Preclinical detection of Alzheimer's disease pathology using conceptual discrimination abilities.

Background: Performance on the Conceptual Matching Task (CMT), a measure of discrimination between conceptually confusable items, has been suggested as a cognitive marker of rhinal cortex atrophy, one of the first brain regions affected by Alzheimer's disease (AD) pathology.

Objectives: We aimed to determine whether CMT can detect preclinical AD, and whether CMT performance is related to regional deposition of tau protein or other AD-associated lesions including amyloid (Aβ) accumulation and white matter hyperintensities (WMH).

Design, Setting And Participants: This cross-sectional study include 101 participants from the UCL2016-121 cohorts in Brussels, Belgium, classified as 56 Aβ-negative cognitively unimpaired (Aβ-CU), 25 Aβ-positive CU (Aβ+CU, preclinical AD), and 20 Aβ-positive mildly cognitively impaired (Aβ+MCI, prodromal AD) individuals.

Fronto-motor circuits linked to effort-based decision-making and apathy in healthy subjects.

Apathy is marked by disruptions in effort-based decision-making for rewards and alterations in fronto-basal ganglia (BG) circuits. While changes in primary motor cortex (M1) activity during effort and reward valuation have been reported, prior work on apathy and effort-based decision-making has overlooked the connections between fronto-BG structures and M1. Here, we addressed this gap by investigating structural and effective connectivity within fronto-M1, fronto-BG-M1, and intra-M1 circuits in 45 healthy participants using tractography and paired-pulse transcranial magnetic stimulation.

Odor increases synchronization of brain activity when watching emotional movies.

Objective: Recent functional magnetic resonance imaging (fMRI) studies have shown that interpersonal synchronization of brain activity can be measured between people sharing similar emotional, narrative, or attentional states. There is evidence that odors can modulate the activity of brain regions involved in memory, emotion and social cognition, suggesting a link between shared olfactory experiences and synchronized brain activity in social contexts.

Method: We used fMRI to investigate the effects of a positively-valenced odor on inter-subject correlation (ISC) of brain activity in healthy volunteers watching movies.

Leveraging Swin Transformer for enhanced diagnosis of Alzheimer's disease using multi-shell diffusion MRI.

Objective: This study aims to support early diagnosis of Alzheimer's disease and detection of amyloid accumulation by leveraging the microstructural information available in multi-shell diffusion MRI (dMRI) data, using a vision transformer-based deep learning framework.

Methods: We present a classification pipeline that employs the Swin Transformer, a hierarchical vision transformer model, on multi-shell dMRI data for the classification of Alzheimer's disease and amyloid presence. Key metrics from DTI and NODDI were extracted and projected onto 2D planes to enable transfer learning with ImageNet-pretrained models.

Long-lasting effects of lavender exposure on brain resting-state networks in healthy women.

Introduction: Most brain imaging studies on olfaction focus on short-term odorant stimuli, with few examining long-lasting odor exposure or its after-effects. In this study, we utilized resting-state fMRI (rsfMRI) to investigate the effects of prolonged odor exposure to lavender on brain activity and whether these persist post-exposure.

Methods: Fourteen healthy women underwent two fMRI sessions, conducted one week apart, in a randomized order.

Entorhinal tau impairs short-term memory binding in preclinical Alzheimer's disease.

Objective: The entorhinal cortex (EC) is the first cortical region affected by tau pathology in Alzheimer's disease (AD), but its functions remain unclear. The EC is thought to support memory binding, which can be tested using the Visual Short-Term Memory Binding Test (VSTMBT). We aimed to test whether VSTMBT performance can identify individuals with preclinical AD before noticeable episodic memory impairment and whether these performances are related to amyloid (Aβ) pathology and/or EC tau burden.

Unfamiliar facial identity discrimination and recognition impairment in prodromal Alzheimer's disease: A behavioral pattern separation and completion study.

Background: Impairment of face identity recognition (FIR) in prodromal Alzheimer's disease (AD) is not clearly established, and the cognitive processes underpinning a potential FIR impairment remain elusive. The influential pattern separation (PS) and completion (PC) framework may offer a fascinating insight in this respect. Indeed, efficient FIR implies PS to encode facial identities in distinct memory representations, while PC is involved in matching the perceived facial patterns to these memory representations at retrieval.

Preoperative MRI, audiovisual speech perception, and mood are associated with cochlear implant outcomes in adults with postlingual deafness.

Acquired severe to profound hearing loss is an increasingly challenging problem of our aging population. Cochlear implantation (CI) is the gold standard treatment for this advanced form of sensory deprivation. Despite the overall satisfactory results of CI, a substantial number of patients show unsatisfactory outcomes.

Tau PET Imaging With [F]MK-6240: Limited Affinity for Primary Tauopathies and High Specificity for Alzheimer's Disease.

Introduction: Second-generation tau-PET tracers like [F]MK-6240 are increasingly used both for diagnosing and quantifying Alzheimer's Disease (AD) tauopathy. However, while [F]MK-6240 tau-PET has demonstrated excellent sensitivity for AD tauopathy, data assessing its specificity and binding in non-AD tauopathies are still scarce.

Methods: Participants were assigned to exclusive categorical diagnoses based on their amyloid (Aβ) and cognitive status.

Rotation errors in path integration are associated with Alzheimer's disease tau pathology: a cross-sectional study.

Background: Early Alzheimer's disease diagnosis is crucial for preventive therapy development. Standard neuropsychological evaluation does not identify clinically normal individuals with brain amyloidosis, the first stage of the pathology, defined as preclinical Alzheimer's disease. Spatial navigation assessment, in particular path integration, appears promising to detect preclinical symptoms, as the medial temporal lobe plays a key role in navigation and is the first cortical region affected by tau pathology.

Amyloid-PET imaging predicts functional decline in clinically normal individuals.

Background: There is good evidence that elevated amyloid-β (Aβ) positron emission tomography (PET) signal is associated with cognitive decline in clinically normal (CN) individuals. However, it is less well established whether there is an association between the Aβ burden and decline in daily living activities in this population. Moreover, Aβ-PET Centiloids (CL) thresholds that can optimally predict functional decline have not yet been established.

Locus coeruleus features are linked to vagus nerve stimulation response in drug-resistant epilepsy.

The locus coeruleus-norepinephrine system is thought to be involved in the clinical effects of vagus nerve stimulation. This system is known to prevent seizure development and induce long-term plastic changes, particularly with the release of norepinephrine in the hippocampus. However, the requisites to become responder to the therapy and the mechanisms of action are still under investigation.

Baby HABIT-ILE intervention: study protocol of a randomised controlled trial in infants aged 6-18 months with unilateral cerebral palsy.

Introduction: Research using animal models suggests that intensive motor skill training in infants under 2 years old with cerebral palsy (CP) may significantly reduce, or even prevent, maladaptive neuroplastic changes following brain injury. However, the effects of such interventions to tentatively prevent secondary neurological damages have never been assessed in infants with CP. This study aims to determine the effect of the baby Hand and Arm Bimanual Intensive Therapy Including Lower Extremities (baby HABIT-ILE) in infants with unilateral CP, compared with a control intervention.

Dexterity in the Acute Phase of Stroke: Impairments and Neural Substrates.

Background: Stroke can impair manual dexterity, leading to loss of independence following incomplete recovery. Enhancing our understanding of dexterity impairment may improve neurorehabilitation.

Objectives: The study aimed to measure dexterity components in acute stroke patients with and without hand motor deficits, compare them to those of healthy controls (HC), and to explore the neural substrates involved in specific components of dexterity.

Corrigendum: Brain morphological modifications in congenital and acquired auditory deprivation: a systematic review and coordinate-based meta-analysis.

[This corrects the article DOI: 10.3389/fnins.2022.

The spatial extent of tauopathy on [F]MK-6240 tau PET shows stronger association with cognitive performances than the standard uptake value ratio in Alzheimer's disease.

Purpose: [F]MK-6240, a second-generation tau PET tracer, is increasingly used for the detection and the quantification of in vivo cerebral tauopathy in Alzheimer's disease (AD). Given that neurological symptoms are better explained by the topography rather than by the nature of brain lesions, our study aimed to evaluate whether cognitive impairment would be more closely associated with the spatial extent than with the intensity of tau-PET signal, as measured by the standard uptake value ratio (SUVr).

Methods: [F]MK6240 tau-PET data from 82 participants in the AD spectrum were quantified in three different brain regions (Braak ≤ 2, Braak ≤ 4, and Braak ≤ 6) using SUVr and the extent of tauopathy (EOT, percentage of voxels with SUVr ≥ 1.

Suspecting Non-Alzheimer's Pathologies and Mixed Pathologies: A Comparative Study Between Brain Metabolism and Tau Images.

Background: Alzheimer's disease (AD) pathology can be disclosed in vivo using amyloid and tau imaging, unlike non-AD neuropathologies for which no specific markers exist.

Objective: We aimed to compare brain hypometabolism and tauopathy to unveil non-AD pathologies.

Methods: Sixty-one patients presenting cognitive complaints (age 48-90), including 32 with positive AD biomarkers (52%), performed [18F]-Fluorodeoxyglucose (FDG)-PET (brain metabolism) and [18F]-MK-6240-PET (tau).

Connecting the dots: harnessing dual-site transcranial magnetic stimulation to quantify the causal influence of medial frontal areas on the motor cortex.

Dual-site transcranial magnetic stimulation has been widely employed to investigate the influence of cortical structures on the primary motor cortex. Here, we leveraged this technique to probe the causal influence of two key areas of the medial frontal cortex, namely the supplementary motor area and the medial orbitofrontal cortex, on primary motor cortex. We show that supplementary motor area stimulation facilitates primary motor cortex activity across short (6 and 8 ms) and long (12 ms) inter-stimulation intervals, putatively recruiting cortico-cortical and cortico-subcortico-cortical circuits, respectively.

Structural and functional characterization of the locus coeruleus in young and late middle-aged individuals.

Introduction: The brainstem locus coeruleus (LC) influences a broad range of brain processes, including cognition. The so-called LC contrast is an accepted marker of the integrity of the LC that consists of a local hyperintensity on specific Magnetic Resonance Imaging (MRI) structural images. The small size of the LC has, however, rendered its functional characterization difficult in humans, including in aging.

Unraveling multi-fixel microstructure with tractography and angular weighting.

Recent advances in MRI technology have enabled richer multi-shell sequences to be implemented in diffusion MRI, allowing the investigation of both the microscopic and macroscopic organization of the brain white matter and its complex network of neural fibers. The emergence of advanced diffusion models has enabled a more detailed analysis of brain microstructure by estimating the signal received from a voxel as the combination of responses from multiple fiber populations. However, disentangling the individual microstructural properties of different macroscopic white matter tracts where those pathways intersect remains a challenge.

Hand-Arm Bimanual Intensive Therapy Including Lower Extremities (HABIT-ILE) in adults with chronic stroke: protocol of a randomised controlled trial.

Introduction: Stroke causes multiple deficits including motor, sensitive and cognitive impairments, affecting also individual's social participation and independence in activities of daily living (ADL) impacting their quality of life. It has been widely recommended to use goal-oriented interventions with a high amount of task-specific repetitions. These interventions are generally focused only on the upper or lower extremities separately, despite the impairments are observed at the whole-body level and ADL are both frequently bimanual and may require moving around.

Brain structural changes in blindness: a systematic review and an anatomical likelihood estimation (ALE) meta-analysis.

In recent decades, numerous structural brain imaging studies investigated purported morphometric changes in early (EB) and late onset blindness (LB). The results of these studies have not yielded very consistent results, neither with respect to the type, nor to the anatomical locations of the brain morphometric alterations. To better characterize the effects of blindness on brain morphometry, we performed a systematic review and an Anatomical-Likelihood-Estimation (ALE) coordinate-based-meta-analysis of 65 eligible studies on brain structural changes in EB and LB, including 890 EB, 466 LB and 1257 sighted controls.