Biology subjects

Solca, M.

Publications and source records attributed to Solca, M..

3 recordsLinked to original sources

bioRxiv2025

Tracking the Spread of a Naturally Occurring Leishmania infantumMutant: A qPCR-Based Investigation in Strains and Clinical Samples

The circulation of Leishmania infantum strains carrying a 12 Kb genomic deletion (DEL) alongside wild-type (NonDEL) parasites in the Americas raises critical epidemiological questions. To support molecular surveillance efforts, we developed and validated a qPCR-based genotyping tool capable of detecting and quantifying DEL, NonDEL, and coinfection (MIX) profiles. The strategy targets a constitutive region present in all strains and a specific region exclusive to NonDEL parasites. It was validated using DNA from cultured parasites and applied to a panel of diverse clinical samples from dogs, humans, and other hosts across South and Central America. DEL genotypes were found to be more frequent and widespread, both in clinical samples and cultured parasites, suggesting their significant role in the transmission cycle. The tools application revealed coinfections in paired samples and enabled relative quantification of genotypes. It also showed good correlation with parasite load estimations and high discriminatory power when integrated with the Genotype function of real-time PCR software. This protocol provides a robust, scalable approach for monitoring L. infantum genotypes, with direct implications for understanding infection dynamics, treatment outcomes and public health surveillance. Author SummaryLeishmania infantum is the parasite responsible for visceral leishmaniasis in the Americas. Recent studies have shown that two distinct genotypes--those carrying a specific gene deletion (DEL) and those without it (NonDEL)--coexist and circulate in the region. Understanding how these genotypes are distributed and whether they affect disease transmission or treatment is critical, especially because Miltefosine, a drug used to treat dogs, may not work equally well against both genotypes. In this study, we developed a simple and accurate molecular test to detect and quantify these genotypes in both cultured parasites and clinical samples from different animal hosts, including humans. We found that DEL genotypes are common and widely distributed, and that some animals carry both types of parasites simultaneously. Our method also distinguishes L. infantum from other related species, making it useful for diagnosis and surveillance. This tool can help researchers and health authorities monitor parasite populations more effectively and better understand how different genotypes might impact disease outcomes and control strategies.

microbiology↗

bioRxiv2023

Human primary motor cortex indexes the onset of subjective intention in brain-machine-interface mediated actions

Self-initiated behavior is accompanied by the experience of willing our actions. Here, we leverage the unique opportunity to examine the full intentional chain - from will (W) to action (A) to environmental effects (E) - in a tetraplegic person fitted with a primary motor cortex (M1) brain machine interface (BMI) generating hand movements via neuromuscular electrical stimulation (NMES). This combined BMI-NMES approach allowed us to selectively manipulate each element of the intentional chain (W, A, and E) while performing extra-cellular recordings and probing subjective experience. Our results reveal single-cell, multi-unit, and population-level dynamics in human M1 that encode W and may predict its subjective onset. Further, we show that the proficiency of a neural decoder in M1 reflects the degree of W-A binding, tracking the participants subjective experience of intention in (near) real time. These results point to M1 as a critical node in forming the subjective experience of intention and demonstrate the relevance of intention-related signals for translational neuroprosthetics.

neuroscience↗

bioRxiv2022

Single neurons in thalamus and subthalamic nucleus process cardiac and respiratory signals in humans

Visceral signals are constantly processed by our central nervous system, enable homeostatic regulation, and influence perception, emotion, and cognition. While visceral processes at cortical level have been extensively studied using non-invasive imaging techniques, very few studies have investigated how this information is processed at the single neuron level, both in humans and animals. Subcortical regions, relaying signals from peripheral interoceptors to cortical structures, are particularly understudied and how visceral information is processed in thalamic and subthalamic structures remains largely unknown. Here, we took advantage of intraoperative microelectrode recordings in patients undergoing surgery for deep brain stimulation (DBS) to investigate the activity of single neurons related to cardiac and respiratory functions in three subcortical regions: Ventral Intermedius nucleus (Vim) and Ventral caudalis nucleus (Vc) of the thalamus, and subthalamic nucleus (STN). We report that the activity of a large portion of the recorded neurons (about 70%) was modulated by either the heartbeat, the cardiac inter-beat interval, or the respiration. These cardiac and respiratory response patterns varied largely across neurons both in terms of timing and their kind of modulation. We observed neurons with increases or decreases in firing rate in response to either the heartbeat or the inter-beat interval. Peaks of neural activity were found at different phases of the cardiac and respiratory cycles. Whereas most neurons only responded to one of the tested signals, a substantial proportion of these visceral neurons (30%) was responsive to more than one of the tested signals, underlining specialization and integration of cardiac and respiratory signals in STN and thalamic neurons. By extensively describing for the first time single unit activity related to cardiorespiratory function in thalamic and subthalamic neurons, our results highlight the major role of these subcortical regions in the processing of visceral signals.

neuroscience↗