library_construction_protocol: Coronal brain slices including the drosal raphe neuclei (250 μm thick) were prepared. Patch electrodes with tips of 5-10 μm diameters were pulled and advanced towards the YFP-positive 5-HT neurons in the acute brain slice. Positive pressure was applied until the tips were next to the cells. Slight negative pressure was then applied until the entire somatic compartment was aspirated into the recording pipette. Immediately, the samples (less than 0.5 μl) were ejected into lysis buffer (4.5μl) and reverse transcription was performed using a SMARTer Ultra Low RNA Kit (Clontech, Japan) RNA libraries were prepared for sequencing using standard Illumina protocols