Measuring Salivary Cortisol to Assess the Effect of Natural Environments on Stress Level in Acute Patients With Severe Brain Injuries: An Exploratory Study.

Background: Salivary cortisol is a safe and non-invasive measure of hypothalamic-pituitary-adrenal axis function and is used as a biomarker of the human stress response. Natural environments are recognized to contribute to help reduce the effect of stress.

Objective: To determine the feasibility of a salivary cortisol collection protocol for acute severely brain-injured patients, and to explore the influence of exposure to natural settings on salivary cortisol concentration as an index of stress level.

Increased delta power as a scalp marker of epileptic activity: a simultaneous scalp and intracranial electroencephalography study.

Background And Purpose: The purpose was to evaluate whether intracranial interictal epileptiform discharges (IEDs) that are not visible on the scalp are associated with changes in the frequency spectrum on scalp electroencephalograms (EEGs).

Methods: Simultaneous scalp high-density EEG and intracranial EEG recordings were recorded in nine patients undergoing pre-surgical invasive recordings for pharmaco-resistant temporal lobe epilepsy. Epochs with hippocampal IED visible on intracranial EEG (ic-IED) but not on scalp EEG were selected, as well as control epochs without ic-IED.

Disentangling the percepts of illusory movement and sensory stimulation during tendon vibration in the EEG.

Mechanical vibration of muscle tendons in specific frequencies - termed functional proprioceptive stimulation (FPS) - has the ability to induce the illusion of a movement which is congruent with a lengthening of the vibrated tendon and muscle. The majority of previous reports of the brain correlates of this illusion are based on functional neuroimaging. Contrary to the electroencephalogram (EEG) however, such technologies are not suitable for bedside or ambulant use.

Gradient of electro-convulsive therapy's antidepressant effects along the longitudinal hippocampal axis.

Despite decades of successful treatment of therapy-resistant depression and major scientific advances in the field, our knowledge about electro-convulsive therapy's (ECT) mechanisms of action is still scarce. Building on strong empirical evidence for ECT-induced hippocampus anatomy changes, we sought to test the hypothesis that ECT has a differential impact along the hippocampus longitudinal axis. We acquired behavioural and brain anatomy magnetic resonance imaging (MRI) data in patients with depressive episode undergoing ECT (n = 9) or pharmacotherapy (n = 24) and healthy controls (n = 30) at two time points 3 months apart.

Dopaminergic modulation of motor network compensatory mechanisms in Parkinson's disease.

The dopaminergic system has a unique gating function in the initiation and execution of movements. When the interhemispheric imbalance of dopamine inherent to the healthy brain is disrupted, as in Parkinson's disease (PD), compensatory mechanisms act to stave off behavioral changes. It has been proposed that two such compensatory mechanisms may be (a) a decrease in motor lateralization, observed in drug-naïve PD patients and (b) reduced inhibition - increased facilitation.

Spatial Resolution and Imaging Encoding fMRI Settings for Optimal Cortical and Subcortical Motor Somatotopy in the Human Brain.

There is much controversy about the optimal trade-off between blood-oxygen-level-dependent (BOLD) sensitivity and spatial precision in experiments on brain's topology properties using functional magnetic resonance imaging (fMRI). The sparse empirical evidence and regional specificity of these interactions pose a practical burden for the choice of imaging protocol parameters. Here, we test in a motor somatotopy experiment the impact of fMRI spatial resolution on differentiation between body part representations in cortex and subcortical structures.

Isothermal microcalorimetry, a tool for probing SWNT bundles.

The bundling state of several dry single-walled carbon nanotube (SWNT) samples is compared using isothermal microcalorimetry (IMC). So as to get different dry samples with various bundling states, the pristine SWNTs were pretreated with a solution of an aromatic amphiphile with or without sonication, washed and dried before being studied by IMC. The bundling state of the different SWNT samples, which was first analyzed by TEM, was then correlated to the obtained IMC data thanks to the interpretation of the observed energy transfer phenomena.

Axially chiral facial amphiphiles with a dihydronaphthopentaphene structure as molecular tweezers for SWNTs.

Syntheses of chiral 6,15-dihydronaphtho[2,3-c]pentaphene derivatives of opposite configurations are reported. Starting from anthracene, the strategy involves two key steps: a Diels-Alder reaction on a prochiral dianthraquinone, and an enantiomeric resolution using (-)-menthol. The final molecules exhibit very strong optical activity, as shown by their circular dichroism spectra, and are examples of chiral facial amphiphiles.

Supramolecular discrimination of carbon nanotubes according to their helicity.

Adsorption of specifically designed and geometrically constrained polyaromatic amphiphiles on single-walled carbon nanotubes (SWNTs) was found to be selective of the nanotube helicity angle. Starting from the same SWNT mixture, photoluminescence and resonant Raman spectroscopies show that a pentacenic-based amphiphile leads to the solubilization of armchair SWNTs and that a quaterrylene-based amphiphile leads to the solubilization of zigzag SWNTs. The results were predicted by the design of the two amphiphiles and are consistent with a supramolecular recognition of the nanotube graphene-type atomic structure by the aromatic part of the molecules through optimized pi-pi-stacking interactions.