Biology subjects

Tung, R.

Publications and source records attributed to Tung, R..

4 recordsLinked to original sources

bioRxiv2025

Interruption of rat absence seizures by auditory stimulation

Absence seizures are episodes of impaired consciousness and responsiveness that impact an individuals ability to interact with the world around them. Childhood absence epilepsy, a condition defined by these seizures, can have profound effects on childrens social, educational, and psychological development. Absence seizures are accompanied by a distinctive electrographic signature called a spike-wave discharge. The impairment of consciousness associated with a spike-wave discharge can be variable: some people maintain responsiveness during some absence seizures, and some rodent oscillations resembling spike-wave discharges may not have any behavioral impact. We previously observed that spike-wave discharges in the Genetic Absence Epilepsy Rat from Strasbourg model sometimes terminated shortly after presentation of a conditioned auditory stimulus. In this study we found that these terminations were caused by the stimuli and that they occurred after approximately 50% of stimuli. We also found that the probability of a spike-wave discharge being interrupted depended on stimulus timing, degree of conditioning, and electrographic signal power. These data provide insight into the factors that determine the mechanisms of absence seizure termination, with possible implications for therapy.

neuroscience↗

bioRxiv2023

Gut microbiota and faecal cytokine profiles of rural Cambodian infants and links to early life nutrition and diarrhoeal episodes.

The gut microbiota of infants in low-middle income countries like Cambodia remain underrepresented in microbiome research. This study aimed to explore the faecal gut microbiota composition and faecal cytokine profiles in a cohort of infants living in a rural province of Cambodia and explore the impact of sample storage conditions and infant environment on microbiota composition. Faecal samples collected at three time points from 32 infants (96 samples in total) after 7 months of age were analysed using 16S rRNA amplicon sequencing to determine the composition of the microbiota. Bacterial strains were isolated and subjected to whole genome sequencing and genomic analysis and concentrations of faecal cytokines were also measured. Initially, we compared the effects of two sample collection methods due to the challenges of faecal sample collection and storage in a rural location. Storage of faecal samples in a DNA preservation solution retained a greater abundance of Bacteroides. Analyses of microbiota composition of samples stored in DNA preservation solution indicated that Bifidobacterium was the most abundant genus with Bifidobacterium longum the most abundant species, particularly in breastfed infants. Most infants had detectable pathogenic taxa indicating frequent pathogen exposure, with Shigella and Klebsiella more abundant in infants with recent diarrheal illness. We did not detect antibiotic-associated perturbations in the gut microbiota, and no associations were found between the gut microbiota and infant growth. Genomic analysis of isolated strains indicated the presence of gene clusters encoding the ability to digest human milk oligosaccharides in B. longum and Bifidobacterium breve isolates. The presence of antibiotic-resistant genes was also identified in potentially pathogenic species, as well as in beneficial genera including Bifidobacterium. Faecal cytokine analysis showed higher concentrations of Interlukin-1alpha and vascular endothelial growth factor in breastfed infants, which may influence the infant gut mucosal immune system. This study provides insights into an underrepresented population of rural Cambodian infants, emphasising the impact of pathogen exposure and breastfeeding on gut microbiota composition and faecal immune profiles.

microbiology↗

bioRxiv2022

Facemap: a framework for modeling neural activity based on orofacial tracking

Recent studies in mice have shown that orofacial behaviors drive a large fraction of neural activity across the brain. To understand the nature and function of these signals, we need better computational models to characterize the behaviors and relate them to neural activity. Here we developed Facemap, a framework consisting of a keypoint tracking algorithm and a deep neural network encoder for predicting neural activity. We used the Facemap keypoints as input for the deep neural network to predict the activity of [~]50,000 simultaneously-recorded neurons and in visual cortex we doubled the amount of explained variance compared to previous methods. Our keypoint tracking algorithm was more accurate than existing pose estimation tools, while the inference speed was several times faster, making it a powerful tool for closed-loop behavioral experiments. The Facemap tracker was easy to adapt to data from new labs, requiring as few as 10 annotated frames for near-optimal performance. We used Facemap to find that the neuronal activity clusters which were highly driven by behaviors were more spatially spread-out across cortex. We also found that the deep keypoint features inferred by the model had time-asymmetrical state dynamics that were not apparent in the raw keypoint data. In summary, Facemap provides a stepping stone towards understanding the function of the brainwide neural signals and their relation to behavior.

neuroscience↗

bioRxiv2021

Decreased overall neuronal activity in a rodent model of impaired consciousness during absence seizures

Absence seizures are characterized by a brief behavioural impairment including apparent loss of consciousness. Neuronal mechanisms determining the behavioural impairment of absence seizures remain unknown, and their elucidation might highlight therapeutic options for reducing seizure severity. However, recent studies have questioned the similarity of animal spike-wave-discharges (SWD) to human absence seizures both behaviourally and neuronally. Here, we report that Genetic Absence Epilepsy Rats from Strasbourg recapitulate the decreased neuroimaging signals and loss of consciousness characteristic of human absence seizures. Overall neuronal firing is decreased but rhythmic in the somatosensory cortex and thalamus during these seizures. Interestingly, individual neurons in both regions tend to consistently express one of four distinct patterns of seizure-associated activity. These patterns differ in firing rate dynamics and in rhythmicity during seizure. One group of neurons showed a transient initial peak in firing at SWD onset, accounting for the brief initial increase in overall neuronal firing seen in cortex and thalamus. The largest group of neurons in both cortex and thalamus showed sustained decreases in firing during SWD. Other neurons showed either sustained increases or no change in firing. These findings suggest that certain classes of cortical and thalamic neurons may be particularly responsible for the paroxysmal oscillations and consequent loss of consciousness in absence epilepsy.

neuroscience↗