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Biology subjects

Lai, O.

Publications and source records attributed to Lai, O..

2 recordsLinked to original sources

Contrastive learning for cell division detection and tracking in live cell imaging data

Fluorescent live-cell microscopy is essential for understanding cellular dynamics by imaging specific molecules, their interactions, and biochemical states in live samples. It is crucial for biological research and drug screening. However, live-cell imaging often requires balancing temporal resolution with cell viability (i.e. conditions enabling cells to thrive) because of photo-toxicity. Consequently, there is increasing interest in lowering temporal resolution to allow for extended observation periods and to study event sequences that uncover causal relationships and mechanistic insights. Tracking cells in video microscopy with low temporal resolution remains a challenge. We introduce a new integrated methodology that uses contrastive learning and graph-based approaches to improve cell division detection and tracking. Our approach employs contrastive learning models to create cell representations that facilitate the detection of cell divisions and enhance cell tracking. Of note, we propose a weakly-supervised constrastive learning approach to build robust temporal cell representations through time-based augmentations. Additionally, we introduce an innovative graph optimization technique to identify cell tracks based on these representations and observed division events. We evaluate our methods on an in-house dataset and public datasets from the Cell Tracking Challenge, achieving substantial performance improvements in both native and reduced temporal resolutions. Our methodology thus enhances adaptability to various temporal resolutions, improving precision and efficiency in live-cell microscopy analysis. This advancement is particularly beneficial for extended drug screening studies, ensuring cell viability and maintaining normal cell homeostasis, which is vital for therapeutic research.

bioinformatics↗

Discriminative and affective touch converge: Somatosensory cortex represents A-beta input in a CT-like manner

Current theory divides the human mechanical sense into discriminative and affective systems. A discriminative system supports tactile exploration and manipulation via fast A{beta} signaling, whereas an affective system supports the pleasure of friendly interpersonal touch via slow CT signaling. To probe this system segregation, we recorded the electroencephalogram from participants being stroked and reporting stroke pleasantness. We observed a somatosensory negativity that was maximal for CT optimal as compared with sub-optimal velocities, that predicted subjective pleasantness, and showed only for stroking of hairy skin known to be CT innervated. Importantly, the latency of this negativity preceded C fiber input to the brain by several hundred milliseconds and is best explained by interactions between CT and A{beta} processes in the spinal cord. Our data challenge the divide between discriminative and affective touch implying instead that both fast A{beta} and slow CT signaling play an important role in tactile pleasure.

neuroscience↗