Results for “Patch-Clamp Techniques”

PubMed2026

Biophysical mechanisms underlying the generation and maintenance of rule-learning engram.

Training rodents in a particularly difficult olfactory-discrimination task results with acquisition of high-skill to perform the task superbly, termed 'rule-learning'. We show that rule-learning occurs abruptly, in a "light-bulb moment". Using whole-cell patch-clamp recordings from the piriform cortex (PC) of Fos2A-iCreER/TRAP2 mice, we target activated-neurons, expressing immediate early genes (IEG). We notice, from the onset of training, IEG-positive neurons from trained animals display enhanced intrinsic excitability. Subsequently, synaptic excitation and inhibition are enhanced in these neurons, in a coordinated, cell-wide process. Additionally, in parallel, we detect the density of IEG-expressing neurons sharply declines. Double labeling with TRAP and c-Fos reveal that nearly two-thirds of the rule-memory cell ensemble neurons are activated from the beginning of training. Silencing TRAP-expressing neurons using inhibitory DREADD leads to a complete loss of rule memory. Hence, we propose that rule learning occurs at a discrete moment and is developed through a gradual process that stabilizes the memory of the rule.

Animals↗

PubMed2026

Automated patch clamp data improve variant classification and penetrance stratification for SCN5A-Brugada syndrome.

BACKGROUND AND AIMS: Brugada Syndrome (BrS) is an inherited arrhythmia disorder that causes an elevated risk of sudden cardiac death. Approximately 20% of patients with BrS have rare variants in SCN5A, which encodes the cardiac sodium channel NaV1.5. Genetic workup of BrS is often complicated by SCN5A variants of uncertain significance (VUS) and/or incomplete penetrance. This study deployed an SCN5A-BrS functional assay at cohort scale to facilitate the implementation of genetic and precision medicine. METHODS: All 252 missense and in-frame insertion/deletion SCN5A variants from a previously published large cohort of BrS cases (n = 3335 patients) were analysed using a calibrated high-throughput automated patch-clamp (APC) assay. Variant functional Z-scores were assigned evidence levels ranging from BS3_moderate (normal function) to PS3_strong (loss-of-function), as defined by American College of Medical Genetics and Genomics criteria. Functional evidence was combined with population frequency, hotspot, case counts, protein-length changes, and in silico predictions. Odds ratios of BrS case-control enrichment and penetrance for BrS were calculated from variant frequencies in the BrS cohort and in gnomAD. RESULTS: Most variants (146/252) were functionally abnormal (Z ≤ -2), with 100 having severe loss-of-function (Z ≤ -4). Functional evidence enabled the reclassification of 110 of 225 VUS; 104 to likely pathogenic and 6 to likely benign. SCN5A variants with loss-of-function were mainly localized to the transmembrane domains, especially the regions comprising the central pore. SCN5A variant penetrance was proportional to the severity of loss-of-function; variants with Z ≤ -6 had penetrance of 24.5% (15.9%-37.7% CI) and an odds ratio of 501 for BrS. CONCLUSIONS: This cohort-scale APC dataset stratifies SCN5A variants found in BrS patients into normal function 'bystander' variants that have a low risk of BrS and loss-of-function variants that have a high risk for BrS. Functional data can be integrated with other criteria to reclassify a substantial fraction of VUS. The dataset helps clarify the SCN5A-BrS relationship and will improve the diagnosis and clinical management of BrS probands and their families.

Humans↗