Decreased chemosensitive responses of serotonergic DRN neurons in Htr1a^RO mice in the absence of synaptic blockade.

<p><i>A, B,</i> Representative recordings performed in normal phenylephrine-supplemented ACSF showing time-courses of serotonergic neuron firing in response to bath application of 9% and 3% CO₂ in slices from control (<i>A</i>) and Htr1a^RO (<i>B</i>) mice. Lines show firing rate calculated over 10 s bins. Traces illustrate recorded action currents for each experiment. Arrows indicate the application of the Htr1a agonist R-8-OH-DPAT (30 nM) that silenced recorded neurons confirming that they are serotonergic. <i>C,</i> Bar graph of baseline firing rate in control and Htr1a^RO mice. <i>D,</i> Summary bar graph comparing the effects of 9% and 3% CO₂ in two groups. In Htr1a^RO mice the response to 9% CO₂ was significantly reduced when compared to control littermates. ** <i>p</i><0.01 (Mann-Whitney test). Number of recorded neurons is indicated in parentheses.</p

In the absence of α₁-adrenoceptor stimulation, 9% CO₂ does not change firing rate of spontaneously active serotonergic neurons in control mice.

<p><i>A,</i> Time-course of a representative experiment. Phenylephrine was omitted from ACSF containing synaptic blockers. Inset shows the recorded action current. <i>B,</i> Distribution of responses to 9% CO₂ for all recorded neurons.</p

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

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

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

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

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

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

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

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