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The ability to predict the weight of objects is important for skilled and dexterous manipulation during activities of daily living. The observation of other people moving objects might represent an important source of information on... more
The ability to predict the weight of objects is important for skilled and dexterous manipulation during activities of daily living. The observation of other people moving objects might represent an important source of information on object features and help to plan the correct motor interaction with it. In aging, an impaired ability to evaluate the object weight might have negative drawbacks in term of the safety of the person. The aim of this study was to investigate the role of aging in the ability to discriminate the object weight during action observation. Twenty older adults (Old) and twenty young subjects (Young) performed a two-interval forced-choice task consisting in the observation of a couple of videos showing an actor moving a box of different weights. The observer had to evaluate which video showed the heavier box. Handgrip strength was acquired from all subjects. Sensitivity analysis was performed and psychometric curves were built on participants’ responses. The resul...
OBJECTIVE Transcranial magnetic stimulation (TMS) delivered over the cerebellum 5-7 ms prior to a stimulus over the contralateral primary motor cortex (M1) reduces the excitability of M1 output, a phenomenon termed cerebellar brain... more
OBJECTIVE Transcranial magnetic stimulation (TMS) delivered over the cerebellum 5-7 ms prior to a stimulus over the contralateral primary motor cortex (M1) reduces the excitability of M1 output, a phenomenon termed cerebellar brain inhibition (CBI). The cerebellum receives sensory information for adaptive motor coordination and motor planning. Here, we explored through TMS whether a peripheral electrical stimulus modulates CBI. METHODS We studied the effect of right median nerve electrical stimulation (ES) on CBI from right cerebellum (conditioning stimulus, CS) to left M1 (test stimulus, TS) in 12 healthy subjects. The following ES-CS inter-stimulus intervals (ISIs) were tested: 25, 30 and 35 ms. CS-TS ISI was set at 5 ms. RESULTS We found significantly weaker CBI when the ES was delivered 25 ms (p < 0.001) and 35 ms (p < 0.001) earlier the CS over the ipsilateral cerebellum and a trend for 30 ms ES-CS ISI (p = 0.07). CONCLUSIONS We hypothesize that the activation of cerebellar interneurons together with intrinsic properties of Purkinje cells may be responsible of the decreased CBI when the peripheral stimulation preceded the cerebellar stimulation of 25 and 35 ms. SIGNIFICANCE To test the interaction between somatosensory inputs and cerebello-cortical pathway may be important in a variety of motor tasks and neuropsychiatric disorders.
Key points The combination of action observation (AO) and a peripheral nerve stimulation has been shown to induce plasticity in the primary motor cortex (M1). However, using peripheral nerve stimulation little is known about the... more
Key points The combination of action observation (AO) and a peripheral nerve stimulation has been shown to induce plasticity in the primary motor cortex (M1). However, using peripheral nerve stimulation little is known about the specificity of the sensory inputs. The current study, using muscle tendon vibration to stimulate muscle spindles and transcranial magnetic stimulation to assess M1 excitability, investigated whether a proprioceptive stimulation leading to a kinaesthetic illusion of movement (KI) was able to evoke M1 plasticity when combined with AO. M1 excitability increased immediately and up to 60 min after AO‐KI stimulation as a function of the vividness of the perceived illusion, and only when the movement directions of AO and KI were congruent. Tactile stimulation coupled with AO and KI alone were not sufficient to induce M1 plasticity. This methodology might be proposed to subjects during a period of immobilization to promote M1 activity without requiring any voluntary movement. Physical practice is crucial to evoke cortical plasticity, but motor cognition techniques, such as action observation (AO), have shown their potentiality in promoting it when associated with peripheral afferent inputs, without the need of performing a movement. Here we investigated whether the combination of AO and a proprioceptive stimulation, able to evoke a kinaesthetic illusion of movement (KI), induced plasticity in the primary motor cortex (M1). In the main experiment, the role of congruency between the observed action and the illusory movement was explored together with the importance of the specificity of the sensory input modality (proprioceptive vs. tactile stimulation) to induce plasticity in M1. Further, a control experiment was carried out to assess the role of the mere kinaesthetic illusion on M1 excitability. Results showed that the combination of AO and KI evoked plasticity in M1, with an increase of the excitability immediately and up to 60 min after the conditioning protocol (P always <0.05). Notably, a significant increase in M1 excitability occurred only when the directions of the observed and illusory movements were congruent. Further, a significant positive linear relationship was found between the amount of M1 excitability increase and the vividness of the perceived illusion (P = 0.03). Finally, the tactile stimulation coupled with AO was not sufficient to induce changes in M1 excitability as well as the KI alone. All these findings indicate the importance of combining different sensory input signals to induce plasticity in M1, and that proprioception is the most suitable sensory modality to allow it.
Social distancing norms have been promoted after the COVID-19 pandemic. In this work, we tested interpersonal space (IPS) in 107 subjects through a reaching-comfort distance estimation task. In the main experiment, subjects had to... more
Social distancing norms have been promoted after the COVID-19 pandemic. In this work, we tested interpersonal space (IPS) in 107 subjects through a reaching-comfort distance estimation task. In the main experiment, subjects had to estimate the comfort and reach space between an avatar wearing or not wearing a face mask. We found that IPS was greater between avatars not wearing a mask with respect to stimuli with the mask on, while reaching space was not modulated. IPS increment in the NoMask condition with respect to the Mask condition correlated with anxiety traits, as shown with the State-Trait Anxiety Inventory, rather than with transient aspects related to the pandemic situation. In the control experiment, the avatars with a mask were removed to further explore the conditioning effect provided by the presence of the facial protection in the main experiment. We found a significant difference comparing this condition with the same condition of the main experiment, namely, the dist...
OBJECTIVE Transcranial magnetic stimulation (TMS) delivered over the cerebellum 5-7 ms prior to a stimulus over the contralateral primary motor cortex (M1) reduces the excitability of M1 output, a phenomenon termed cerebellar brain... more
OBJECTIVE Transcranial magnetic stimulation (TMS) delivered over the cerebellum 5-7 ms prior to a stimulus over the contralateral primary motor cortex (M1) reduces the excitability of M1 output, a phenomenon termed cerebellar brain inhibition (CBI). The cerebellum receives sensory information for adaptive motor coordination and motor planning. Here, we explored through TMS whether a peripheral electrical stimulus modulates CBI. METHODS We studied the effect of right median nerve electrical stimulation (ES) on CBI from right cerebellum (conditioning stimulus, CS) to left M1 (test stimulus, TS) in 12 healthy subjects. The following ES-CS inter-stimulus intervals (ISIs) were tested: 25, 30 and 35 ms. CS-TS ISI was set at 5 ms. RESULTS We found significantly weaker CBI when the ES was delivered 25 ms (p < 0.001) and 35 ms (p < 0.001) earlier the CS over the ipsilateral cerebellum and a trend for 30 ms ES-CS ISI (p = 0.07). CONCLUSIONS We hypothesize that the activation of cerebellar interneurons together with intrinsic properties of Purkinje cells may be responsible of the decreased CBI when the peripheral stimulation preceded the cerebellar stimulation of 25 and 35 ms. SIGNIFICANCE To test the interaction between somatosensory inputs and cerebello-cortical pathway may be important in a variety of motor tasks and neuropsychiatric disorders.
This study aimed to investigate the role of sensorimotor expertise in evaluating relative weight of a lifted object during the observation of a sport-specific gesture, namely the deadlift. Fifty-six participants, assigned to three groups... more
This study aimed to investigate the role of sensorimotor expertise in evaluating relative weight of a lifted object during the observation of a sport-specific gesture, namely the deadlift. Fifty-six participants, assigned to three groups according to their experience in weight lifting, powerlifters, CrossFit® practitioners and naïve participants (controls), performed a perceptual weight judgments task. Participants observed videos showing a powerlifter executing a deadlift at the 80%, 90% and 100% of 1 repetition maximum (1RM) and answered a question about the weight of the lifted object. Participants' response accuracy and variability were evaluated. Findings showed that powerlifters were more accurate than controls. No differences appeared between powerlifter and CrossFit® practitioners, and between CrossFit® practitioners and controls. Response variability was similar in the three groups. These findings suggest that a fine sensorimotor expertise specific for the observed gest...
Co-development of action, conceptualization and social interaction mutually scaffold and support each other within a virtuous feedback cycle in the development of human language in children. Within this framework, the purpose of this... more
Co-development of action, conceptualization and social interaction mutually scaffold and support each other within a virtuous feedback cycle in the development of human language in children. Within this framework, the purpose of this article is to bring together diverse but complementary accounts of research methods that jointly contribute to our understanding of cognitive development and in particular, language acquisition in robots. Thus, we include research pertaining to developmental robotics, cognitive science, psychology, linguistics and neuroscience, as well as practical computer science and engineering. The different studies are not at this stage all connected into a cohesive whole; rather, they are presented to illuminate the need for multiple different approaches that complement each other in the pursuit of understanding cognitive development in robots. Extensive experiments involving the humanoid robot iCub are reported, while human learning relevant to developmental robo...
This study investigated the effects induced by 8 weeks of two high-intensity interval training (HIIT) protocols, 10–20–30 and 30–30 concepts, characterized by significantly different training volume and intensity, on physiological... more
This study investigated the effects induced by 8 weeks of two high-intensity interval training (HIIT) protocols, 10–20–30 and 30–30 concepts, characterized by significantly different training volume and intensity, on physiological parameters, running performance, body composition and psychophysiological stress of recreational divided into two groups: the 10–20–30 group performed two 10–20–30 sessions/wk and one continuous training (CT)/wk, whilst the 30–30 group performed two 30–30 sessions/wk and one CT session/wk. VO2max, 1 km time, maximal aerobic speed (MAS), and body composition were evaluated before and after intervention. Internal load was measured through rating of perceived exertion (RPE). Both groups significantly improved running performance (1 km time: p=0.04; MAS: p=0.000001), aerobic fitness (VO2max: p=0.000002) and body composition (lean mass (kg) p=0.0001; fat mass (%) p=0.00005). RPE resulted significantly lower in the 10–20–30 group than in 30–30 group (10–20–30: 1...
Tendon vibration of a limb elicits illusory movements in the direction that the vibrated muscle would be stretched, followed by a transient perception of movement in the opposite direction, that was demonstrated to correspond to a... more
Tendon vibration of a limb elicits illusory movements in the direction that the vibrated muscle would be stretched, followed by a transient perception of movement in the opposite direction, that was demonstrated to correspond to a “cortical” aftereffect (Goodwin et al. Science 175:1382–1384, 1972). Primary motor cortex (M1) excitability of the non-vibrated antagonist muscle of the vibrated muscle increased during vibration and decreased thereafter. The cortical aftereffect is of interest when considering the possibility to use tendon vibration in rehabilitation for restoring unbalance activity between antagonistic muscles but, due to its short-lasting duration, has not been explored so far. We investigated the possibility to consolidate the cortical aftereffect by combining tendon vibration with a concomitant high-frequency 5-Hz repetitive transcranial magnetic stimulation (rTMS) protocol. The distal tendon of the flexor carpi radialis muscle (FCR) was vibrated and concomitantly a 2...
Background: Transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (dlPFC) might be a promising treatment strategy for depression. As disturbances in psychomotor activity are one of the key... more
Background: Transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (dlPFC) might be a promising treatment strategy for depression. As disturbances in psychomotor activity are one of the key features of unipolar depression are, we aimed to evaluate the behavioral effects of ten tDCS sessions over a 5-day period on psychomotor retardation in depressed patients. Methods: Twenty-three treatment-resistant depressed patients received either active or sham anodal tDCS to the left dorsolateral prefrontal cortex (2 mA, 10 sessions over 1 week). Psychomotor functioning was registered by means of observer ratings (Salpêtrière Retardation Rating Scale—SRRS) and objective measures (kinematical analysis of movements, automatic imitation). Results: tDCS sessions resulted in improvements on SRRS scores, although active tDCS was not significantly superior to sham tDCS on the kinematical parameters. Furthermore, no general additional antidepressant effect of...
Department of Experimental Medicine, Section of Human Physiology, Centro Polifunzionale di Scienze Motorie, University of Genoa, Genoa, Italy Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology... more
Department of Experimental Medicine, Section of Human Physiology, Centro Polifunzionale di Scienze Motorie, University of Genoa, Genoa, Italy Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva and Campus SUVA, Sion, Switzerland Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland INSERM, U1093, Cognition Action Plasticité Sensorimotrice, Université de Bourgogne, Dijon, France Fondazione Istituto Italiano di Tecnologia, Centro di Neurofisiologia Traslazionale c/o Sezione Fisiologia Umana, Ferrara, Italy Neural Control of Movement Laboratory, ETH Zurich, Zurich, Switzerland
Motor resonance mechanisms are known to affect humans' ability to interact with others, yielding the kind of “mutual understanding” that is the basis of social interaction. However, it remains unclear how the partner's action... more
Motor resonance mechanisms are known to affect humans' ability to interact with others, yielding the kind of “mutual understanding” that is the basis of social interaction. However, it remains unclear how the partner's action features combine or compete to promote or prevent motor resonance during interaction. To clarify this point, the present study tested whether and how the nature of the visual stimulus and the properties of the observed actions influence observer's motor response, being motor contagion one of the behavioral manifestations of motor resonance. Participants observed a humanoid robot and a human agent move their hands into a pre-specified final position or put an object into a container at various velocities. Their movements, both in the object- and non-object- directed conditions, were characterized by either a smooth/curvilinear or a jerky/segmented trajectory. These trajectories were covered with biological or non-biological kinematics (the latter onl...
Cryostimulation is currently seen as a potential adjuvant strategy to tackle obesity and dysmetabolism by triggering cold-induced thermogenesis. Although suggestive, the underlying mechanisms are still poorly elucidated. We tested whether... more
Cryostimulation is currently seen as a potential adjuvant strategy to tackle obesity and dysmetabolism by triggering cold-induced thermogenesis. Although suggestive, the underlying mechanisms are still poorly elucidated. We tested whether single or repeated applications of partial-body cryostimulation (PBC) could influence resting energy expenditure (REE) in exposed individuals. Fifteen middle-aged obese and sixteen control lean women (body mass index 31 ± 1.6 kg/m2 and 22 ± 1.7 kg/m2) underwent a daily PBC (−130 °C × 150 s) for five consecutive days. Resting energy metabolism (REE) was assessed by indirect calorimetry pre- and post-PBC on day 1 and day 5. As concerns REE, the linear mixed model revealed that REE changes were explained by session and time (F1,29 = 5.58; p = 0.02; ƞp2 = 0.16) independent of the group (F1,29 = 2.9; p = 0.09; ƞp2 = 0.09). REE pre-PBC increased from day 1 to day 5 either in leans (by 8.2%, from 1538 ± 111 to 1665 ± 106 kcal/day) or in obese women (by 5....
This study compared the effects of two breathing conditions during the freestyle turn approach phase in swimmers. Thirty-four prepubertal swimmers (mean ± SD: 10.59 ± 0.97 years) were divided into two groups: No Breath (NB), not breathing... more
This study compared the effects of two breathing conditions during the freestyle turn approach phase in swimmers. Thirty-four prepubertal swimmers (mean ± SD: 10.59 ± 0.97 years) were divided into two groups: No Breath (NB), not breathing at the last stroke, and Breath Stroke (BS). Swimmers performed three turns with 5 min of rest between the repetitions. Kinematic parameters were recorded with two underwater and two surface cameras. Total turn time (NB: 9.31 ± 1.34 s; BS: 10.31 ± 1.80 s; p = 0.049), swim-in time (NB: 3.89 ± 0.63 s; BS 4.50 ± 0.79 s; p = 0.02) and rotation time (NB: 2.42 ± 0.29 s; BS: 3.03 ± 0.41 s; p = 0.0001) were significantly shorter and swim-in distance [NB: 0.70 (0.58,0.77) m; BS: 0.47 (0.34,0.55) m; p = 0.0001], glide distance (NB: 1.06 ± 0.21 m; BS: 0.70 ± 0.20 m; p = 0.0001) and surfacing distance [NB: 1.79 (1.19,2.24) m; BS: 1.18 (0.82,1.79) m; p = 0.043] were significantly longer in NB than in BS. Moreover, speed-in (NB: 1.04 ± 0.14 m/s; BS: 0.93 ± 0.14 m...
The hand-blink reflex (HBR) is a subcortical response, elicited by the electrical stimulation of the median nerve, whose magnitude is specifically modulated according to the spatial properties of the defensive peripersonal space (DPPS) of... more
The hand-blink reflex (HBR) is a subcortical response, elicited by the electrical stimulation of the median nerve, whose magnitude is specifically modulated according to the spatial properties of the defensive peripersonal space (DPPS) of the face. For these reasons, the HBR is commonly used as a model to assess the DPPS of the face. Little is known on the effects induced by the activation of cutaneous afferents from the face on the DPPS of the face. Therefore, we tested the effect of non-painful transcutaneous trigeminal nerve stimulation (TNS) on the amplitude of the HBR. Fifteen healthy participants underwent HBR recording before and after 20 min of sham- and real-TNS delivered bilaterally to the infraorbital nerve in two separate sessions. The HBR was recorded bilaterally from the orbicularis oculi muscles, following non-painful median nerve stimulation at the wrist. The HBR amplitude was assessed in the “hand‐far” and “hand‐near” conditions, relative to the hand position in res...
Humans can acquire information on others’ motor outputs (action prediction) and intentions (action understanding) according to their individual motor repertoire and to the detected gesture’s features (e.g. temporal patterns). We aimed at... more
Humans can acquire information on others’ motor outputs (action prediction) and intentions (action understanding) according to their individual motor repertoire and to the detected gesture’s features (e.g. temporal patterns). We aimed at dissociating between action prediction and action understanding abilities in soccer players and novices observing soccer action videos including correct-timing (CTP) or delayed (DP) passes. First, we used an occluding paradigm to evaluate participants’ ability to predict the correct time to pass the ball. Although soccer players showed reduced reaction times, all subjects showed a similar pattern of performance: during DP observation, responses appeared delayed with respect to the other conditions but anticipated with respect to the observed DP. In a separate experiment, we investigated the ability to recognize CTP vs. DP and the modulation of primary motor cortex (M1) excitability associated to video observation. Only soccer players showed selectiv...
The present study aimed to evaluate the effects of two types of 9-month adapted physical activity (APA) program, based on a muscle reinforcement training and a postural training, respectively, on muscle mass, muscle strength, and static... more
The present study aimed to evaluate the effects of two types of 9-month adapted physical activity (APA) program, based on a muscle reinforcement training and a postural training, respectively, on muscle mass, muscle strength, and static balance in moderate sarcopenic older women. The diagnosis of sarcopenia was done in accordance with measurable variables and cut-off points suggested by the European Working Group on Sarcopenia in Older People (EWGSOP). Seventy-two participants were randomly assigned to two groups: the muscle reinforcement training group (RESISTANCE) (n=35; 69.9 ± 2.7 years) and the postural training group (POSTURAL) (n=37; 70.0±2.8 years). Body composition, muscle mass, skeletal muscle mass index (SMI), and handgrip strength (HGS) were evaluated for sarcopenia assessment, whereas Sway Path, Sway Area, Stay Time, and Spatial Distance were evaluated for static balance assessment. Sixty-six participants completed the study (RESISTANCE group: n=33; POSTURAL group: n=33)...
The combination of action observation (AO) and a peripheral nerve stimulation has been shown to induce plasticity in the primary motor cortex (M1). However, using peripheral nerve stimulation little is known about the specificity of the... more
The combination of action observation (AO) and a peripheral nerve stimulation has been shown to induce plasticity in the primary motor cortex (M1). However, using peripheral nerve stimulation little is known about the specificity of the sensory inputs. The current study, using muscle tendon vibration to stimulate muscle spindles and transcranial magnetic stimulation to assess M1 excitability, investigated whether a proprioceptive stimulation leading to a kinaesthetic illusion of movement (KI) was able to evoke M1 plasticity when combined with AO. M1 excitability increased immediately and up to 60 min after AO‐KI stimulation as a function of the vividness of the perceived illusion, and only when the movement directions of AO and KI were congruent. Tactile stimulation coupled with AO and KI alone were not sufficient to induce M1 plasticity. This methodology might be proposed to subjects during a period of immobilization to promote M1 activity without requiring any voluntary movement.
Before movement onset, during the reaction time, excitability of M1 is selectively modulated by somatosensory inputs, only in the movement-related muscle. If a similar mechanism operates before the onset of mental movements, then... more
Before movement onset, during the reaction time, excitability of M1 is selectively modulated by somatosensory inputs, only in the movement-related muscle. If a similar mechanism operates before the onset of mental movements, then somatosensory afferent inputs are exploited during cognitive representation of movement. We assessed sensorimotor modulation through short latency afferent inhibition (SAI) paradigm before the onset of executed and imagined movements. Participants performed or imagined an abduction of index or little finger, in response to an acoustic signal. SAI was evaluated between a Warning and a Go signal and 100 ms after the Go signal, before the real or expected EMG activity. Results showed a reduction of SAI after the Go signal, in the movement-related muscle, during motor imagery as well as movement execution. There was a positive correlation between the individual degree of sensorimotor modulation during executed and mental movements and between the sensorimotor modulation during mental movements and motor imagery ability. Sensorimotor modulation operates during the cognitive representation of movement with selective disinhibition of the cortical representation of the muscle involved in the task. Sensorimotor modulation mechanisms prior to mental and executed movements likely share overlapping circuits.
Action observation is known to enhance sensorimotor system activation, and such effect has been linked to neural priming and response facilitation mechanisms. This facilitation effect, however, has been primarily studied by focusing on... more
Action observation is known to enhance sensorimotor system activation, and such effect has been linked to neural priming and response facilitation mechanisms. This facilitation effect, however, has been primarily studied by focusing on high-level motor proficiency, whereas evidence on the effect of observing poorly performed actions is still lacking. We then devised a study to investigate neural correlates of the observation of suboptimal motor acts as mirrored by corticospinal activation (via transcranial magnetic stimulation (TMS), Experiment 1) and by modulation of cortical oscillatory activity (via electroencephalography (EEG), Experiment 2). 40 participants were presented with four randomly reiterated videos. Videos depicted a healthy confederate, a minimally impaired multiple sclerosis (MS) patient, a mildly impaired MS patient, or a confederate trying to simulate mild motor difficulties performing a test concerning fine motor abilities. In Experiment 1 we analyzed TMS-induced...

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