Biology subjects

Fieseler, C.

Publications and source records attributed to Fieseler, C..

5 recordsLinked to original sources

bioRxiv2026

Flexible modulation of neuronal population dynamics drives variable decision-making in C. elegans

Behavior arises from the interplay between spontaneous brain dynamics and sensory-driven responses, yet how spontaneous neural activity shapes variability in decision-making remains unclear. We leverage the tractable C. elegans nervous system to address this question. During oxygen avoidance, we observe binary trial-to-trial variability in behavioral responses. Whole-brain calcium imaging reveals a brain-wide sensory-to-motor transformation in which sensory neurons faithfully encode the stimulus but do not predict choice. Instead, decision-related information is distributed across interneurons and motor neurons, encoded through a neuronal subspace. This decision-biasing state evolves slowly during the pre-stimulus period, resembling preparatory dynamics for spontaneous behavioral transitions but receives neuromodulatory contributions. Optogenetic manipulations reveal that only a subset of neurons within this distributed representation are causally connected to choice. This reveals a dissociation between broad information sharing and control via dedicated localized nodes. Thus, response variability arises from slowly evolving modulation of brain states rather than stochastic circuit noise.

neuroscience↗

bioRxiv2025

BarlowTrack: A Self-Supervised Framework for Zero-Shot Multi-Object Cell Tracking

Recent advances in neuroscience have made it possible to image large brain regions at single-cell resolution. However, classic methods for processing these videos into neuronal time series fail in the presence of large and nonrigid deformations, in particular for freely moving animals. Several successful algorithms have been proposed to solve this problem in moving C. elegans, but they are highly specific to the conditions of a single research setting. We propose a tracking pipeline based on self-supervised learning that achieves a high level of zero-shot accuracy across conditions, and, for the first time, independent laboratories. We contribute a novel term in the Barlow Twins loss function to encourage decorrelation of features across detected instances at the same time point. To encourage broad adoption, we use the standardized Neurodata Without Borders (NWB) format and we provide a GUI for visualization of the final results and neuronal time series. Finally, we provide a benchmark of datasets with ground truth annotations in the NWB format for further algorithmic development.

bioinformatics↗

bioRxiv2025

Cerebral Organoids Uncover Mechanisms of Neural Activity Changes in Epileptogenesis

Neurological disorders often originate from progressive brain network dysfunctions that start years before symptoms appear. How these changes emerge in the developing human brain remains elusive due to a lack of tractable model systems. Here, we show a cerebral organoid model of Tuberous Sclerosis Complex (TSC) that recapitulates hallmarks of epileptogenesis in vitro. We compare extracellular recordings of TSC organoids with intraoperative electrocorticography from TSC patients to reveal striking functional similarities, including high-frequency oscillations - an electrical biomarker for epileptogenic tissue. In TSC, a human-specific interneuron sub-type derived from the caudal ganglionic eminence drives network hyper-synchronization through increased spontaneous firing and altered excitability. Inhibiting overproliferation of its progenitors via long-term epidermal growth factor receptor inhibition prevented the onset of this pathological phenotype at functional and morphological levels. Our work shows that organoids allow mechanistic analysis of emerging neural network phenotypes, enabling anti-epileptogenic drug testing in a human brain development model.

neuroscience↗

bioRxiv2025

An intrinsic neuronal manifold underlies brain-wide hierarchical organization of behavior in C. elegans

Large-scale neuronal recordings in various species have revealed behavior-related activity patterns. Surprisingly, these activities are distributed across brain regions, including sensory areas. However, their origins and functions are incompletely understood. Using whole-brain imaging in freely behaving C. elegans, we discover that such distributed brain activity is dominated by a low dimensional manifold, corresponding to the major action sequence of C. elegans. The manifold originates largely from intrinsic dynamics, with minor contributions from movement-induced sensations. We discover a new function of the manifold: to gate the activity of a large number of neuron classes. This gating constrains them to selectively encode faster time-scale motor patterns during specific brain states. We therefore propose that one principle function of brain-wide dynamics is to enable hierarchical organization of behavior: information about major actions is broadcast via a distributed manifold, to enable nesting of granular motor patterns within those major actions.

neuroscience↗

bioRxiv2021

Twenty years of change in benthic communities across the Belizean Barrier Reef

Disease, ocean warming, and pollution have caused catastrophic declines in the cover of living coral on reefs across the Caribbean. Subsequently, reef-building corals have been replaced by invertebrates and macroalgae, leading to changes in ecological functioning. We describe changes in benthic community composition and cover at 15 sites across the Belizean Barrier Reef (BBR) following numerous major disturbances--bleaching, storms, and disease outbreaks--over the 20-year period 1997-2016. We tested the role of potential drivers of change on coral reefs, including local human impacts and ocean temperature. From 1997 to 2016, mean coral cover significantly declined from 26.3% to 10.7%, while macroalgal cover significantly increased from 12.9% to 39.7%. We documented a significant decline over time of the reef-building corals Orbicella spp. and described a major shift in benthic composition between early sampling years (1997-2005) and later years (2009-2016). The covers of hard-coral taxa, including Acropora spp., M. cavernosa, Orbicella spp., and Porites spp., were negatively related to marine heatwave frequency. Only gorgonian cover was related, negatively, to our metric of the magnitude of local impacts (the Human Influence Index). Changes in benthic composition and cover were not associated with local protection or fishing. This result is concordant with studies throughout the Caribbean that have documented living coral decline and shifts in reef-community composition following disturbances, regardless of local fisheries restrictions. Our results suggest that benthic communities along the BBR have experienced disturbances that are beyond the capacity of the current management structure to mitigate. We recommend that managers devote greater resources and capacity to enforce and expand existing marine protected areas and that government, industry, and the public act to reduce global carbon emissions.

ecology↗