The thalamus has a key role in mediating cortical-subcortical interactions but is often neglected in neuroimaging studies, which mostly focus on changes in cortical structure and activity. One of the main reasons for the thalamus being overlooked is that the delineation of individual thalamic nuclei via neuroimaging remains controversial. Indeed, neuroimaging atlases vary substantially regarding which thalamic nuclei are included and how their delineations were established.
View Article and Find Full Text PDFTexture, a fundamental object attribute, is perceived through multisensory information including touch and auditory cues. Coherent perceptions may rely on shared texture representations across different senses in the brain. To test this hypothesis, we delivered haptic textures coupled with a sound synthesizer to generate real-time textural sounds.
View Article and Find Full Text PDFBackground: New diagnostic criteria of Progressive Supranuclear Palsy (PSP) have highlighted the interest of Eye Movement Records (EMR) at the early stage of the disease.
Objectives: To investigate the metabolic brain correlates of ocular motor dysfunction using [18F] Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) in early PSP.
Methods: Retrospective observational descriptive study on longitudinal data with patients who underwent EMR and FDG-PET at the stage of suggestive and possible PSP according to Movement Disorders Society criteria.
Background: APP duplication is a rare genetic cause of Alzheimer disease and cerebral amyloid angiopathy (CAA). We aimed to evaluate the phenotypes of APP duplications carriers.
Methods: Clinical, radiological, and neuropathological features of 43 APP duplication carriers from 24 French families were retrospectively analyzed, and MRI features and cerebrospinal fluid (CSF) biomarkers were compared to 40 APP-negative CAA controls.
Background: Prognosis of herpetic encephalitis remains severe, with a high proportion of deaths and sequelae. Its treatment is based on acyclovir, but the precise and most effective modalities of this treatment are not established. The objective of this study was to determine them.
View Article and Find Full Text PDFThe extrastriate body area (EBA) is a body-selective focal region located in the lateral occipito-temporal cortex that responds strongly to images of human bodies and body parts in comparison with other classes of stimuli. Whether EBA contributes also to the body recognition of self versus others remains in debate. We investigated whether EBA contributes to self-other distinction and whether there might be a hemispheric-side specificity to that contribution using double-pulse transcranial magnetic stimulation (TMS) in right-handed participants.
View Article and Find Full Text PDFGeneralization of sensorimotor adaptation across limbs, known as interlimb transfer, is a well-demonstrated phenomenon in humans, yet the underlying neural mechanisms remain unclear. Theoretical models suggest that interlimb transfer is mediated by interhemispheric transfer of information via the corpus callosum. We thus hypothesized that lesions of the corpus callosum, especially to its midbody connecting motor, supplementary motor, and premotor areas of the two cerebral hemispheres, would impair interlimb transfer of sensorimotor adaptation.
View Article and Find Full Text PDFSelectivity is the rule, rather than the exception, in neurodegenerative disease. A retired telephone operator carrying a C9orf72 expansion developed phonagnosia, a selective impairment of voice recognition, contrasting with intact person knowledge and recognition of faces, as a presenting sign of genetically confirmed fronto-temporal dementia. Since the dysfunction in this patient fell into his area of professional expertise, we discuss if overload in voice related neural networks might have caused failure propagating to connected nodes.
View Article and Find Full Text PDFThere is a growing interest in understanding functional brain decline with aging. The dataset provides raw anatomical and functional images recorded in a group of 20 young volunteers and in another group of 19 older volunteers during a 10-minute period of resting state followed by four consecutive task-related runs. During each task-related run, the participants were exposed to two types of sensory stimulation: a tactile stimulation consisting in a textured-disk rotation under the palm of their right hand or a muscle proprioceptive stimulation consisting in a mechanical vibration applied to the muscle tendon of their wrist abductor.
View Article and Find Full Text PDFObjective: Non-rapid eye movement (NREM) sleep is supposed to play a key role in long-term memory consolidation transferring information from hippocampus to neocortex. However, sleep also activates epileptic activities in medial temporal regions. This study investigated whether interictal hippocampal spikes during sleep would impair long-term memory consolidation.
View Article and Find Full Text PDFCorticobasal syndrome (CBS) is a neuropathologically heterogeneous entity. The use of cerebrospinal fluid and amyloid biomarkers enables detection of underlying Alzheimer's disease (AD) pathology. We thus compared clinical, eye movement, and 18FDG-PET imaging characteristics in CBS in two groups of patients divided according to their amyloid biomarkers profile.
View Article and Find Full Text PDFBackground: Neurodegeneration biomarkers are routinely used in the diagnosis of Alzheimer's disease (AD).
Objective: To evaluate the respective contributions of two neuroimaging biomarkers, structural MRI and 18FDG-PET, in the assessment of neurodegeneration in AD dementia.
Methods: Patients with mild AD dementia diagnosed based on clinical and cerebrospinal fluid criteria and cognitively healthy subjects, from the Marseille cohort ADAge with cognitive, structural MRI and 18FDG-PET assessments, were included.
To perceive self-hand movements, the central nervous system (CNS) relies on multiple sensory inputs mainly derived from vision, touch, and muscle proprioception. However, how and to what extent the CNS relies on these sensory systems to build kinesthetic percepts as the systems decline with age remain poorly understood. Illusory sensations of right hand rotation were induced by separately stimulating these three sensory modalities at two intensity levels.
View Article and Find Full Text PDFMemory complaints and deficits are common in patients with epilepsy, especially temporal lobe epilepsy (TLE), where memory-related brain structures are directly involved in the epileptic process. In recent years, substantial progress has been made in delineating memory impairment in TLE, challenging the traditional neuropsychological approach of the disorder. In particular, several lines of evidence have suggested that, beyond the apparent deficit demonstrable by standardized neuropsychological evaluations, TLE may also negatively interact with long-term memory, producing considerable loss of information of the patient's autobiographical history and an inability to maintain newly acquired information over a period of time.
View Article and Find Full Text PDFHearing loss is known to impact brain function. The aim of this study was to characterize cerebral metabolic Positron Emission Tomography (PET) changes in elderly patients fulfilling criteria for cochlear implant and investigate the impact of hearing loss on functional connectivity. Statistical Parametric Mapping-T-scores-maps comparisons of F-FDG-PET of 27 elderly patients fulfilling criteria for cochlear implant for hearing loss (best-aided speech intelligibility lower or equal to 50%) and 27 matched healthy subjects (p < 0.
View Article and Find Full Text PDFBackground: Amyloid protein precursor (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) mutations cause autosomal dominant forms of early-onset Alzheimer disease (AD-EOAD). Although these genes were identified in the 1990s, variant classification remains a challenge, highlighting the need to colligate mutations from large series.
Methods And Findings: We report here a novel update (2012-2016) of the genetic screening of the large AD-EOAD series ascertained across 28 French hospitals from 1993 onwards, bringing the total number of families with identified mutations to n = 170.
Neuroimaging biomarkers differ between patients with early-onset Alzheimer's disease (EOAD) and late-onset Alzheimer's disease (LOAD). Whether these changes reflect cognitive heterogeneity or differences in disease severity is still unknown. This study aimed at investigating changes in neuroimaging biomarkers, according to the age of onset of the disease, in mild amnestic Alzheimer's disease patients with positive amyloid biomarkers in cerebrospinal fluid.
View Article and Find Full Text PDFIntroduction: A classification framework for posterior cortical atrophy (PCA) is proposed to improve the uniformity of definition of the syndrome in a variety of research settings.
Methods: Consensus statements about PCA were developed through a detailed literature review, the formation of an international multidisciplinary working party which convened on four occasions, and a Web-based quantitative survey regarding symptom frequency and the conceptualization of PCA.
Results: A three-level classification framework for PCA is described comprising both syndrome- and disease-level descriptions.
Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are two atypical parkinsonian syndromes first described half a century ago. The spectrum of these conditions as well as, more generally, the concept of tauopathy have dramatically changed over the past decade and especially in recent years. In particular, clinicopathological correlations have led to the description of several subtypes of these diseases and the features they share with other neurodegenerative diseases.
View Article and Find Full Text PDFDiagonistic dyspraxia (DD) is by far the most spectacular manifestation reported by sufferers of acute corpus callosum (CC) injury (so-called "split-brain"). In this form of alien hand syndrome, one hand acts at cross purposes with the other "against the patient's will". Although recent models view DD as a disorder of motor control, there is still little information regarding its neural underpinnings, due to widespread connectivity changes produced by CC insult, and the obstacle that non-volitional movements represent for task-based functional neuroimaging studies.
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