Objective: Parkinson's disease (PD) patients exhibit changes in mechanisms underlying movement preparation, particularly the suppression of corticospinal excitability - termed "preparatory suppression" - which is thought to facilitate movement execution in healthy individuals. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) being an attractive treatment for advanced PD, we aimed to study the potential contribution of this nucleus to PD-related changes in such corticospinal dynamics.
Methods: On two consecutive days, we applied single-pulse transcranial magnetic stimulation to the primary motor cortex of 20 advanced PD patients treated with bilateral STN-DBS (ON vs.
Background: Chemotherapy with lomustine is widely considered as standard treatment option for progressive glioblastoma. The value of adding radiotherapy to second-line chemotherapy is not known.
Methods: EORTC-2227-BTG (LEGATO, NCT05904119) is an investigator-initiated, pragmatic (PRECIS-2 score: 34 out of 45), randomized, multicenter phase III trial in patients with first progression of glioblastoma.
Background And Objectives: Perioperative psychological stress and pharmacological anxiolysis can negatively affect the quality of recovery after total knee arthroplasty. We aimed to assess whether hypnosis combined with virtual reality could reduce intraoperative pharmacological sedation and improve quality of recovery after total knee arthroplasty surgery.
Methods: In this prospective randomized clinical trial, 60 patients scheduled for total knee arthroplasty with spinal anesthesia were randomly divided into 2 groups of 30 patients each.
Background: Obsessive compulsive disorder (OCD) and Gilles de la Tourette syndrome (GTS) are neurodevelopmental disorders characterized by difficulties in controlling intrusive thoughts (obsessions) and undesired actions (tics), respectively. Both conditions have been associated with abnormal inhibition but a tangible deficit of inhibitory control abilities is controversial in GTS.
Methods: Here, we examined a 25 years-old male patient with severe OCD symptoms and a mild form of GTS, where impairments in motor control were central.
Background: Anxiety and depression are psychopathological states frequently co-occurring with severe alcohol use disorder (SAUD). These symptoms generally disappear with abstinence but may persist in some patients, increasing the relapse risk.
Methods: The cerebral cortex thickness of 94 male patients with SAUD was correlated with symptoms of depression and anxiety, both measured at the end (2-3 weeks) of the detoxification treatment.
While the impact of the gut microbiota on brain and behavior is increasingly recognized, human studies examining this question are still scarce. The primary objective of the current study was to explore the potential relationships between the gut microbiota composition, motor cortical excitability at rest and during inhibitory control, as well as behavioral inhibition, in healthy volunteers and in patients suffering from alcohol use disorder. Motor cortical excitability was examined using a range of transcranial magnetic stimulation (TMS) measures probed at rest, including the recruitment curve, short and long intracortical inhibition, and intracortical facilitation within the primary motor cortex.
View Article and Find Full Text PDFBackground: In Parkinson's disease (PD), neurophysiological abnormalities within the primary motor cortex (M1) have been shown to contribute to bradykinesia, but exact modalities are still uncertain. We propose that such motor slowness could involve alterations in mechanisms underlying movement preparation, especially the suppression of corticospinal excitability-called "preparatory suppression"-which is considered to propel movement execution by increasing motor neural gain in healthy individuals.
Methods: On two consecutive days, 29 PD patients (on and off medication) and 29 matched healthy controls (HCs) underwent transcranial magnetic stimulation over M1, eliciting motor-evoked potentials (MEPs) in targeted hand muscles, while they were either at rest or preparing a left- or right-hand response in an instructed-delay choice reaction time task.
Neuroimage Clin
September 2021
Action preparation relies on the operation of control processes that modulate the excitability of the corticospinal tract. On the one hand, excitatory processes prepare the motor system for the forthcoming response; the stronger these influences, the stronger the tendency to act. On the other hand, inhibitory influences allow to suppress inappropriate actions and, more generally, to ensure some sort of impulse control.
View Article and Find Full Text PDFPatients with alcohol use disorder (AUD) present with important emotional, cognitive, and social impairments. The gut microbiota has been recently shown to regulate brain functions and behavior but convincing evidence of its role in AUD is lacking. Here, we show that gut dysbiosis is associated with metabolic alterations that affect behavioral (depression, sociability) and neurobiological (myelination, neurotransmission, inflammation) processes involved in alcohol addiction.
View Article and Find Full Text PDFInhibitory control underlies the ability to inhibit inappropriate responses and involves processes that suppress motor excitability. Such motor modulatory effect has been largely described during action preparation but very little is known about the neural circuit responsible for its implementation. Here, we addressed this point by studying the degree to which the extent of preparatory suppression relates to brain morphometry.
View Article and Find Full Text PDFA lack of inhibitory control appears to contribute to the development and maintenance of addictive disorders. Among the mechanisms thought to assist inhibitory control, an increasing focus has been drawn on the so-called preparatory suppression, which refers to the drastic suppression observed in the motor system during action preparation. Interestingly, deficient preparatory suppression has been reported in alcohol use disorders.
View Article and Find Full Text PDFBy applying transcranial magnetic stimulation (TMS) over primary motor cortex (M1) to elicit motor-evoked potentials (MEPs) in muscles of the contralateral hand during reaction time (RT) tasks, many studies have reported a strong global suppression of motor excitability during action preparation, a phenomenon called preparatory inhibition. Several hypotheses have been put forward regarding the role of this broad suppression, with the predominant view that it reflects inhibitory processes assisting action selection. However, this assumption is still a matter of debate.
View Article and Find Full Text PDFObjectives: Motor-evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) show a profound suppression when elicited during the instructed-delay of reaction time (RT) tasks. One predominant hypothesis is that this phenomenon, called "preparatory inhibition", reflects the operation of processes that suppress motor activity to withhold prepared (but delayed) responses, a form of impulse control. In addition, a startling acoustic stimulus (SAS) - a loud and narrow sound - can trigger the release of prepared responses in RT tasks.
View Article and Find Full Text PDFImpaired inhibitory control contributes to the development, maintenance, and relapse of alcohol-dependence, but the neural correlates of this deficit are still unclear. Because inhibitory control has been labeled as an executive function, most studies have focused on prefrontal areas, overlooking the contribution of more "primary" structures, such as the motor system. Yet, appropriate neural inhibition of the motor output pathway has emerged as a central aspect of healthy behavior.
View Article and Find Full Text PDFUsing instructed-delay choice reaction time (RT) paradigms, many previous studies have shown that the motor system is transiently inhibited during response preparation: motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex are typically suppressed during the delay period. This effect has been observed in both selected and non-selected effectors, although MEP changes in selected effectors have been more inconsistent across task versions. Here, we compared changes in MEP amplitudes in three different variants of an instructed-delay choice RT task.
View Article and Find Full Text PDFBackground: Binge co-consumption of highly caffeinated energy drinks with alcohol (ethanol [EtOH]) has become a common practice among adolescents/young adults and has been associated with an increased incidence of hazardous behaviors. Animal models are critical in advancing our understanding the neurobehavioral consequences of this form of binge drinking. Surprisingly, virtually no work has explored caffeine and EtOH co-consumption or its long-term consequences in adolescent animals.
View Article and Find Full Text PDFBackground: Many previous transcranial magnetic stimulation (TMS) studies have investigated corticospinal excitability changes occurring when choosing which hand to use for an action, one of the most frequent decision people make in daily life. So far, these studies have applied single-pulse TMS eliciting motor-evoked potential (MEP) in one hand when this hand is either selected or non-selected. Using such method, hand choices were shown to entail the operation of two inhibitory mechanisms, suppressing MEPs in the targeted hand either when it is non-selected (competition resolution, CR) or selected (impulse control, IC).
View Article and Find Full Text PDFAlcohol Clin Exp Res
February 2016
Background: Binge alcohol (ethanol [EtOH]) drinking is common during adolescence, a time characterized by many behavioral and neurobiological changes. Among them, the GABAA receptor system undergoes substantial modifications, including changes in the density, distribution, and subunit composition of the receptor. Based on its demonstrated role in EtOH consumption, this study aimed to investigate the effects of 2 different GABAA receptor agonists on binge-like EtOH intake in adolescent and adult mice using the Drinking-in-the-Dark model.
View Article and Find Full Text PDFRepeated drug injections lead to sensitization of their stimulant effects in mice, a phenomenon sometimes referred to as drug psychomotor sensitization. Previous studies showed that sensitization to cocaine is context dependent as its expression is reduced in an environment that was not paired with cocaine administration. In contrast, the effects of the test context on ethanol sensitization remain unclear.
View Article and Find Full Text PDFRepeated ethanol injections lead to a sensitization of its stimulant effects in mice. Some recent results argue against a role for ventral tegmental area (VTA) dopamine neurons in ethanol behavioral sensitization. The aim of the present study was to test whether in vivo ethanol locomotor sensitization correlates with changes in either basal- or ethanol-evoked firing rates of dopamine neurons in vitro.
View Article and Find Full Text PDFPsychopharmacology (Berl)
April 2014
Rationale: Due to their maturing brain, adolescents are suggested to be more vulnerable to the long-term consequences of chronic alcohol use. Increased sensitization to the stimulant effects of ethanol is a possible consequence of ethanol exposure during adolescence.
Objectives: The aim of this study was to characterize the long-term alterations in the stimulant effects of ethanol and in the rate of ethanol sensitization in mice pre-exposed to ethanol during adolescence in comparison to mice pre-exposed to ethanol in adulthood.
The adolescent brain has been suggested to be particularly sensitive to ethanol-induced neuroadaptations, which in turn could increase the risk of youths for alcohol abuse and dependence. Sensitization to the locomotor stimulant effects of ethanol has often been used as an animal model of ethanol-induced neuroadaptations. Previously, we showed that young mice were more sensitive than adults to the locomotor sensitization induced by high ethanol doses.
View Article and Find Full Text PDFRecent studies suggest that the brain histaminergic system and especially the H3 receptors are involved in the regulation of alcohol consumption and alcohol-induced behaviors. Part of this effect might be due to a modulation of ethanol-induced sedation by central histamine. The aim of the present study was to investigate the effects of several histaminergic drugs on ethanol-induced sedation using the loss of righting reflex experimental protocol in female Swiss mice.
View Article and Find Full Text PDFAlcohol exposure during early adolescence is believed to durably alter the behavioral properties of ethanol, increasing the likelihood of later alcohol-related disorders. The aim of the present experiments was to characterize changes in the behavioral effects of ethanol in adult female Swiss mice after a chronic ethanol exposure during adolescence, extending from postnatal day 28 to postnatal day 42. After a chronic ethanol exposure during adolescence (daily injections of 0, 2.
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