Biology subjects

Scholz, L. A.

Publications and source records attributed to Scholz, L. A..

6 recordsLinked to original sources

bioRxiv2025

Plug-and-Play automated behavioral tracking of zebrafish larvae with DeepLabCut and SLEAP: pre-trained networks and datasets of annotated poses

Zebrafish are an important model system in behavioral neuroscience due to their rapid development and suite of distinct, innate behaviors. Quantifying many of these larval behaviors requires detailed tracking of eye and tail kinematics, which in turn demands imaging at high spatial and temporal resolution, ideally using semi or fully automated tracking methods for throughput efficiency. However, creating and validating accurate tracking models is time-consuming and labor intensive, with many research groups duplicating efforts on similar images. With the goal of developing a useful community resource, we trained pose estimation models using a diverse array of video parameters and a 15-keypoint pose model. We deliver an annotated dataset of free-swimming and head-embedded behavioral videos of larval zebrafish, along with four pose estimation networks from DeepLabCut and SLEAP (two variants of each). We also evaluated model performance across varying imaging conditions to guide users in optimizing their imaging setups. This resource will allow other researchers to skip the tedious and laborious training steps for setting up behavioral analyses, guide model selection for specific research needs, and provide ground truth data for benchmarking new tracking methods. SIGNIFICANCE STATEMENTLarval zebrafish are an emerging model in systems neuroscience, offering unique advantages for linking brain activity to behavior. However, detailed behavioral tracking, essential for such studies, requires time- and labor-intensive annotation and model training. To eliminate this bottleneck, here we provide a high-quality, annotated dataset of zebrafish behaviors for both free-swimming and head-embedded preparations alongside four pre-trained pose estimation models using DeepLabCut and SLEAP. We benchmark models performance across diverse imaging conditions to guide optimal setup choices. This community resource will allow researchers to bypass the most time-consuming stages of data annotation and training, enabling immediate behavioral analysis. By removing this key hurdle, this work will accelerate project initiation, support reproducibility, and provide a foundation for future tracking method development.

animal behavior and cognition↗

bioRxiv2024

Brain-wide circuitry underlying altered auditory habituation in zebrafish models of autism.

Auditory processing is widely understood to occur differently in autism, though the patterns of brain activity underlying these differences are not well understood. The diversity of autism also means brain-wide networks may change in various ways to produce similar behavioral outputs. We used larval zebrafish to investigate auditory habituation in four genetic lines relevant to autism: fmr1, mecp2, scn1lab and cntnap2. In free-swimming behavioral tests, we found each line had a unique profile of auditory hypersensitivity and/or delayed habituation. Combining the optical transparency of larval zebrafish with genetically encoded calcium indicators and light-sheet microscopy, we then observed brain-wide activity at cellular resolution during auditory habituation. As with behavior, each line showed unique alterations in brain-wide spontaneous activity, auditory processing, and adaptation in response to repetitive acoustic stimuli. We also observed commonalities in activity across our genetic lines that indicate shared circuit changes underlying certain aspects of their behavioral phenotypes. These were predominantly in regions involved in sensory integration and sensorimotor gating rather than primary auditory areas. Overlapping phenotypes include differences in the activity and functional connectivity of the telencephalon, thalamus, dopaminergic regions, and the locus coeruleus, and excitatory/inhibitory imbalance in the cerebellum. Unique phenotypes include loss of activity in the habenula in scn1lab, increased activity in auditory regions in fmr1, and differences in network activity over time in mecp2 and cntnap2. Comparing these distinct but overlapping brain-wide auditory networks furthers our understanding of how diverse genetic factors can produce similar behavioral effects through a range of circuit- and network-scale mechanisms.

neuroscience↗

bioRxiv2024

Brain-wide impacts of sedation on spontaneous activity and auditory processing in larval zebrafish

Despite their widespread use, we have limited knowledge of the mechanisms by which sedatives mediate their effects on brain-wide networks. This is, in part, due to the technical challenge of observing activity across large populations of neurons in normal and sedated brains. In this study, we examined the effects of the sedative dexmedetomidine, and its antagonist atipamezole, on spontaneous brain dynamics and auditory processing in zebrafish larvae. Our brain-wide, cellular-resolution calcium imaging reveals, for the first time, the brain regions involved in these network-scale dynamics and the individual neurons that are affected within those regions. Further analysis reveals a variety of dynamic changes in the brain at baseline, including marked reductions in spontaneous activity, correlation, and variance. The reductions in activity and variance represent a "quieter" brain state during sedation, an effect that causes highly correlated evoked activity in the auditory system to stand out more than it does in un-sedated brains. We also observe a reduction in auditory response latencies across the brain during sedation, suggesting that the removal of spontaneous activity leaves the core auditory pathway free of impingement from other non-auditory information. Finally, we describe a less dynamic brain-wide network during sedation, with a higher energy barrier and a lower probability of brain state transitions during sedation. In total, our brain-wide, cellular-resolution analysis shows that sedation leads to quieter, more stable, and less dynamic brain, and that against this background, responses across the auditory processing pathway become sharper and more prominent. Significance StatementAnimals brain states constantly fluctuate in response to their environment and context, leading to changes in perception and behavioral choices. Alterations in perception, sensorimotor gating, and behavioral selection are hallmarks of numerous neuropsychiatric disorders, but the circuit- and network-level underpinnings of these alterations are poorly understood. Pharmacological sedation alters perception and responsiveness and provides a controlled and repeatable manipulation for studying brain states and their underlying circuitry. Here, we show that sedation of larval zebrafish with dexmedetomidine reduces brain-wide spontaneous activity and locomotion but leaves portions of brain-wide auditory processing and behavior intact. We describe and computationally model changes at the levels of individual neurons, local circuits, and brain-wide networks that lead to altered brain states and sensory processing during sedation.

neuroscience↗

bioRxiv2020

Broad frequency sensitivity and complex neural coding in the larval zebrafish auditory system

Most animals have complex auditory systems that identify salient features of the acoustic landscape to direct appropriate responses. In fish, these features include the volume, frequency, complexity, and temporal structure of auditory stimuli transmitted through water. Larval fish have simple brains compared to adults, but swim freely and depend on sophisticated sensory processing for survival. Zebrafish larvae, an important model for studying brain-wide neural networks, have thus far been found to possess a rudimentary auditory system, sensitive to a narrow range of frequencies and without evident sensitivity to auditory features that are salient and ethologically important to adult fish. Here, we have combined a novel method for delivering water-borne sounds, a diverse assembly of acoustic stimuli, and whole-brain calcium imaging to describe the responses of individual auditory neurons across the brains of zebrafish larvae. Our results reveal responses to frequencies ranging from 100Hz to 4kHz, with evidence of frequency discrimination from 100Hz to 2.5kHz. Frequency-selective neurons are located in numerous regions of the brain, and neurons responsive to the same frequency are spatially grouped in some regions. Using functional clustering, we identified categories of neurons that are selective for pure tones of a single frequency, white noise, the sharp onset of auditory stimuli, and stimuli involving a gradual crescendo. These results suggest a more nuanced auditory system than has previously been described in larval fish and provide insights into how a young animals auditory system can both function acutely and serve as the scaffold of a more complex adult system.

neuroscience↗

bioRxiv2019

Factorial design as a tool to evaluate image analysis workflows systematically: its application to the filament tracing problem

The effect of image enhancement methods on the final result of image analysis workflows is often left out of discussions in scientific papers. In fact, before reaching a definitive enhancement workflow and its settings, there often is a great amount of pre-testing and parameter tweaking. In this work, we take the biofilament tracing problem and propose a systematic approach to testing and evaluating major image enhancement methods that are applied prior to execution of six filament tracing methods (APP, APP2, FarSIGHT Snake, NeuronStudio, Neutube and Rivulet2). We used a full factorial design of experiments to analyse five enhancement methods (deconvolution, background subtraction, pixel intensity normalization, Frangi vessel enhancement and smoothing) and the order in which they are applied, evaluating their effect on the signal-to-noise ratio, structural similarity index and geometric tracing scores of 3D images of a fungal mycelium and a synthetic neuronal tree. Our approach proved valuable as a tool to support the choice of enhancement and filament tracing workflow. For example, the use of deconvolution followed by median filtering gives the best geometric tracing scores if Neutube is used in the image of the fungal mycelium. Also, we show that FarSIGHT Snake and Neutube are the most robust filament tracing methods to changes in image quality. In addition, we reinforce the importance of extensive testing of new filament tracing methods against a broad range of image qualities and filament characteristics.

bioinformatics↗

bioRxiv2019

BIAFLOWS: A collaborative framework to benchmark bioimage analysis workflows

Automated image analysis has become key to extract quantitative information from scientific microscopy bioimages, but the methods involved are now often so refined that they can no longer be unambiguously described using written protocols. We introduce BIAFLOWS, a software tool with web services and a user interface specifically designed to document, interface, reproducibly deploy, and benchmark image analysis workflows. BIAFLOWS allows image analysis workflows to be compared fairly and shared in a reproducible manner, safeguarding research results and promoting the highest quality standards in bioimage analysis. A curated instance of BIAFLOWS is available online; it is currently populated with 34 workflows that can be triggered to process image datasets illustrating 15 common bioimage analysis problems organized in 9 major classes. As a complete case study, the open benchmarking of 7 nuclei segmentation workflows, including classical and deep learning techniques, was performed on this online instance. All the results presented can be reproduced online.

bioinformatics↗