Biology subjects

Stratmann, A.

Publications and source records attributed to Stratmann, A..

4 recordsLinked to original sources

bioRxiv2026

Artificial Reactivation of a Cocaine-Associated Engram in the Dorsal Dentate Gyrus Attenuates Cocaine Prime-Induced Reinstatement of Drug-Seeking

Relapse-prevention strategies aimed at reducing relapse following abstinence, primarily focus on reducing cravings that lead to drug-seeking triggered by stress, drug-related cues, or re-exposure to the drug. Because addictive drugs form persistent associative contextual memories, we investigated how reactivation of cocaine-related hippocampal memories influences subsequent drug-seeking. Here, we tagged dorsal dentate gyrus (dDG) memory ensembles involved in encoding either a first or fourth cocaine exposure (15mg/kg, i.p) in male and female c57BL/6 mice using a TetTag approach. Mice underwent cocaine conditioned place preference (CPP), extinction, and reinstatement. We assessed whether optical reactivation of tagged cocaine-related ensembles could substitute for a cocaine priming injection to reinstate CPP, whether reactivation altered cocaine-induced reinstatement, and if these effects differed depending on stage of drug exposure. We also compared these effects to reactivation of saline-associated ensembles. Cocaine produced robust locomotor activation during conditioning, and sensitization developed across repeated drug exposures. Reactivation of a cocaine-related engram alone did not reinstate CPP. However, reactivation of the first cocaine exposure engram attenuated cocaine-induced reinstatement. In contrast, reactivation of the fourth exposure engram did not confer this protective effect. Interestingly, reactivation of saline-associated ensembles also reduced cocaine-induced reinstatement specifically in females, suggesting dDG ensemble reactivation may modulate relapse-related behavior through interference or neuromodulatory disruption of cocaine-associated representations, consistent with our prior work. These findings raise the possibility that early contextual experiences form competing or destabilizing representations that interfere with later cocaine-seeking when reactivated. Females also displayed greater sensitivity to locomotor-inducing effects of cocaine memory reactivation, although this was dissociated from CPP. Together, these findings show that cocaine memories are distinct across drug experience and selective reactivation of dDG engrams can differentially influence drug-seeking.

animal behavior and cognition↗

bioRxiv2024

MooViE - Engine for single-view visual analysis of multivariate data

SummaryUnderstanding input-output relationships within multivariate datasets is an ubiquitous task in the life and data sciences. For this, visual analysis is indispensable for providing expressive summaries and preparing decision-making. We present the visual analysis approach and software MooViE, which is designed to strike the balance between being tailored to the specific data semantic and while being broadly applicable. MooViE supports the data exploration process for extracting important information from the data and captures the result in a fresh single-view visualization. MooViE is implemented in C++ to facilitate fast access and effective interaction with comprehensive multivariate datasets. We showcase the engine for various application fields, relevant to the life sciences. Availability and ImplementationThe source code is available under MIT license at https://jugit.fz-juelich.de/IBG-1/ModSim/MooViE and https://github.com/JuBiotechMooViE, with detailed documentation and usage instructions (https://moovie.readthedocs.io), as well as zenodo-archived releases (https://doi.org/10.5281/zenodo.10997388). Platform independent Docker images are also available (jugit-registry.fz-juelich.de/ibg-1/modsim/moovie/moovie). ContactKatharina Noh k.noeh@fz-juelich.de

bioinformatics↗

bioRxiv2023

hopsy - a methods marketplace for convex polytope sampling in Python

SummaryEffective collaboration between developers of Bayesian inference methods and users is key to advance our quantitative understanding of biosystems. We here present hopsy, a versatile open source platform designed to provide convenient access to powerful Markov chain Monte Carlo sampling algorithms tailored to models defined on convex polytopes (CP). Based on the high-performance C++ sampling library HOPS, hopsy inherits its strengths and extends its functionalities with the accessibility of the Python programming language. A versatile plugin-mechanism enables seamless integration with domain-specific models, providing method developers with a framework for testing, benchmarking, and distributing CP samplers to approach real-world inference tasks. We showcase hopsy by solving common and newly composed domain-specific sampling problems, highlighting important design choices. By likening hopsy to a marketplace, we emphasize its role in bringing together users and developers, where users get access to state-of-the-art methods, and developers contribute their own innovative solutions for challenging domain-specific inference problems. Availability and ImplementationSources, documentation and a continuously updated list of sampling algorithms are available at https://jugit.fz-juelich.de/IBG-1/ModSim/hopsy, with Linux, Windows and MacOS binaries at https://pypi.org/project/hopsy/. Contactk.noeh@fz-juelich.de

systems biology↗

bioRxiv2021

Welfare at group and individual level: optical flow patterns of broiler chicken flocks are correlated with the behaviour of individual birds

Group level measures of welfare such as the optical flow patterns made by broiler chicken flocks have been criticized on the grounds that they give only average measures and overlook the welfare of individual animals. However, we here show that by using the skew and kurtosis in addition to the mean, optical flow patterns can be used to deliver information not just about the flock average but also about the proportion of individuals in different movement categories. We correlated flock optical flow patterns with the behaviour of a sample of 16 birds per flock in two runway tests and a water (latency-to-lie) test. In the runway tests, there was a positive correlation between the time taken to complete the runway and the skew and kurtosis of optical flow on day 28 of flock life (slow individuals came from flocks with a high skew and kurtosis). In the water test, there was a positive correlation between the length of time the birds remained standing and the mean and variance of flock optical flow (the most mobile individuals came from flocks with the highest mean). Patterns at flock level thus contain valuable information about the welfare of the individuals that compose the flock. Simple SummaryTechnology on farms potentially brings benefits of improved animal health, welfare and productivity as well as reduction in disease, waste and environmental impact. However, it also raises public concern about the welfare of individual animals, particularly when applied to large groups such as broiler (meat) chickens. We here address this issue by showing that camera technology can both provide life-long continuous monitoring of the welfare of whole flocks and also give crucial information about the individuals making up the flock. The cameras detect variation between individuals and are also sensitive to birds moving abnormally. By testing birds individually, we show that slow-moving birds tended to come from flocks that moved slowly overall and showed large variation between individuals whereas fast-moving birds were more likely to come from more active flocks that moved more uniformly. Properly used, camera technology can thus monitor the welfare of flocks continuously throughout their lives while reflecting the behaviour of individual birds.

animal behavior and cognition↗