (the frequency is indicated in the first row). Columns are filled with NAs at the end so that they have the same length. These data were used to generate the plots in Fig. 1L, Supp. Fig. S1B and Fig. S1D1 to D3.
Spike_times_2X_photostimulation_threshold.zip
Spike times at maximal irradiance
Experiment: Spiking reliability of ChR2-EYFP-positive dorsal raphe neurons in response to trains of light pulses at different frequencies, using an irradiance = ~5 mW/mm2. This zip file contains a list of 14 .csv file. Each .csv file contains a table of spike times (time of occurrence of spikes, in seconds) measured for one neuron in response to trains of light pulses at different frequencies (1, 2, 5, 10, 20 and 50 Hz). Each column represents one frequency (the frequency is indicated in the first row). Columns are filled with NAs at the end so that they have the same length. These data were used to generate the plots in Fig. 1L, Supp. Fig. S1B and Fig. S1E1 to E3.
Spike_times_max_irradiance.zip
Number of spikes vs pulse duration
Experiment: assessing the number of spikes evoked in ChR2-EYFP-positive dorsal raphe neurons, for light pulses of various duration. This .csv contains the average number of spikes obtained in individual neurons in response to light pulses of different durations (0.1 to 1000 ms; n = 17 neurons). Each row corresponds to one neuron. Each column corresponds to one pulse duration (the duration is indicated in the first row). These data were used to generated Fig. 1J.
Light transmission in DRN
This .zip file contains pictures obtained by shining light through an optical fiber over the dorsal aspect of the dorsal raphe nucleus (in freshly dissected brain tissue, see the paper for a detailed description of the procedure). The archive contains pictures from 3 different brains. For each brain, the same field of view was imaged using brightfield illumination (file names ending with "_TL") in order to show the contours of the DRN, and under illumination through the optical fiber (file names ending with "_OF_ILLUMINATION"). The format is 12 bits encoding. These pictures were used to generate Fig. 2B, C and D.
Light_transmission_in_DRN.zip
Linear pixel intensity profiles
Experiment: light propagation in the dorsal raphe nucleus. This .csv file contains normalized pixel intensity profiles for 3 brains, measured along the optical fiber axis (see paper for a detailed description of the procedure). These data are plotted in Fig. 1D.
Linear_profiles.csv
Combined fluorescence and OLFP mapping
Experiment: combined fluorescence and OLFP (= optically-evoked field potential) mapping in vivo. This file contains the following values for 8 different animals: average fluorescence intensity in the first millimeter of tissue, maximal fluorescence intensity, position of point of maximal fluorescence, full width at half maximum of fluorescence intensity profile, maximal value of OLFP amplitude, position of point with largest OLFP and full width at half maximum of OLFP amplitude profile (see README.txt). These data were used in Fig. 2F.
Effet of 8-OHDPAT on OLFP
Experiment: sensitivity of the optically-evoked field potential (OLFP) to a 5-HT1A receptor agonist (8-OH-DPAT). This file contains the average OLFP amplitude and peak latency before and after the injection of 8-OH-DPAT (see the paper for a detailed description of the protocol) for 10 mice. These data were used in Fig. 2H.
Effet_of_8-OHDPAT_on_OLFP.csv
Fits OLFP amplitude and latency vs power
This file contains the fit parameters of the OLFP amplitude vs power and OLFP latency vs power curves for 9 mice. See README.txt for a detailed description of the fit parameters.
Fits_OLFP_amplitude_and_latency_vs_power.csv
OLFP amplitude and latency vs frequency
The .zip file contains the values of the OLFP amplitude and latency for different photostimulation frequencies in 7 mice (see the paper for a detailed description of the protocol). The files ending with "_Freq" contain the list of frequencies (in Hz). The files ending with "_Peak_vs_Freq" contain the values of the OLFP amplitude (in Volts). The files ending with "_Lat_vs_Freq" contain the values of the OLFP latency (in seconds). These data were used in Fig. 2J.
OLFP_amplitude_and_latency_vs_frequency.zip
OLFP recovery
The .zip file contains the values for the OLFP amplitude recovery experiment (Fig. 2K; see the paper and the supporting information for a detailed description of the protocol). The files ending with "_stim_Y" contain the normalized OLFP amplitude values in the stimulation period (in blue on Fig. 2K). The files ending with "_recov_Y" contain the normalized OLFP amplitude values in the recovery period (in green on Fig. 2K). The file "Stim_X.txt" contains the time points for the stimulation period. The file "Recov_X.txt" contains the time points for the recovery period.
OLFP_recovery.zip
Von Frey experiment
This .csv file contains the scored data for the Von Frey experiment (Fig. 3). See the paper and supporting information for a detailed description of the experiment. A description of the data contained in the .csv is available in the README.txt file.
Von_Frey_experiment.csv
