Linking structural and functional changes during healthy aging and semantic dementia using multilayer brain network analysis.

Healthy aging is characterized by frontal and diffuse brain changes, while certain age-related pathologies such as semantic dementia will be associated with more focal brain lesions, particularly in the temporo-parietal regions. These changes in structural integrity could influence functional brain networks. Here we use multilayer brain network analysis on structural (DWI) and functional (fMRI) data in younger and older healthy individuals and patients with semantic dementia.

Contribution of [F]FET PET in the Management of Gliomas, from Diagnosis to Follow-Up: A Review.

Gliomas, the most common type of primary malignant brain tumors in adults, pose significant challenges in diagnosis and management due to their heterogeneity and potential aggressiveness. This review evaluates the utility of O-(2-[F]fluoroethyl)-L-tyrosine ([F]FET) positron emission tomography (PET), a promising imaging modality, to enhance the clinical management of gliomas. We reviewed 82 studies involving 4657 patients, focusing on the application of [F]FET in several key areas: diagnosis, grading, identification of IDH status and presence of oligodendroglial component, guided resection or biopsy, detection of residual tumor, guided radiotherapy, detection of malignant transformation in low-grade glioma, differentiation of recurrence versus treatment-related changes and prognostic factors, and treatment response evaluation.

The multiscale topological organization of the functional brain network in adolescent PTSD.

The experience of an extremely aversive event can produce enduring deleterious behavioral, and neural consequences, among which posttraumatic stress disorder (PTSD) is a representative example. Although adolescence is a period of great exposure to potentially traumatic events, the effects of trauma during adolescence remain understudied in clinical neuroscience. In this exploratory work, we aim to study the whole-cortex functional organization of 14 adolescents with PTSD using a data-driven method tailored to our population of interest.

High Pressure Promotes Binding of the Allosteric Inhibitor Zn-Cyclen in Crystals of Activated H-Ras.

In this work, we experimentally investigate the potency of high pressure to drive a protein toward an excited state where an inhibitor targeted for this state can bind. Ras proteins are small GTPases cycling between active GTP-bound and inactive GDP-bound states. Various states of GTP-bound Ras in active conformation coexist in solution, amongst them, state 2 which binds to effectors, and state 1, weakly populated at ambient conditions, which has a low affinity for effectors.

Linking structural and functional changes during aging using multilayer brain network analysis.

Brain structure and function are intimately linked, however this association remains poorly understood and the complexity of this relationship has remained understudied. Healthy aging is characterised by heterogenous levels of structural integrity changes that influence functional network dynamics. Here, we use the multilayer brain network analysis on structural (diffusion weighted imaging) and functional (magnetoencephalography) data from the Cam-CAN database.

[Memory tests].

MEMORY TESTS. Memory tests used in clinical practice mainly concern anterograde memory through the evaluation of learning, short- or long-term retention, and retrieval of information. They use different types of material (verbal or visual) and different tasks to assess the integrity of the different memory processes: encoding, storage and retrieval.

[Neuropsychology of memory].

NEUROPSYCHOLOGY OF MEMORY. In neuropsychology, memory is shown as a complex function composed of several memory systems. Five memory systems are proposed: working memory (or short term memory), episodic memory, semantic memory, perceptive memory, and procedural memory.

Container-content interactions with radiopharmaceuticals: Seeing is believing.

This perspective article addresses the critical issue of container-content interactions in the administration of intravenous medications, with a focus on radiopharmaceuticals used in nuclear medicine. Medication administration errors pose a significant challenge to patient safety. The "five rights" framework-ensuring the right patient, drug, time, dose, and route-serves as a cornerstone for safe drug administration.

Mathematical modeling of human memory.

The mathematical study of human memory is still an open challenge. Cognitive psychology and neuroscience have given a big contribution to understand how the human memory is structured and works. Cognitive psychologists developed experimental paradigms, conceived quantitative measures of performance in memory tasks for both healthy people and patients with memory disorders, but in terms of mathematical modeling human memory there is still a lot to do.

Exploring the structural dynamics of proteins by pressure perturbation using macromolecular crystallography.

High pressure is a convenient thermodynamic parameter to probe the dynamics of proteins as it is intimately related to volume which is essential for protein function. To be biologically active, a protein fluctuates between different substates. Pressure perturbation can promote some hidden substates by modifying the population between them.

Nonlinear changes in delayed functional network topology in Alzheimer's disease: relationship with amyloid and tau pathology.

Background: Alzheimer's disease is a neurodegenerative disorder associated with the abnormal deposition of pathological processes, such as amyloid-ß and tau, which produces nonlinear changes in the functional connectivity patterns between different brain regions across the Alzheimer's disease continuum. However, the mechanisms underlying these nonlinear changes remain largely unknown. Here, we address this question using a novel method based on temporal or delayed correlations and calculate new whole-brain functional networks to tackle these mechanisms.

Safety and Therapeutic Optimization of Lutetium-177 Based Radiopharmaceuticals.

Peptide receptor radionuclide therapy (PRRT) using Lutetium-177 (Lu) based radiopharmaceuticals has emerged as a therapeutic area in the field of nuclear medicine and oncology, allowing for personalized medicine. Since the first market authorization in 2018 of [¹⁷⁷Lu]Lu-DOTATATE (Lutathera®) targeting somatostatin receptor type 2 in the treatment of gastroenteropancreatic neuroendocrine tumors, intensive research has led to transfer innovative Lu containing pharmaceuticals to the clinic. Recently, a second market authorization in the field was obtained for [¹⁷⁷Lu]Lu-PSMA-617 (Pluvicto®) in the treatment of prostate cancer.

Sensogenomics of music and Alzheimer's disease: An interdisciplinary view from neuroscience, transcriptomics, and epigenomics.

Introduction: The relationship between music and Alzheimer's disease (AD) has been approached by different disciplines, but most of our outstanding comes from neuroscience.

Methods: First, we systematically reviewed the state-of-the-art of neuroscience and cognitive sciences research on music and AD (>100 studies), and the progress made on the therapeutic impact of music stimuli in memory. Next, we meta-analyzed transcriptomic and epigenomic data of AD patients to search for commonalities with genes and pathways previously connected to music in genome association, epigenetic, and gene expression studies.

Optimised quality control method for determination of the radiochemical purity of [Tc]Tc-mebrofenin and [Tc]Tc-etifenin in a clinical context.

Objectives: In the context of a supply disruption of mebrofenin (Cholediam)-based kits for radiolabelling with technetium-99m [Tc], the medicine agencies allowed the importation of a back-up radiopharmaceutical diagnostic agent, etifenin (Techida), to ensure continuous management of patients with hepatobiliary disorders in nuclear medicine departments. There are still issues regarding the measurement of radiochemical purity (RCP) with these kits based on the European Pharmacopoeia and the Summary of Product Characteristics (SPC). This study aims to identify and to optimise, in a clinical context, the most suitable thin layer chromatography (TLC) method for the determination of the RCP in terms of speed of response and reliability for [Tc]Tc-mebrofenin and [Tc]Tc-etifenin.

Attentional capture mediates the emergence and suppression of intrusive memories.

Intrusive memories hijack consciousness and their control may lead to forgetting. However, the contribution of reflexive attention to qualifying a memory signal as interfering is unknown. We used machine learning to decode the brain's electrical activity and pinpoint the otherwise hidden emergence of intrusive memories reported during a memory suppression task.

Impact of disposable syringes type choice on myocardial perfusion imaging procedures with [Tc]Tc-tetrofosmin.

Background: Residual activity in dispensing syringes is a problem that has been sporadically reported with various radiopharmaceuticals. Studies with [Tc]Tc-tetrofosmin are non-consistent so far. The aim was to quantify the residual activity of [Tc]Tc-tetrofosmin in different syringes in a clinical setting and to assess its impact on the clinical imaging procedure.

Toward new memory sciences: The Programme 13-Novembre.

Studies devoted to individual and collective memory have evolved in a compartmentalized way for more than a century. We recall the most emblematic historical works of two distinct visions of memory: those of the experimental psychologist Hermann Ebbinghaus who measured memory, on himself, from lists of meaningless syllables, and those of the sociologist Maurice Halbwachs for whom any act of memory is a social act. Since the beginning of the years 2000, the social turn in life sciences and, more rarely, the opening up of sociologists and historians to the life sciences have tended to bring these hitherto compartmentalized currents together.

Functional connectivity of the medial prefrontal cortex related to mindreading abilities.

The medial prefrontal cortex is a key region of mindreading belonging to the mentalizing system, a set of brain areas underlying mental state inference based on reasoning on social concepts. The aim of this study was to characterize the functional connectivity between regions involved in mindreading and to highlight the processes it underpins, focusing on the dorsal and ventral parts of the medial prefrontal cortex. We analyzed resting-state functional magnetic resonance imaging of 56 healthy volunteers, to study the relationship between mindreading abilities and functional connectivity of the medial prefrontal cortex.

Connectivity dynamics and cognitive variability during aging.

Aging is associated with cognitive changes, with strong variations across individuals. One way to characterize this individual variability is to use techniques such as magnetoencephalography (MEG) to measure the dynamics of neural synchronization between brain regions, and the variability of this connectivity over time. Indeed, few studies have focused on fluctuations in the dynamics of brain networks over time and their evolution with age.

M/EEG Dynamics Underlying Reserve, Resilience, and Maintenance in Aging: A Review.

Cognitive reserve and resilience refer to the set of processes allowing the preservation of cognitive performance in the presence of structural and functional brain changes. Investigations of these concepts have provided unique insights into the heterogeneity of cognitive and brain changes associated with aging. Previous work mainly relied on methods benefiting from a high spatial precision but a low temporal resolution, and thus the temporal brain dynamics underlying these concepts remains poorly known.

Equilibria between conformational states of the Ras oncogene protein revealed by high pressure crystallography.

In this work, we experimentally investigate the allosteric transitions between conformational states on the Ras oncogene protein using high pressure crystallography. Ras protein is a small GTPase involved in central regulatory processes occurring in multiple conformational states. Ras acts as a molecular switch between active GTP-bound, and inactive GDP-bound states, controlling essential signal transduction pathways.

Comparative study of the effects of high hydrostatic pressure per se and high argon pressure on urate oxidase ligand stabilization.

The stability of the tetrameric enzyme urate oxidase in complex with excess of 8-azaxanthine was investigated either under high hydrostatic pressure per se or under a high pressure of argon. The active site is located at the interface of two subunits, and the catalytic activity is directly related to the integrity of the tetramer. This study demonstrates that applying pressure to a protein-ligand complex drives the thermodynamic equilibrium towards ligand saturation of the complex, revealing a new binding site.