Search results for "Homeostat"
showing 10 items of 38 documents
Transcranial direct current stimulation preconditioning modulates the effect of high-frequency repetitive transcranial magnetic stimulation in the hu…
2012
Experimental studies emphasize the importance of homeostatic plasticity as a mean of stabilizing the properties of neural circuits. In the present work we combined two techniques able to produce short-term (5-Hz repetitive transcranial magnetic stimulation, rTMS) and long-term (transcranial direct current stimulation, tDCS) effects on corticospinal excitability to evaluate whether and how the effects of 5-Hz rTMS can be tuned by tDCS preconditioning. Twelve healthy subjects participated in the study. Brief trains of 5-Hz rTMS were applied to the primary motor cortex at an intensity of 120% of the resting motor threshold, with recording of the electromyograph traces evoked by each stimulus o…
Associations of Genetic Susceptibility to Alzheimer’s Disease with Adiposity and Cardiometabolic Risk Factors among Children in a 2-Year Follow-up St…
2018
We investigated the associations of genetic risk score (GRS) for Alzheimer's disease and apolipoprotein E (APOE) ɛ variant with cardiometabolic risk factors during 2-year follow-up in children and whether body fat percentage (BF%) modify these associations. A population-based sample of 469 children (246 boys, 223 girls) at baseline and 398 children (201 boys, 197 girls) at 2-year follow-up participated in the study. Genotyping was performed using the Illumina Custom Infinium CardioMetabo BeadChip and the Illumina Infinium HumanCoreExome BeadChip. The GRS was calculated using information on nine independent gene variants available in our genomic data. We assessed BF%, waist circumference, in…
Single intense prenatal stress reduce behavioural suppression in an operant conflict paradigm in the adult progeny. Influence of Metyrapone administr…
2008
Stressors presented during late prenatal period can have long-term effects on offspring behaviour (1). Indeed we showed that in the rat progeny a single immobilization procedure at gestational day 16 enhances spatial learning in a non-aversive, rewarded-facilitated learning task, the Can Test, and decreases anxiety-like behaviour in the elevated plus maze (2). In this study, we wanted to investigate: (i) the effects of a single prenatal immobilization-stress on the operant conflict task (OCT), an anxiety-related procedure, in which positively reinforced responses are suppressed by contingent punishment (3); (ii) the expression of mineralcorticoid and glucocorticoid receptors (MRs, GRs) in t…
AAV vector-mediated overexpression of CB1 cannabinoid receptor in pyramidal neurons of the hippocampus protects against seizure-induced excitoxicity.
2010
The CB1 cannabinoid receptor is the most abundant G-protein coupled receptor in the brain and a key regulator of neuronal excitability. There is strong evidence that CB1 receptor on glutamatergic hippocampal neurons is beneficial to alleviate epileptiform seizures in mouse and man. Therefore, we hypothesized that experimentally increased CB1 gene dosage in principal neurons would have therapeutic effects in kainic acid (KA)-induced hippocampal pathogenesis. Here, we show that virus-mediated conditional overexpression of CB1 receptor in pyramidal and mossy cells of the hippocampus is neuroprotective and moderates convulsions in the acute KA seizure model in mice. We introduce a recombinant a…
Aspartoacylase-lacZ knockin mice: an engineered model of Canavan disease.
2011
Canavan Disease (CD) is a recessive leukodystrophy caused by loss of function mutations in the gene encoding aspartoacylase (ASPA), an oligodendrocyte-enriched enzyme that hydrolyses N-acetylaspartate (NAA) to acetate and aspartate. The neurological phenotypes of different rodent models of CD vary considerably. Here we report on a novel targeted aspa mouse mutant expressing the bacterial β-Galactosidase (lacZ) gene under the control of the aspa regulatory elements. X-Gal staining in known ASPA expression domains confirms the integrity of the modified locus in heterozygous aspa lacZ-knockin (aspa(lacZ/+)) mice. In addition, abundant ASPA expression was detected in Schwann cells. Homozygous (…
Abnormal facilitatory mechanisms in motor cortex of migraine with aura
2010
Experimental evidence suggests impairment of inhibitory intracortical circuits in migraine, while not much is known about activity of facilitatory intracortical circuits. In the present work we evaluated the effects of high frequency-repetitive transcranial magnetic stimulation (hf-rTMS) on the activity of facilitatory circuits of motor cortex in 18 patients affected by migraine with aura and 18 healthy subjects. Trains of 10 stimuli were applied to the motor cortex at 5-Hz frequency with recording of the EMG traces from the contralateral abductor pollicis brevis muscle (APB). Two intensities of stimulation (110% and 130% of resting motor threshold) were used in order to explore whether mot…
From different neurophysiological methods to conflicting pathophysiological views in migraine: a critical review of literature.
2014
Abnormal increased cortical responsivity to various types of stimuli plays a major role in migraine pathogenesis. Neurophysiological studies, however, have provided ambiguous findings of either hypo or hyper cortical excitability. This is why the term "dysexcitability" has been recently proposed to indicate a more general dysregulation of cortical excitability. The aims of this review are: (1) to provide existing knowledge and research advances in migraine pathophysiology; (2) to propose a unitary interpretation of apparently conflicting neurophysiological findings. Data of studies conducted in migraine through various evoked potentials techniques and non-invasive brain stimulation methods …
Cardiorespiratory Fitness, Physical Activity, and Insulin Resistance in Children
2020
Purpose Few studies have investigated the independent and joint associations of cardiorespiratory fitness (CRF) and body fat percentage (BF%) with insulin resistance in children. We investigated the independent and combined associations of CRF and BF% with fasting glycemia and insulin resistance and their interactions with physical activity (PA) and sedentary time among 452 children age 6 to 8 yr. Methods We assessed CRF with a maximal cycle ergometer exercise test and used allometrically scaled maximal power output (Wmax) for lean body mass (LM) and body mass (BM) as measures of CRF. The BF% and LM were measured by dual-energy X-ray absorptiometry, fasting glycemia by fasting plasma glucos…
Mechanisms involved in the control of feeding behavior in relation to food flavor
2016
Revue; IntroductionIntake is one of the most essential behaviors, since human beings, like any living organism, require adequate nutrients for their survival. Ingestive behavior is controlled to maintain energy balance by peripheral and central mechanisms. When physiological needs are not being met, they will lead to motivation. Thus, being hungry will motivate us to find food, and the motivation will cease when needs are met. Ingestive behavior is thus initially due to a need related to internal signals (Fig. 10.1), in this case, hunger (physiological need) and appetite (urge to eat a food from which we expect pleasure and satisfaction). Sensory (visual, olfactory and, to a lesser extent, …
Cyclical changes of cortical excitability and metaplasticity in migraine: evidence from a repetitive transcranial magnetic stimulation study.
2013
The primary brain dysfunctions leading to the onset of a migraine attack remain largely unknown. Other important open questions concern the mechanisms of initiation, continuation, and termination of migraine pain, and the changes in brain function underlying migraine transformation. Brief trains of high-frequency repetitive transcranial magnetic stimulation (rTMS), when applied to the primary motor cortex at suprathreshold intensity (⩾120% of resting motor threshold [RMT]), elicit in healthy subjects a progressive, glutamate-dependent facilitation of the motor evoked potentials (MEP). Conversely, in conditions of increased cortical excitability, the rTMS trains induce inhibitory MEP respons…