Biology subjects

Galvis, D.

Publications and source records attributed to Galvis, D..

4 recordsLinked to original sources

bioRxiv2025

Plasmonic imaging of living pancreatic beta-cell networks

We present a novel plasmonic imaging technique for real-time, label-free tracking of bioelectrical interactions in live pancreatic beta-cell networks. Surface plasmon resonance microscopy (SPRM) is utilized to reveal synchronized glucose-induced intensity oscillations that are suppressed by calcium channel blockers. These oscillations are observed at the subcellular scale with a resolution of 1 m. The technique can also uncover the extracellular spread of these oscillations beyond the cells. We further combine SPRM with network analysis to quantify coordinated electrical activity within the living cell network using both amplitude and phase-based metrics. Our results demonstrate a new method for studying electrical communication in pancreatic beta-cells, which could be crucial for understanding dysregulation in diabetes and advancing treatment development. This technique holds promise for investigating electrical connectivity in biological cell networks with applications in neuroscience, cardiac science, and bioelectricity in cancer, microbiology, development and regeneration. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/649945v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1dc0ce1org.highwire.dtl.DTLVardef@1d1c333org.highwire.dtl.DTLVardef@6684acorg.highwire.dtl.DTLVardef@906170_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2023

Using compartmental models to understand excitation-inhibition imbalance in epilepsy

Epileptic seizures are characterized by abnormal synchronous bursting of neurons. This is commonly attributed to an imbalance between excitatory and inhibitory neurotransmission. We introduce compartmental models from epidemiology to study this interaction between excitatory and inhibitory populations of neurons in the context of epilepsy. Neurons could either be bursting or susceptible, and the propagation of action potentials within the brain through the bursting of neurons is considered as an infection spreading through a population. We model the recruitment of neurons into bursting and their subsequent decay to susceptibility to be influenced by the proportion of excitatory and inhibitory neurons bursting, resulting in a two population Susceptible - Infected - Susceptible (SIS) model. This approach provides a tractable framework to inspect the mechanisms behind seizure generation and termination. Considering the excitatory neurotransmission as an epidemic spreading through the neuronal population and the inhibitory neurotransmission as a competing epidemic that stops the spread of excitation, we establish the conditions for a seizure-like state to be stable. Subsequently, we show how an activity-dependent dysfunction of inhibitory mechanisms such as impaired GABAergic inhibition or inhibitory-inhibitory interactions could result in a seizure even when the above conditions are not satisfied.

neuroscience↗

bioRxiv2023

The impact of paediatric epilepsy and co-occurring neurodevelopmental disorders on functional brain networks in wake and sleep

Epilepsy is one of the most common neurological disorders in children. Diagnosing epilepsy in children can be very challenging, especially as it often coexists with neurodevelopmental conditions like autism and ADHD. Functional brain networks obtained from neuroimaging and electrophysiological data in wakefulness and sleep have been shown to contain signatures of neurological disorders, and can potentially support the diagnosis and management of co-occurring neurodevelopmental conditions. In this work, we use electroencephalography (EEG) recordings from children, in restful wakefulness and sleep, to extract functional connectivity networks in different frequency bands. We explore the relationship of these networks with epilepsy diagnosis and with measures of neurodevelopmental traits, obtained from questionnaires used as screening tools for autism and ADHD. We explore differences in network markers between children with and without epilepsy in wake and sleep, and quantify the correlation between such markers and measures of neurodevelopmental traits. Our findings highlight the importance of considering the interplay between epilepsy and neurodevelopmental traits when exploring network markers of epilepsy.

neuroscience↗

bioRxiv2021

The dynamic interaction of systemic inflammation and the hypothalamic-pituitary-adrenal (HPA) axis during and after major surgery

Major surgery and critical illness produce a potentially life threatening systemic inflammatory response. The hypothalamic-pituitary-adrenal (HPA) axis is one of the key physiological systems that counterbalances this systemic inflammation through changes in adrenocorticotrophic hormone (ACTH) and cortisol. These hormones normally exhibit highly correlated ultradian pulsatility with an amplitude modulated by circadian processes. However, these dynamics are disrupted by major surgery and critical illness. In this work, we characterise the inflammatory, ACTH and cortisol responses of patients undergoing cardiac surgery and show that the HPA axis response can be classified into one of three phenotypes: single-pulse, two-pulses and multiple-pulses dynamics. We develop a mathematical model of cortisol secretion and metabolism that predicts the physiological mechanisms responsible for these different phenotypes. We show that the effects of inflammatory mediators are important only in the single-pulse pattern in which normal pulsatility is lost - suggesting that this phenotype could be indicative of the greatest inflammatory response. Investigating whether and how these phenotypes are correlated with clinical outcomes will be critical to patient prognosis and designing interventions to improve recovery.

physiology↗