Neural plasticity and memory through the lens of microbiome-brain interactions
We are an interdisciplinary research group studying the microbiome-brain axis in relation to neural plasticity, learning, and memory. In our work, we integrate neuroimaging techniques, gut microbial profiling, and behavioural-cognitive assessments to track microbiome-brain interactions in humans and animal models, as well as in conditions of reduced neural plasticity (due to genetic risk for dementia, perturbed neurodevelopment, or stress).
We are based at the University of Vienna, Austria, and are affiliated with the Faculty of Psychology and the Centre for Microbiology and Environmental Systems Science (CeMESS).
Check here to meet the lovely team behind the science!
Enjoying the Vienna Christmas markets (2024). — New group picture to come in 2026!
Research Topics
Gut microbiome-brain interplay
for neural plasticity
The fact that the brain is influenced by the microorganisms that make up the gut microbiome substantially widens the scope of how we need to view neural plasticity, cognition and behaviour. Neural plasticity describes the brain’s capacity for reorganisation, and the hippocampus in particular is a brain structure key to learning and memory. A major part of our work is dedicated to understanding the microbial effects on hippocampal function, network topology, and related cognition (ERC Starting Grant “MemoryLane”).
Recent work also demonstrated that fluctuations in the constellation of specific gut microbial networks are associated with the structure and function of brain networks relevant to neural plasticity and flexible cognition (Wagner et al., 2026 — new preprint to be posted asap!). Moreover, we are currently assessing neurotransmitter production in synthetic microbial communities in vitro, and their impact in vivo using a novel line of animal research (FWF Cluster of Excellence “Microbiomes drive planetary health”).
Profiles of altered neural plasticity
The hippocampus and adjacent medial temporal lobe structures are critically implicated in ageing and dementia. Exciting discoveries suggest that gut microbial signalling may contribute to dementia as well — highlighting the microbiome-brain axis as a promising target for preventing or attenuating neurodegenerative disease progression. In several ongoing projects, we focus on the role of the apolipoprotein E e4 allele, which is the strongest known genetic risk factor for Alzheimer’s disease, and its impact on the gut microbiome and neurocognition (ERC Starting Grant “MemoryLane”, BBRF Young Investigator Grant).
Besides dementia risk, gut microbes may also mediate the (often) detrimental effects of stress on brain function. In a recent paper, we demonstrated that the rise of stress hormones after acute stress (induced with a standardised laboratory measure) depends on one’s gut microbial diversity and inferred capacity to produce short-chain fatty acids (Karner et al., 2025) – microbially-synthesised metabolites that can cross the blood-brain barrier and impact hippocampus-dependent cognition.
Finally, we are interested in the early stages of life. In a currently ongoing project, we are investigating the effects of early gut microbiome-immune perturbation due to extremely premature birth on the development of brain networks and neurocognition in children (FWF Research Group “NeoGIBA”).
Cognitive neuroscience of
memory and spatial navigation
Microbiome-brain interactions lie at the heart of our research endeavours, but we have been devoting much time and effort to understanding the basic principles of neurocognition, particularly hippocampus-dependent memory and spatial navigation.
Prior work investigated the neural correlates of episodic memory formation and retrieval (Wagner et al., 2015, 2016, 2017, 2019), the beneficial effect of memory training (Ren et al., 2025; Wagner et al., 2021; Dresler et al., 2017) and exercise (van Dongen et al., 2016) on neurocognition, and the involvement of spatially-tuned cells in the entorhinal cortex that may contribute to our “internal compass”, allowing for successful orientation and navigation through space (Graichen et al., 2025; Wagner et al., 2023 — funded by an FWF Principal Investigator Project).
Check here for a full list of publications.
