Biology subjects

Thompson, A. C.

Publications and source records attributed to Thompson, A. C..

5 recordsLinked to original sources

bioRxiv2026

Developmental Chlorpyrifos Exposure Disrupts Tectal Circuit Formation and Behavior in Xenopus laevis

Developmental exposure to organophosphate pesticides has been associated with adverse neurodevelopmental outcomes, but the circuit-level mechanisms underlying these effects remain poorly understood. Here, we examined how low-level chlorpyrifos (CPF) exposure affects neural circuit maturation and behavior in Xenopus laevis tadpoles. Tadpoles were exposed to 1 {micro}M CPF from developmental stage 42 to stage 49, spanning a critical period of synaptogenesis and circuit refinement. CPF-exposed tadpoles displayed abnormal schooling behavior, characterized primarily by impaired body-axis alignment despite preserved group aggregation, as well as altered spontaneous swimming marked by reduced looping and increased seizure-like activity. Whole-cell recordings from tectal neurons revealed persistent reductions in inhibitory synaptic drive, consistent with altered excitation-inhibition balance. Although acute CPF exposure transiently increased intrinsic excitability of tectal neurons as well as baseline swimming activity, this effect was not maintained after chronic exposure. Morphological analysis of GFP-labeled tectal neurons revealed altered dendritic branching distribution despite no change in total dendritic length or branch number. Together, these findings suggest that developmental CPF exposure disrupts tectal circuit maturation, leading to abnormal neural connectivity and maladaptive behavioral outcomes relevant to neurodevelopmental dysfunction.

neuroscience↗

bioRxiv2025

Compact Vision--Language Models Enable Efficient and Interpretable Automated OCT Analysis Through Layer Specific Multimodal Learning

Translating the intricate anatomical signatures of retinal disease from OCT B-scans into clear, accurate clinical narratives demands AI models that seamlessly fuse visual features with domain expertise. We curated a multimodal dataset of 40,000 OCT B-scans from public repositories and private clinical cohorts, each paired with expert validated summaries spanning six conditions: diabetic macular edema, diabetic retinopathy, geographic atrophy, drusen, choroidal neovascularization, and healthy retina. We introduce LO-VLM, a compact (247M parameter) vision-language model (VLM) that infuses anatomical guidance into both encoder and decoder for free form summary generation and multiclass disease classification. Benchmarking against state-of-the-art RetinaVLM, LLaVA-Med, and a ViT vision only model demonstrates superior performance. In a blinded evaluation by three board certified retina specialists scored the generated summaries, LO-VLM narratives achieved mean = 8.5 (standard deviation = 1.15) out of 10, compared to mean = 5.5 (standard deviation = 1.13) for RetinaVLM (p < 0.0001). In quantitative evaluations, LO-VLM achieved an SBERT similarity of 0.803 and a BERTScore F1 of 0.715, representing improvements of 8.2% and 28.8% over specialized VLM baselines. For disease classification, LO-VLM reached 96% accuracy (F1 = 96%), outperforming ViT by 13% and exceeding medical VLM benchmarks by over 62%. By reconciling interpretability with computational efficiency, LO-VLM establishes a new paradigm for efficient AI models in OCT interpretation.

bioengineering↗

bioRxiv2024

Emergence and interstate spread of highly pathogenic avian influenza A(H5N1) in dairy cattle

Highly pathogenic avian influenza (HPAI) viruses cross species barriers and have the potential to cause pandemics. In North America, HPAI A(H5N1) viruses related to the goose/Guangdong 2.3.4.4b hemagglutinin phylogenetic clade have infected wild birds, poultry, and mammals. Our genomic analysis and epidemiological investigation showed that a reassortment event in wild bird populations preceded a single wild bird-to-cattle transmission episode. The movement of asymptomatic cattle has likely played a role in the spread of HPAI within the United States dairy herd. Some molecular markers in virus populations were detected at low frequency that may lead to changes in transmission efficiency and phenotype after evolution in dairy cattle. Continued transmission of H5N1 HPAI within dairy cattle increases the risk for infection and subsequent spread of the virus to human populations.

microbiology↗

bioRxiv2021

Regulation of Nav1.6-mediated sodium currents underlie the homeostatic control of neuronal intrinsic excitability in the optic tectum of the developing Xenopus laevis tadpole

For individual neurons to function appropriately within a network that is undergoing synaptic reorganization and refinement due to developmental or experience-dependent changes in circuit activity, they must homeostatically adapt their intrinsic excitability to maintain a consistent output despite the changing levels of synaptic input. This homeostatic plasticity of excitability is particularly important for the development of sensory circuits, where subtle deficits in neuronal and circuit function cause developmental disorders including autism spectrum disorder and epilepsy. Despite the critical importance of this process for normal circuit development, the molecular mechanism by which this homeostatic control of intrinsic excitability is regulated is not fully understood. Here, we demonstrate that Xenopus optic tectal neurons express distinct fast, persistent and resurgent Na+ currents. Here, we demonstrate that Xenopus optic tectal neurons express distinct fast, persistent and resurgent Na+ currents. These are regulated with developmental changes in synaptic input, and homeostatically in response to changes in visual input. We show that expression of the voltage-gated Na+ channel subtype Nav1.6 is regulated with changes in intrinsic excitability, that blocking Nav1.6 channels is sufficient to decrease intrinsic excitability. Furthermore, that upregulation of Nav1.6 expression is necessary for experience-dependent increases in Na+ currents and intrinsic excitability. Finally, by examining behaviors that rely on visual and multisensory integration, we extend these findings to show that tight regulation of Na+ channel gene expression during a critical period of tectal circuit development is required for the normal functional development of the tectal circuitry.

neuroscience↗

bioRxiv2020

Hybrid optogenetic and electrical stimulation for greater spatial resolution and temporal fidelity of cochlear activation

Compared to electrical stimulation, optogenetic stimulation has the potential to improve the spatial precision of neural activation in neuroprostheses, but it requires intense light and has relatively poor temporal kinetics. We tested the effect of hybrid stimulation, which is the combination of subthreshold optical and electrical stimuli, on spectral and temporal fidelity in the cochlea by recording multiunit activity in the inferior colliculus of channelrhodopsin (H134R variant) transgenic mice. Pulsed light or biphasic electrical pulses were delivered to cochlear spiral ganglion neurons of acutely deafened mice, either as individual stimuli or as hybrid stimuli for which the timing of the electrical pulse had a varied delay relative to the start of the optical pulse. Facilitation occurred when subthreshold electrical stimuli were applied at the end of, or up to 3.75 ms after subthreshold optical pulses. The spread of activation resulting from hybrid stimulation was significantly narrower than electrical-only and optical-only stimulation (p<0.01), measured at equivalent suprathreshold levels of loudness that are relevant to cochlear implant users. Furthermore, temporal fidelity, measured as maximum following rates to 300 ms pulse trains bursts up to 240 Hz, was 2.4-fold greater than optical-only stimulation (p<0.05). By significantly improving spectral resolution of electrical- and optical-only stimulation and the temporal fidelity of optical-only stimulation, hybrid stimulation has the potential to increase the number of perceptually independent stimulating channels in a cochlear implant.

neuroscience↗