The Diagonal Band of Broca Regulates Olfactory-mediated Social Behaviors: A Study Using USVs As Unbiased, Ethological Markers For Social Interactionshttps://doi.org/10.60507/FK2/WB6DOIMohammadi, AliFuhrmann, FalkoTillmann, Jens F.Fuhrmann, MartinSchwarz, Martin K.bonndata2025-08-142025-08-28T11:36:40ZThe Horizontal Diagonal Band of Broca (HDB) modulates olfactory information processing by recruiting olfactory bulb (OB) interneurons to shape excitatory OB output. Here, we show that OB is strongly and differentially innervated by HDB projections. Light-induced silencing of HDB afferents in the OB via OPN3 affected olfactory-mediated social habituation and discrimination behaviors, as shown by manual annotation of investigative behavior. Additionally, we established ultrasonic vocalizations (USVs) as an unbiased, reliable, and ethologically relevant biomarker for quantifying investigative social behavior. To this end, we employed "DeepFisFis," an AI-based solution, developed in our lab for detection of mouse USVs. Collectively, our studies demonstrate that USVs serve as an effective biomarker for investigative social behavior. Furthermore, our results highlight the HDB as a crucial top-down relay in the modulation of olfactory-mediated social behaviors.Medicine, Health and Life SciencesSchwarz, I. et al. The diagonal band of Broca regulates olfactory-mediated behaviours by modulating odor-evoked responses within the olfactory bulb. bioRxiv 2020.11.07.372649 (2020). https://doi.org/10.1101/2020.11.07.372649, doi, 10.1101/2020.11.07.372649, https://doi.org/10.1101/2020.11.07.372642025-08-14Mohammadi, Ali2025-08-13CC BY 4.0