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Marquardt, L.

Publications and source records attributed to Marquardt, L..

2 recordsLinked to original sources

Neuronal networks in the dorsal hippocampus causally regulate rescue behavior in mice

Prosocial behaviors, such as rescuing individuals in need, are crucial for social cohesion across species. While key brain regions involved in rescue behavior have been identified, the underlying neural mechanisms remain unclear. The hippocampus (HPC), known for its role in memory and spatial navigation, also contributes to emotional and social processing. However, its specific involvement in prosocial behavior is not well understood. Here, we investigate the causal role of the HPC in learning and executing rescue behavior in mice. Using chemogenetics, we show that the dorsal HPC (dHPC), but not the ventral HPC (vHPC), is essential for acquiring rescue behavior. Calcium imaging of the dHPC reveals network consolidation during successful rescues, with distinct synchronized ensembles and activity patterns linked to liberations of an individual in need. These findings establish a novel role for the dHPC in prosocial behavior, providing insights into the neural mechanisms underlying empathy-driven actions.

neuroscience↗

Group A Streptococcus strains causing meningitis without distinct invasive phenotype

Group A streptococcal (GAS, aka Streptococcus pyogenes) meningitis is a fulminant disease associated with high morbidity and mortality. To elucidate the mechanisms underlying the invasiveness of GAS in meningitis, we compared GAS isolates derived from five cases of meningitis, to otitis and colonizing isolates. We did not observe differences in adherence to and invasion of human brain microvascular endothelial cells, virulence factors activity or barrier disruption. Whole genome sequencing did not reveal particular invasiveness traits. Most patients previously suffered from otitis media suggesting that meningitis likely resulted from a continuous spread of the infection rather than being attributable to changes in pathogens virulence.

microbiology↗