Exposure to social stress and dysregulated serotonergic neurotransmission have both been implicated in the etiology of psychiatric disorders. This research explored whether a serotonergic input from the dorsal raphe (DR) to the ventral tegmental area (VTA) influences vulnerability to social stress. A distinct serotonergic sub-population in the DR projecting to the VTA (5-HTDR→VTA neurons) was identified, and its activity was found to be decreased by susceptibility to social stress. Bidirectional manipulation of 5-HTDR→VTA neurons modulated susceptibility to social stress, suggesting these neurons are an essential factor in determining individual stress susceptibility and highlighting their potential as therapeutic targets for stress-related disorders.
