Search results for "Motor system"

Muscle effort is best minimized by the right-dominant arm in the gravity field

2021

AbstractThe central nervous system (CNS) is thought to develop motor strategies that minimize various hidden criteria, such as end-point variance or effort. A large body of literature suggests that the dominant arm is specialized for such open-loop optimization-like processes whilst the non-dominant arm is specialized for closed-loop control. Building on recent results suggesting that the brain plans arm movements that takes advantage of gravity effects to minimize muscle effort, the present study tests the hypothesized superiority of the dominant arm motor system for effort minimization. Thirty participants (22.5 ± 2.1 years old; all right-handed) performed vertical arm movements between t…

Integration of Gravitational Torques in Cerebellar Pathways Allows for the Dynamic Inverse Computation of Vertical Pointing Movements of a Robot Arm

2008

BackgroundSeveral authors suggested that gravitational forces are centrally represented in the brain for planning, control and sensorimotor predictions of movements. Furthermore, some studies proposed that the cerebellum computes the inverse dynamics (internal inverse model) whereas others suggested that it computes sensorimotor predictions (internal forward model).Methodology/principal findingsThis study proposes a model of cerebellar pathways deduced from both biological and physical constraints. The model learns the dynamic inverse computation of the effect of gravitational torques from its sensorimotor predictions without calculating an explicit inverse computation. By using supervised …

P 56 tDCS shows no effects on motor cortex excitability at rest

2017

Introduction Transcranial direct current stimulation (tDCS) is a widely used technique in research and clinics. However, the underlying physiological mechanisms are not yet clear. Modeling studies suggest that the electric field during tDCS is dominated by a tangential component which predominantly modifies active synaptic connections ( Radman et al., 2007 ). We have previously shown that tDCS with an increased tangential compared to the conventional montage introduced by Nitsche and Paulus (2000) , suppresses the effects of paired associative stimulation of the supplementary motor area and the primary motor cortex (PASSMA-M1) independent of tDCS polarity (Faber et al., under submission). H…

Fos mapping of brain activation induced by the mammary pheromone in the newborn rabbit

2010

The female European rabbit, Oryctolagus cuniculus, displays a surprising maternal behaviour. Indeed, she comes into the nest only once per day and for a very brief period (3-4 minutes), almost exclusively to nurse. A pheromonal signal identified as the 2-methylbut-2-enal and named the mammary pheromone (MP) is emitted in milk by all lactating rabbit females. This chemosensory cue induces typical head-searching and oral-seizing movements in newborn rabbits usually involved in the localisation of the nipples. The MP therefore appears as a biological signal important for sucking, survival and growth in pups. To date, only few data are available regarding the neuronal substrate which sustains t…

Might as well jump: Sound affects muscle activation in skateboarding

2014

The aim of the study is to reveal the role of sound in action anticipation and performance, and to test whether the level of precision in action planning and execution is related to the level of sensorimotor skills and experience that listeners possess about a specific action. Individuals ranging from 18 to 75 years of age - some of them without any skills in skateboarding and others experts in this sport - were compared in their ability to anticipate and simulate a skateboarding jump by listening to the sound it produces. Only skaters were able to modulate the forces underfoot and to apply muscle synergies that closely resembled the ones that a skater would use if actually jumping on a ska…

Bascule syndrome associated with syncopal episodes.

2018

Bascule syndrome is a recently described benign vasomotor dermatosis characterized by Bier anemic spots, cyanosis, and urticaria-like eruption. We report a case of a 13-year-old girl with cutaneous lesions consistent with Bascule syndrome who had had three exercise-related syncopal episodes. It would be recommended to exclude orthostatic intolerance or postural orthostatic tachycardia syndrome when evaluating patients with Bascule syndrome.

2019

Current research demonstrates beneficial effects of physical activity on brain functions and cognitive performance. To date, less is known on the effects of gross motor movements that do not fall into the category of sports-related aerobic or anaerobic exercise. In previous studies, we found beneficial effects of dynamic working environments, i.e., environments that encourage movements during cognitive task performance, on cognitive performance and corresponding brain activity. Aim of the present study was to examine the effects of working in a dynamic and a static office environment on attentional and vigilance performance, and on the corresponding electroencephalographic (EEG) brain oscil…

Interhemispheric inhibition during mental actions of different complexity.

2013

International audience; Several investigations suggest that actual and mental actions trigger similar neural substrates. Yet, neurophysiological evidences on the nature of interhemispheric interactions during mental movements are still meagre. Here, we asked whether the content of mental images, investigated by task complexity, is finely represented in the inhibitory interactions between the two primary motor cortices (M1s). Subjects' left M1 was stimulated by means of transcranial magnetic stimulation (TMS) while they were performing actual or mental movements of increasing complexity with their right hand and exerting a maximum isometric force with their left thumb and index. Thus, we sim…

Fluent Speakers of a Second Language Process Graspable Nouns Expressed in L2 Like in Their Native Language

2017

According to embodied cognition, language processing relies on the same neural structures involved when individuals experience the content of language material. If so, processing nouns expressing a motor content presented in a second language should modulate the motor system as if presented in the mother tongue. We tested this hypothesis using a go-no go paradigm. Stimuli included English nouns and pictures depicting either graspable or non-graspable objects. Pseudo-words and scrambled images served as controls. Italian participants, fluent speakers of English as a second language, had to respond when the stimulus was sensitive and refrain from responding when it was not. As foreseen by emb…

The role of motor system in action-related language comprehension in L1 and L2: An fMRI study

2018

The framework of embodied cognition has challenged the modular view of a language-cognition divide by suggesting that meaning-retrieval critically involves the sensory-motor system. Despite extensive research into the neural mechanisms underlying language-motor coupling, it remains unclear how the motor system might be differentially engaged by different levels of linguistic abstraction and language proficiency. To address this issue, we used fMRI to quantify neural activations in brain regions underlying motor and language processing in Chinese-English speakers’ processing of literal, metaphorical, and abstract language in their L1 and L2. Results overall revealed a response in motor ROIs …