Subject-Specific Activation of Central Respiratory Centers during Breath-Holding Functional Magnetic Resonance Imaging.

Background: Voluntary breath-holding (BH) triggers responses from central neural control and respiratory centers in order to restore breathing. Such responses can be observed using functional MRI (fMRI).

Objectives: We used this paradigm in healthy volunteers with the view to develop a biomarker that could be used to investigate disorders of the central control of breathing at the individual patient level.

Involvement of the posterior tool processing network during explicit retrieval of action tool and semantic tool knowledge: an fMRI study.

Our ability to understand how to interact with familiar objects is supported by conceptual tool knowledge. Conceptual tool knowledge includes action tool and semantic tool knowledge which are supported by the ventro-dorsal and the ventral pathways, respectively. This apparent functional segregation has been recently called into question.

Cortical inflammation and brain signs of high-risk atherosclerosis in a non-human primate model.

Atherosclerosis is a chronic systemic inflammatory disease, inducing cardiovascular and cerebrovascular acute events. A role of neuroinflammation is suspected, but not yet investigated in the gyrencephalic brain and the related activity at blood-brain interfaces is unknown. A non-human primate model of advanced atherosclerosis was first established using longitudinal blood samples, multimodal imaging and gene analysis in aged animals.

Neural correlates of verbal working memory in children with epilepsy with centro-temporal spikes.

Background: Previous functional magnetic resonance imaging (fMRI) studies have identified brain systems underlying different components of working memory (WM) in healthy subjects. The aim of this study was to compare the functional integrity of these neural networks in children with self-limited childhood epilepsy with centro-temporal spikes (ECTS) as compared to healthy controls, using a verbal working memory task (WMT).

Methods: Functional MRI of WM in seventeen 6-to-13 year-old children, diagnosed with ECTS, and 17 sex- and age-matched healthy controls were conducted at 3 T.

Social cognition, behaviour and therapy adherence in frontal lobe epilepsy: a study combining neuroeconomic and neuropsychological methods.

Social behaviour of healthy humans and its neural correlates have been extensively studied in social neuroscience and neuroeconomics. Whereas it is well established that several types of epilepsies, such as frontal lobe epilepsy, lead to social cognitive impairments, experimental evidence on how these translate into behavioural symptoms is scarce. Furthermore, it is unclear whether social cognitive or behavioural disturbances have an impact on therapy adherence, which is critical for effective disease management, but generally low in these patients.

Early limbic microstructural alterations in apathy and depression in de novo Parkinson's disease.

Background: Whether structural alterations underpin apathy and depression in de novo parkinsonian patients is unknown. The objectives of this study were to investigate whether apathy and depression in de novo parkinsonian patients are related to structural alterations and how structural abnormalities relate to serotonergic or dopaminergic dysfunction.

Methods: We compared the morphological and microstructural architecture in gray matter using voxel-based morphometry and diffusion tensor imaging coupled with white matter tract-based spatial statistics in a multimodal imaging case-control study enrolling 14 apathetic and 13 nonapathetic patients with de novo Parkinson's disease and 15 age-matched healthy controls, paired with PET imaging of the presynaptic dopaminergic and serotonergic systems.

Basal ganglia involvement in patients: The reason for patients very specific grasping?

The () gene was identified in 2002 as responsible for XLAG syndrome, a lissencephaly characterized by an almost complete absence of cortical GABAergic interneurons, and for milder forms of X-linked Intellectual Disability (ID) without apparent brain abnormalities. The most frequent mutation found in the gene, a duplication of 24 base pairs (c.429_452dup24) in exon 2, results in a recognizable syndrome in which patients present ID without primary motor impairment, but with a very specific upper limb distal motor apraxia associated with a pathognomonic hand-grip, described as developmental Limb Kinetic Apraxia (LKA).

Lesions in deep gray nuclei after severe traumatic brain injury predict neurologic outcome.

Purpose: This study evaluates the correlation between injuries to deep gray matter nuclei, as quantitated by lesions in these nuclei on MR T2 Fast Spin Echo (T2 FSE) images, with 6-month neurological outcome after severe traumatic brain injury (TBI).

Materials And Methods: Ninety-five patients (80 males, mean age = 36.7y) with severe TBI were prospectively enrolled.

Behavioral and fMRI responses to fearful faces are altered in benign childhood epilepsy with centrotemporal spikes (BCECTS).

Objective: We hypothesized that children with benign childhood epilepsy with centrotemporal spikes (BCECTS) might have altered social cognitive skills and underlying neural networks.

Methods: We studied 13 patients with BCECTS and 11 age-matched controls using event-related functional magnetic resonance imaging (fMRI) with an emotional discrimination task consisting of viewing happy, fearful, scrambled, and neutral faces. Behavioral performance measured during the task was correlated with clinical variables and behavioral ratings.

Studying the neural bases of prism adaptation using fMRI: A technical and design challenge.

Prism adaptation induces rapid recalibration of visuomotor coordination. The neural mechanisms of prism adaptation have come under scrutiny since the observations that the technique can alleviate hemispatial neglect following stroke, and can alter spatial cognition in healthy controls. Relative to non-imaging behavioral studies, fMRI investigations of prism adaptation face several challenges arising from the confined physical environment of the scanner and the supine position of the participants.

Intracellular Phosphate Dynamics in Muscle Measured by Magnetic Resonance Spectroscopy during Hemodialysis.

Of the 600-700 mg inorganic phosphate (Pi) removed during a 4-hour hemodialysis session, a maximum of 10% may be extracted from the extracellular space. The origin of the other 90% of removed phosphate is unknown. This study tested the hypothesis that the main source of phosphate removed during hemodialysis is the intracellular compartment.

A phantom and animal study of temperature changes during fMRI with intracerebral depth electrodes.

Background: MRI is routinely used in patients undergoing intracerebral electroencephalography (icEEG) in order to precisely locate the position of intracerebral electrodes. In contrast, fMRI has been considered unsafe due to suspected greater risk of radiofrequency-induced (RF) tissue heating at the vicinity of intracerebral electrodes. We determined the possible temperature change at the tip of such electrodes during fMRI sessions in phantom and animals.

Multimodal convergence within the intraparietal sulcus of the macaque monkey.

The parietal cortex is highly multimodal and plays a key role in the processing of objects and actions in space, both in human and nonhuman primates. Despite the accumulated knowledge in both species, we lack the following: (1) a general description of the multisensory convergence in this cortical region to situate sparser lesion and electrophysiological recording studies; and (2) a way to compare and extrapolate monkey data to human results. Here, we use functional magnetic resonance imaging (fMRI) in the monkey to provide a bridge between human and monkey studies.

Assessment of white matter injury and outcome in severe brain trauma: a prospective multicenter cohort.

Background: Existing methods to predict recovery after severe traumatic brain injury lack accuracy. The aim of this study is to determine the prognostic value of quantitative diffusion tensor imaging (DTI).

Methods: In a multicenter study, the authors prospectively enrolled 105 patients who remained comatose at least 7 days after traumatic brain injury.

Correlation of diffusion and metabolic alterations in different clinical forms of multiple sclerosis.

Diffusion tensor imaging (DTI) and MR spectroscopic imaging (MRSI) provide greater sensitivity than conventional MRI to detect diffuse alterations in normal appearing white matter (NAWM) of Multiple Sclerosis (MS) patients with different clinical forms. Therefore, the goal of this study is to combine DTI and MRSI measurements to analyze the relation between diffusion and metabolic markers, T2-weighted lesion load (T2-LL) and the patients clinical status. The sensitivity and specificity of both methods were then compared in terms of MS clinical forms differentiation.

Implementation of an absolute brain 1H-MRS quantification method to assess different tissue alterations in multiple sclerosis.

Magnetic resonance spectroscopy has emerged as a sensitive modality to detect early and diffuse alterations in multiple sclerosis. Recently, the hypothesis of neurodegenerative pathogenesis has highlightened the interest for measurement of metabolites concentrations, to gain specificity, in a large brain volume encompassing different tissue alterations. Therefore, we proposed in this paper the implementation of an absolute quantification method based on localized spectroscopy at short (30 ms) and long (135 ms) echo time of a volume including normal appearing white matter, cortical gray matter, and lesions.

Thalamus abnormalities during working memory in schizophrenia. An fMRI study.

We aimed to identify and compare cerebral activations in schizophrenia patients and controls during a working memory (WM) task at the same performance level for both a verbal and a spatial task. Whereas the performances of the patients (n=22) and controls (n=15) were similar, cerebral activations were significantly increased in the patients, particularly in the thalamus/basal ganglia for the two tasks and in regions of the prefrontal cortex and the cerebellum for the spatial task only. Our results suggest that stronger activations of deep brain structures in patients may be the result from a compensating mechanism for WM difficulties.

Rapid-clearance iron nanoparticles for inflammation imaging of atherosclerotic plaque: initial experience in animal model.

Purpose: To evaluate the use of a recently developed fast-clearing ultrasmall superparamagnetic iron oxide (USPIO) for detection of vascular inflammation in atherosclerotic plaque.

Materials And Methods: The study protocol was approved by the animal experimentation ethics committee. A recently introduced USPIO, P904, and a reference-standard USPIO, ferumoxtran-10, were tested in a rabbit model of induced aortic atherosclerosis.

The left ventral occipito-temporal response to words depends on language lateralization but not on visual familiarity.

The sensitivity of the left ventral occipito-temporal (vOT) cortex to visual word processing has triggered a considerable debate about the role of this region in reading. One popular view is that the left vOT underlies the perceptual expertise needed for rapid skilled reading. Because skilled reading breaks down when words are presented in a visually unfamiliar format, we tested this hypothesis by analyzing vOT responses to horizontally presented words (familiar format) and vertically presented words (unfamiliar format).

Chronic motor cortex stimulation for phantom limb pain: a functional magnetic resonance imaging study: technical case report.

Objective And Importance: Chronic motor cortex stimulation has provided satisfactory control of pain in patients with central or neuropathic trigeminal pain. We used this technique in a patient who experienced phantom limb pain. Functional magnetic resonance imaging (fMRI) was used to guide electrode placement and to assist in understanding the control mechanisms involved in phantom limb pain.

"Absolute" quantification in magnetic resonance spectroscopy: validation of a clinical protocol in multiple sclerosis.

MRS allows to measure cerebral metabolites, thus helping to characterize brain disease diagnosis and followup. Metabolite concentration quantification is usually based on metabolite ratio referring to creatine. If this metabolite concentration is supposed to be constant, it may vary in pathological processes.

Block of neural Kv1.1 potassium channels for neuroinflammatory disease therapy.

Objective: We asked whether blockade of voltage-gated K+ channel Kv1.1, whose altered axonal localization during myelin insult and remyelination may disturb nerve conduction, treats experimental autoimmune encephalomyelitis (EAE).

Methods: Electrophysiological, cell proliferation, cytokine secretion, immunohistochemical, clinical, brain magnetic resonance imaging, and spectroscopy studies assessed the effects of a selective blocker of Kv1.

Functional magnetic resonance imaging and cognition at the very early stage of MS.

Dysfunction of high controlled information processing is present in patients with multiple sclerosis (MS) right at the beginning of the disease. One hypothesis is that disruption of communication inside large-scale cortical networks, occurring as a consequence of white matter damage, may constitute the anatomical substrate of cognitive impairment at the very early stage of MS. Disturbance of interregional synchronization might be the main pathogenic factor in controlled information processing deficiency in early MS.

Imaging experimental cerebral malaria in vivo: significant role of ischemic brain edema.

The first in vivo magnetic resonance study of experimental cerebral malaria is presented. Cerebral involvement is a lethal complication of malaria. To explore the brain of susceptible mice infected with Plasmodium berghei ANKA, multimodal magnetic resonance techniques were applied (imaging, diffusion, perfusion, angiography, spectroscopy).

Local tissue damage assessed with statistical mapping analysis of brain magnetization transfer ratio: relationship with functional status of patients in the earliest stage of multiple sclerosis.

Background And Purpose: In the early stage of Multiple Sclerosis (MS), conventional MR imaging parameters such as T2 lesion load fail to explain the clinical status of patients. In the present work, we aimed to determine the ability of magnification transfer imaging to better reflect the relationship between local tissue damage and functional status of MS patients.

Methods: We performed a comparative statistical mapping analysis on brain tissue magnetization transfer ratio (MTR) data measured in 18 patients with clinically isolated syndrome suggestive of MS (CISSMS) and 18 matched control subjects.