Biology subjects

Sterley, T.-L.

Publications and source records attributed to Sterley, T.-L..

3 recordsLinked to original sources

bioRxiv2026

A transient hypothalamic CRH signal coordinates social investigation in mice

Successful navigation of the social environment depends on the ability to rapidly evaluate conspecifics and adjust behaviour accordingly. Encounters with unfamiliar individuals are particularly challenging because they introduce uncertainty about how the interactions may unfold. Such social encounters can lead to beneficial or detrimental outcomes, making rapid assessment critical for survival; yet the neural mechanisms underlying this process remain poorly understood. Corticotropin-releasing hormone synthesizing neurons in the paraventricular nucleus of the hypothalamus (CRHPVN), traditionally viewed as the canonical endocrine controllers of the stress response, have been implicated in processing behaviourally relevant environmental and social information, including the investigation of stressed conspecifics. However, their role in rapidly evaluating conspecifics during social encounters remains unclear. Here, using fibre photometry and optogenetics during ethologically relevant social encounters, we show that CRHPVN neurons exhibit a rapid, transient increase in activity that precedes investigative behaviour. This signal scales with social context, is elevated during exposure to unfamiliar relative to familiar conspecifics, persists across novel environments, and generalizes across unfamiliar strains. In contrast, interactions with juvenile conspecifics and inanimate objects do not elicit this differential activity, indicating that CRHPVN recruitment is not driven solely by novelty. Critically, temporally specific inhibition of CRHPVN neurons during this brief activity window produces lasting changes in behaviour beyond the period of inhibition, including the reduction of appropriate social investigation, indicating that this transient activity is necessary for gating subsequent social behaviour. Together, these findings identify CRHPVN neurons as a rapid integrative node linking hypothalamic function to social evaluation.

neuroscience↗

bioRxiv2025

Hypothalamic CRH neurons gate rapid social appraisal of conspecifics

Successful navigation of the social environment requires rapid evaluation of conspecifics to distinguish safe from threatening encounters. While the corticotropin-releasing hormone neurons in the paraventricular nucleus of the hypothalamus (CRHPVN) are well known for orchestrating endocrine stress responses, their role in real-time social appraisal is unknown. Here, using fibre photometry and optogenetics during ethologically relevant social interactions, we show that CRHPVN neurons exhibit a rapid, transient increase in activity that precedes sniffing, an investigative behaviour through which mice gather social information. This transient signal scales with social context: it is heightened during interactions with unfamiliar and aggressive conspecifics and significantly reduced toward familiar partners. Inhibiting these neurons selectively diminished anogenital sniffing, demonstrating their necessity for optimal social evaluation. Strikingly, across repeated exposures to the same conspecific, behavioural investigation declined while CRHPVN activity remained robust, revealing a dissociation between neuronal and behavioural habituation. This persistence suggests that CRHPVN neurons encode stable neural representation of threat during social encounters. Together, our findings identify CRHPVN neurons as a fast, integrative node linking endocrine stress control to rapid social decision-making.

neuroscience↗

bioRxiv2021

Markerless mouse tracking for social experiments

Automated behavior quantification requires accurate tracking of animals. Simultaneous tracking of multiple animals, particularly those lacking visual identifiers, is particularly challenging. Problems of mistaken identities and lost information on key anatomical features are common in existing methods. Here we propose a markerless video-based tool to simultaneously track two socially interacting mice of the same appearance. It incorporates conventional handcrafted tracking and deep learning based techniques, which are trained on a small number of labeled images from a very basic, uncluttered experimental setup. The output consists of body masks and coordinates of the snout and tail-base for each mouse. The method was tested on a series of cross-setup videos recorded under commonly used experimental conditions including bedding in the cage and fiberoptic or headstage implants on the mice. Results obtained without any human intervention showed the effectiveness of the proposed approach, evidenced by a near elimination of identities switches and a 10% improvement in tracking accuracy over a pure deep-learning-based keypoint tracking approach trained on the same data. Finally, we demonstrated an application of this approach in studies of social behaviour of mice, by using it to quantify and compare interactions between pairs of mice in which some are anosmic, i.e. unable to smell. Our results indicated loss of olfaction impaired typical snout-directed social recognition behaviors of mice, while non-snout-directed social behaviours were enhanced. Together, these results suggest that the hybrid approach could be valuable for studying group behaviors in rodents, such as social interactions.

bioengineering↗