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The noradrenergic locus coeruleus (LC) is a controller of brain and behavioral states. Activating LC neurons en masse by electrical or optogenetic stimulation promotes a stereotypical “activated” cortical state of high-frequency oscillations. However, it has been recently reported that spontaneous activity of LC cell pairs has sparse yet structured time-averaged cross-correlations, which is unlike the highly synchronous neuronal activity evoked by stimulation. Therefore, LC population activity could consist of distinct multicell ensembles each with unique temporal evolution of activity. We used nonnegative matrix factorization (NMF) to analyze large populations of simultaneously recorded LC single units in the rat LC. NMF identified ensembles of spontaneously coactive LC neurons and their activation time courses. Since LC neurons selectively project to specific forebrain regions, we hypothesized that distinct ensembles activate during different cortical states. To test this hypothesis, we calculated band-limited power and spectrograms of local field potentials in cortical area 24a aligned to spontaneous activations of distinct LC ensembles. A diversity of state modulations occurred around activation of different LC ensembles, including a typical activated state with increased high-frequency power as well as other states including decreased high-frequency power. Thus—in contrast to the stereotypical activated brain state evoked by en masse LC stimulation—spontaneous activation of distinct LC ensembles is associated with a multitude of cortical states.
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http://dx.doi.org/10.1073/pnas.2116507119 | DOI Listing |
Biomolecules
January 2025
Regenerative Therapy Unit, Lausanne University Hospital, University of Lausanne, CH-1066 Epalinges, Switzerland.
Polydeoxyribonucleotides (PDRNs) and polynucleotides (PNs) are similar DNA-derived biopolymers that have garnered significant scientific attention since the 1990s for their potential applications in wound healing and skin rejuvenation. These biopolymers exhibit a broad molecular weight (MW) range, typically spanning from 50 to 1500 kDa. However, recent studies have expanded this range to encompass fragments as small as 1 kDa and as large as 10,000 kDa.
View Article and Find Full Text PDFDiagnostics (Basel)
January 2025
Department of Digital Forensics Engineering, Technology Faculty, Firat University, Elazig 23119, Turkey.
Electroencephalography (EEG) signal-based machine learning models are among the most cost-effective methods for information retrieval. In this context, we aimed to investigate the cortical activities of psychotic criminal subjects by deploying an explainable feature engineering (XFE) model using an EEG psychotic criminal dataset. In this study, a new EEG psychotic criminal dataset was curated, containing EEG signals from psychotic criminal and control groups.
View Article and Find Full Text PDFJ Affect Disord
January 2025
Department of Global Public Health, Karolinska Institutet, 171 77, Stockholm, Sweden.
Physical exercise (PE) as antidepressive intervention is a promising alternative, as shown by multiple meta-analyses. However, there is no consensus regarding optimal intensity and duration of exercise, and there are no objective criteria available for personalized indication of treatment. The aims of this study were (1) to evaluate whether individual activity patterns before intervention can predict the response to treatment; and (2) to evaluate whether the patient outcome can be improved by using prior information on treatment efficacy at individual level.
View Article and Find Full Text PDFdescribes the ability of biological macromolecules to transmit signals spatially through the molecule from an site – a site that is distinct from binding sites of primary, endogenous ligands – to the functional or active site. This review starts with a historical overview and a description of the classical example of allostery – hemoglobin – and other well-known examples (aspartate transcarbamoylase, Lac repressor, kinases, G-protein-coupled receptors, adenosine triphosphate synthase, and chaperonin). We then discuss fringe examples of allostery, including intrinsically disordered proteins and inter-enzyme allostery, and the influence of dynamics, entropy, and conformational ensembles and landscapes on allosteric mechanisms, to capture the essence of the field.
View Article and Find Full Text PDFNanoscale Adv
January 2025
Department of Chemical Sciences, University of Padova via Marzolo 1 35131 Padova Italy
In this study, we used two-dimensional electronic spectroscopy to examine the early femtosecond dynamics of suspensions of colloidal gold nanorods with different aspect ratios. In all samples, the signal distribution in the 2D maps at this timescale shows a distinctive dispersive behavior, which can be explained by the interference between the exciting field and the field produced on the nanoparticle's surface by the collective motion of electrons when the plasmon is excited. Studying this interference effect, which is active only until the plasmon has been dephased, allows for a direct estimation of the dephasing time of the plasmon of an ensemble of colloidal particles.
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