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1.
Annu Int Conf IEEE Eng Med Biol Soc ; 2022: 5103-5106, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36085879

RESUMO

Neurological disorders such as stroke remain leading causes of disability worldwide. A current thrust in the neurorehabilitation of such disorders involves exogenous neuromodulation of cranial nerves in order to enhance neuro-plasticity and maximize recovery of function. Here we present preliminary results on the effects of kilohertz range electrical stimulation of the trigeminal nerve (TNS) on motor learning, using an upper extremity visuomotor adaptation paradigm. Twenty-five (25) healthy adult subjects were randomly assigned to 2 groups: 3kHz stimulation ( n=13) and sham ( n=12). Participants performed a visuomotor rotation task that involved center-out reaching movements to eight vertically arranged targets. Four blocks of trials were performed: two baseline blocks with veridical visual feedback, one adaptation block involving a 30° CCW rotation of hand visual feedback, and one washout block with no rotation. TNS was applied for 20 minutes before the 2nd baseline block using two electrodes targeting the ophthalmic branches of the trigeminal nerve. Early in the rotation block, learning rates were similar between the 3kHz and sham groups but gradually diverged, with the 3kHz group demonstrating slightly faster rates than sham later in the rotation block. The results provide new information on the potential use of TNS in neurorehabilitation.


Assuntos
Desempenho Psicomotor , Percepção Visual , Adulto , Estimulação Elétrica , Humanos , Aprendizagem/fisiologia , Desempenho Psicomotor/fisiologia , Nervo Trigêmeo , Percepção Visual/fisiologia
2.
Brain Nerve ; 74(9): 1087-1093, 2022 Sep.
Artigo em Japonês | MEDLINE | ID: mdl-36065669

RESUMO

Although it has long been known that cortical contribution is undoubtedly necessary for visually guided modification of steps during locomotion, most of the physiological evidence for cortical contribution has been accumulated since the 1980s. This article reviews evidence obtained from experiments on cats that have demonstrated the involvement of the primary motor cortex (MI), posterior parietal cortex (PPC), and premotor areas (PM) in visually guided locomotion. Activity in the MI, which is tightly coupled with muscle activity of the contralateral limbs, has been thought to control muscle synergy of contralateral limbs through spinal interneurons to modify steps. Signals from the PPC are often effector-independent; this area signals spatiotemporal relationships between an obstacle and the body. Activity in the PM is more effector-specific than that in the PPC; the PM seems to receive the spatiotemporal information from the PPC and transform it to effector-specific signals that allow the MI to send commands to modify steps taken by the contralateral limbs. These findings support the view that network activity between the PPC and PM is necessary for controlling not only segmental movements such as reaching with one arm, but also visually guided locomotion.


Assuntos
Córtex Motor , Desempenho Psicomotor , Locomoção/fisiologia , Córtex Motor/fisiologia , Lobo Parietal/fisiologia , Desempenho Psicomotor/fisiologia
3.
J Vis ; 22(10): 3, 2022 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-36069943

RESUMO

Patients with lesions of the parieto-occipital cortex typically misreach visual targets that they correctly perceive (optic ataxia). Although optic ataxia was described more than 30 years ago, distinguishing this condition from physiological behavior using kinematic data is still far from being an achievement. Here, combining kinematic analysis with machine learning methods, we compared the reaching performance of a patient with bilateral occipitoparietal damage with that of 10 healthy controls. They performed visually guided reaches toward targets located at different depths and directions. Using the horizontal, sagittal, and vertical deviation of the trajectories, we extracted classification accuracy in discriminating the reaching performance of patient from that of controls. Specifically, accurate predictions of the patient's deviations were detected after the 20% of the movement execution in all the spatial positions tested. This classification based on initial trajectory decoding was possible for both directional and depth components of the movement, suggesting the possibility of applying this method to characterize pathological motor behavior in wider frameworks.


Assuntos
Lateralidade Funcional , Desempenho Psicomotor , Braço , Ataxia , Fenômenos Biomecânicos , Lateralidade Funcional/fisiologia , Humanos , Aprendizado de Máquina , Desempenho Psicomotor/fisiologia
4.
PLoS One ; 17(9): e0273234, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36083888

RESUMO

According to the sequential stage model, the selection and the execution of a motor response are two distinct independent processes. Here, we propose a new adaptive paradigm for identifying the individual duration of the response preparatory period based on the motor reaction time (RT) data. The results are compared using the paradigm with constant values of the preparatory period. Two groups of participants performed on either an easy (Group 1) or a hard (Group 2) response selection task with two types of stimuli based on the preparatory period parameters: (1) stimuli with a constant preparatory period duration of 0 or 1200 ms and (2) stimuli with adaptive preparatory period durations. Our analysis showed an increase in the duration of the response selection process as a function of increasing task complexity when using both paradigms with constant and adaptive values of the preparatory period duration. We conclude that the adaptive paradigm proposed in the current paper has several important advantages over the constant paradigm in terms of measuring the response accuracy while being equally efficiently in capturing other critical response parameters.


Assuntos
Desempenho Psicomotor , Humanos , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia
5.
J Neurophysiol ; 128(3): 681-688, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35946802

RESUMO

Our perception of sensory events can be altered by action, but less is known about how our perception can be altered by action observation. For example, our ability to detect tactile stimuli is reduced when our limb is moving, and task-relevance and movement speed can alter such tactile detectability. During action observation, however, the relationship between tactile processing and such modulating factors is not known. Thus, the current study sought to explore tactile processing at a task-relevant location during the observation of reaching and grasping movements performed at different speeds. Specifically, participants observed videos of an anonymous model performing movements at a slow [i.e., peak velocity (PV): 155 mm/s], medium (i.e., PV: 547 mm/s), or fast speed (i.e., PV: 955 mm/s). To assess tactile processing, weak electrical stimuli of different amplitudes were presented to participants' right thumbs when the observed model was at their starting position and prior to any movement, or when the observed model's limb reached its PV. When observing slow movements, normalized perceptual thresholds were significantly lower/better than for the premovement stimulation time. These data suggest that the movement speed can modulate tactile processing, even when observing a movement. Furthermore, these findings provide seminal evidence for tactile facilitation at a task-relevant location during the observation of slow reaching and grasping movements (i.e., speeds associated with tactile exploration).NEW & NOTEWORTHY Previous work has highlighted the relationship between touch processing and movement speed during action, but the current study sought to understand this relationship during action observation of reaching and grasping movements. Here, we provide seminal evidence that tactile perceptual thresholds at the thumb are reduced compared with rest when observing the slowest movement speeds. Thus, tactile processing was facilitated at a task-relevant location during the observation of movements with speeds associated with tactile exploration.


Assuntos
Percepção do Tato , Tato , Objetivos , Força da Mão/fisiologia , Humanos , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Tato/fisiologia , Percepção do Tato/fisiologia
6.
Elife ; 112022 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-35969491

RESUMO

Multiple learning processes contribute to successful goal-directed actions in the face of changing physiological states, biomechanical constraints, and environmental contexts. Amongst these processes, implicit sensorimotor adaptation is of primary importance, ensuring that movements remain well-calibrated and accurate. A large body of work on reaching movements has emphasized how adaptation centers on an iterative process designed to minimize visual errors. The role of proprioception has been largely neglected, thought to play a passive role in which proprioception is affected by the visual error but does not directly contribute to adaptation. Here, we present an alternative to this visuo-centric framework, outlining a model in which implicit adaptation acts to minimize a proprioceptive error, the distance between the perceived hand position and its intended goal. This proprioceptive re-alignment model (PReMo) is consistent with many phenomena that have previously been interpreted in terms of learning from visual errors, and offers a parsimonious account of numerous unexplained phenomena. Cognizant that the evidence for PReMo rests on correlational studies, we highlight core predictions to be tested in future experiments, as well as note potential challenges for a proprioceptive-based perspective on implicit adaptation.


Assuntos
Desempenho Psicomotor , Percepção Visual , Adaptação Fisiológica/fisiologia , Retroalimentação Sensorial/fisiologia , Movimento/fisiologia , Propriocepção/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia
7.
Nat Commun ; 13(1): 4702, 2022 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-35948534

RESUMO

The interplay between task-relevant and task-irrelevant information may induce conflicts that impair behavioral performance, a.k.a. behavioral congruency effects. The neuronal mechanisms underlying behavioral congruency effects, however, are poorly understood. We recorded single unit activity in monkey prefrontal cortex using a task-switching paradigm and discovered a neuronal congruency effect (NCE) that is carried by target and distractor neurons which process target and distractor-related information, respectively. The former neurons provide more signal, the latter less noise in congruent compared to incongruent conditions, resulting in a better target representation. Such NCE is dominated by the level of congruency, and is not determined by the task rules the subjects used, their reaction times (RT), the length of the delay period, nor the response levels of the neurons. We propose that this NCE can explain behavioral congruency effects in general, as well as previous fMRI and EEG results in various conflict paradigms.


Assuntos
Macaca , Córtex Pré-Frontal , Animais , Humanos , Neurônios/fisiologia , Estimulação Luminosa/métodos , Córtex Pré-Frontal/fisiologia , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia
8.
Percept Mot Skills ; 129(5): 1362-1380, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35790415

RESUMO

Harmonious voluntary movements require efficiency in their planning and execution. Throughout middle childhood structural changes in the central nervous and musculoskeletal systems influence these processes and resultant motor behavior. In this study, we evaluated the characteristics of the motor planning and executing of aiming movements directed at targets located in different positions in space in children aged 7, 9, and 11 years. We divided 43 right-handed children, into three age groups and instructed them to perform aiming movements directed at targets using a stylus on a digital tablet. The children performed the movement with their dominant upper limbs from a starting point towards targets positioned ipsilaterally or contralaterally to this dominant limb. We analyzed temporal and spatial variables of motor performance. Younger (7-year-old) children made more errors in the initial movement direction and more frequently corrected their movements during task execution when compared to 9- and 11-year-old children who did not differ from each other. All age groups were similar in movement accuracy and precision. Movements toward contralateral targets were slower and more accurate than movements toward ipsilateral targets for all groups. These results show that performing aiming movements develop with the onset of middle childhood.


Assuntos
Lateralidade Funcional , Desempenho Psicomotor , Criança , Lateralidade Funcional/fisiologia , Mãos/fisiologia , Humanos , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Extremidade Superior
9.
Sci Rep ; 12(1): 11645, 2022 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-35804087

RESUMO

The emergence of the level 3 automated vehicles (L3 AVs) can enable drivers to be completely disengaged from driving and safely perform other non-driving related tasks, but sometimes their takeover of control of the vehicle is required. The takeover of control is an important human-machine interaction in L3 AVs. However, little research has focused on investigating the effect of gender on takeover performance. In order to fill this research gap, a driving simulator study with 76 drivers (33 females and 43 males) was conducted. The participants took over control from L3 AVs, and the timing and quality of takeover were measured. The results show that although there was no significant difference in most of the measurements adopted to quantify takeover performance between female and male. Gender did affect takeover performance slightly, with women exhibited slightly better performance than men. Compared to men, women exhibited a smaller percentage of hasty takeovers and slightly faster reaction times as well as slightly more stable operation of the steering wheel. The findings highlight that it is important for both genders to recognise they can use and interact with L3 AVs well, and more hands-on experience and teaching sessions could be provided to deepen their understanding of L3 AVs. The design of the car interiors of L3 AVs should also take into account gender differences in the preferences of users for different non-driving related tasks.


Assuntos
Condução de Veículo , Veículos Autônomos , Desempenho Psicomotor , Condução de Veículo/psicologia , Feminino , Humanos , Masculino , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Fatores Sexuais
10.
J Neurophysiol ; 128(3): 543-555, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35894437

RESUMO

Even simple actions like opening a door require integration/binding and flexible reactivation of different motor elements. Yet, the neural mechanisms underlying the processing of such "embedded response plans" are largely elusive, despite theoretical frameworks, such as the theory of event coding, describing the involved cognitive processes. In a sample of n = 40 healthy participants, we combine time-frequency decomposition and various beamforming methods to examine the neurophysiological dynamics of such action plans, with special emphasis on the interplay of theta and beta frequency activity during the processing of these plans. We show that the integration and rule-guided reactivation of embedded response plans is modulated by a complex interplay of theta and beta activity. Pretrial beta-band activity (BBA) is related to different functional neuroanatomical structures that are activated in a consecutive fashion. Enhanced preparatory activity is positively associated with higher binding-related BBA in the precuneus/parietal areas, indicating that activity in the precuneus/parietal cortex facilitates the execution of an embedded action sequence. Increased preparation subsequently leads to reduced working memory retrieval demands. A cascading pattern of interactions between pretrial and within-trial activity indicates the importance of preparatory brain activity. The study shows that there are multiple roles of beta and theta oscillations associated with different functional neuroanatomical structures during the integration and reactivation of motor elements during actions.NEW & NOTEWORTHY Even simple actions like opening a door require integration/binding and flexible reactivation of different motor elements. Yet, the neural mechanisms underlying the processing of such "embedded response plans" are largely elusive. The study shows that there are multiple roles of beta and theta oscillations associated with different functional neuroanatomical structures during the integration and reactivation of motor elements during actions.


Assuntos
Ritmo beta , Lobo Frontal , Lobo Parietal , Desempenho Psicomotor , Ritmo Teta , Ritmo beta/fisiologia , Eletroencefalografia , Lobo Frontal/fisiologia , Humanos , Memória de Curto Prazo/fisiologia , Lobo Parietal/fisiologia , Desempenho Psicomotor/fisiologia , Ritmo Teta/fisiologia
11.
J Neurophysiol ; 128(3): 445-454, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35822745

RESUMO

Vision plays a vital role in locomotor learning, providing feedback information to correct movement errors, and feedforward information to inform learned movement plans. Gaze behavior, or the distribution of fixation locations, can quantify how visual information is used during the motor learning process. How gaze behavior adapts during motor learning and in response to changing motor performance is poorly understood. This study examines if and how an individual's gaze behavior adapts during a sequence learning, target stepping task. We monitored the gaze behavior of 12 healthy young adults while they walked on a treadmill and attempted to precisely step on moving targets that were separated by variable distances (80%, 100%, and 120% of preferred step length). Participants completed a total of 11 trial blocks of 102 steps each. We hypothesized that both mean fixation distance would increase (participants would look farther ahead), and step error would decrease with experience. Following practice, participants significantly increased their fixation distance (P < 0.001) by 0.27 ± 0.18 steps and decreased their step error (P < 0.001) by 4.0 ± 1.7 cm, supporting our hypothesis. Our results suggest that early in the learning process, participants gaze behavior emphasized gathering visual information necessary for feedback motor control. As motor performance improved with experience, participants shifted their gaze fixation farther ahead placing greater emphasis on the visual information used for feedforward motor control. These findings provide important information about how gaze behavior changes in parallel with improvements in walking performance.NEW & NOTEWORTHY People consistently vary how they use visual information to inform walking. However, what drives this variation and how sampled visual information changes with locomotor learning is not well understood. Here, we find that gaze fixation locations moved farther ahead while step error decreases as participants practice a target stepping task. The results suggest that participants increasingly used a feedforward locomotor control strategy with practice.


Assuntos
Fixação Ocular , Desempenho Psicomotor , Humanos , Aprendizagem , Desempenho Psicomotor/fisiologia , Visão Ocular , Caminhada/fisiologia , Adulto Jovem
12.
J Neurophysiol ; 128(3): 494-510, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35858112

RESUMO

Humans can produce "express" (∼100 ms) arm muscle responses that are inflexibly locked in time and space to visual target presentations, consistent with subcortical visuomotor transformations via the tecto-reticulo-spinal pathway. These express visuomotor responses are sensitive to explicit cue-driven expectations, but it is unclear at what stage of sensory-to-motor transformation such modulation occurs. Here, we recorded electromyographic activity from shoulder muscles as participants reached toward one of four virtual targets whose physical location was partially predictable from a symbolic cue. In an experiment in which targets could be veridically reached, express responses were inclusive of the biomechanical requirements for reaching the cued locations and not systematically modulated by cue validity. In a second experiment, movements were restricted to the horizontal plane so that the participants could perform only rightward or leftward reaches, irrespective of target position on the vertical axis. Express muscle responses were almost identical for targets that were validly cued in the horizontal direction, regardless of cue validity in the vertical dimension. Together, these findings suggest that the cue-induced enhancements of express responses are dominated by effects at the level of motor plans and not solely via facilitation of early visuospatial target processing. Notably, direct corticotectal and corticoreticular projections exist that are well-placed to modulate prestimulus motor preparation state in subcortical circuits. Our results could reflect a neural mechanism by which contextually relevant motor responses to compatible visual inputs are rapidly released via subcortical circuits that are sufficiently along the sensory-to-motor continuum.NEW & NOTEWORTHY Express arm muscle responses to suddenly appearing visual targets for reaching rapid have been attributed to the tecto-reticulo-spinal pathway in humans. We demonstrate that symbolic cues before target presentation can modulate such express arm muscle responses compatibly with the biomechanics of the cued reaching direction and the cue validity. This implies cortically mediated modulation of one or more sensorimotor transformation nodes of the subcortical express pathway.


Assuntos
Sinais (Psicologia) , Desempenho Psicomotor , Braço/fisiologia , Humanos , Movimento/fisiologia , Músculos , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia
13.
Neuropsychologia ; 174: 108333, 2022 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-35842019

RESUMO

Action monitoring is crucial to the successful execution of an action and understanding the actions of others. It is often impaired due to brain lesions, in particular after stroke. This systematic review aims to map the literature on the neurophysiological correlates of action monitoring in patients with brain lesions. Eighteen studies were identified and divided into two groups: studies on monitoring of one's own actions and studies on monitoring of the actions of others. The first group included EEG studies on monitoring of self-performed erroneous and correct actions. Impaired error detection (decreased error-related negativity) was observed in patients with lesions in the performance-monitoring network, as compared to healthy controls. Less consistent results were shown for error positivity and behavioral error monitoring performance. The second group of studies on monitoring of others' actions reported decreased mu frequency suppression, impaired readiness potential in the affected hemisphere and decreased EEG indices of error observation (observed error positivity and theta power) in stroke patients. As a whole, these results indicate distinct patterns of impaired neurophysiological activity related to monitoring one's own versus others' actions in patients with brain lesions. EEG recordings of this dissociation in the same patients might be a useful index of motor recovery, and therefore, potentially also beneficial in rehabilitation protocols.


Assuntos
Lesões Encefálicas , Acidente Vascular Cerebral , Encéfalo , Eletroencefalografia/métodos , Humanos , Desempenho Psicomotor/fisiologia , Acidente Vascular Cerebral/complicações
14.
Trends Cogn Sci ; 26(9): 767-781, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35803832

RESUMO

Mirror neurons (MNs) were first described in a seminal paper in 1992 as a class of monkey premotor cells discharging during both action execution and observation. Despite their debated origin and function, recent studies in several species, from birds to humans, revealed that beyond MNs properly so called, a variety of cell types distributed among multiple motor, sensory, and emotional brain areas form a 'mirror mechanism' more complex and flexible than originally thought, which has an evolutionarily conserved role in social interaction. Here, we trace the current limits and envisage the future trends of this discovery, showing that it inspired translational research and the development of new neurorehabilitation approaches, and constitutes a point of no return in social and affective neuroscience.


Assuntos
Neurônios-Espelho , Córtex Motor , Encéfalo/fisiologia , Mapeamento Encefálico , Humanos , Neurônios-Espelho/fisiologia , Córtex Motor/fisiologia , Desempenho Psicomotor/fisiologia
15.
Elife ; 112022 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-35894379

RESUMO

To generate the next eye movement, oculomotor circuits take into consideration the physical salience of objects in view and current behavioral goals, exogenous and endogenous influences, respectively. However, the interactions between exogenous and endogenous mechanisms and their dynamic contributions to target selection have been difficult to resolve because they evolve extremely rapidly. In a recent study (Salinas et al., 2019), we achieved the necessary temporal precision using an urgent variant of the antisaccade task wherein motor plans are initiated early and choice accuracy depends sharply on when exactly the visual cue information becomes available. Empirical and modeling results indicated that the exogenous signal arrives ∼80 ms after cue onset and rapidly accelerates the (incorrect) plan toward the cue, whereas the informed endogenous signal arrives ∼25 ms later to favor the (correct) plan away from the cue. Here, we scrutinize a key mechanistic hypothesis about this dynamic, that the exogenous and endogenous signals act at different times and independently of each other. We test quantitative model predictions by comparing the performance of human participants instructed to look toward a visual cue or away from it under high urgency. We find that, indeed, the exogenous response is largely impervious to task instructions; it simply flips its sign relative to the correct choice, and this largely explains the drastic differences in psychometric performance between the two tasks. Thus, saccadic choices are strongly dictated by the alignment between salience and behavioral goals.


Assuntos
Movimentos Oculares , Movimentos Sacádicos , Humanos , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia
16.
PLoS One ; 17(7): e0271164, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35819966

RESUMO

Shaping one owns actions by observing others' actions is driven by the deep-rooted mechanism of perception-action coupling. It typically occurs automatically, expressed as for example the unintentional synchronization of reaction times in interactive games. Theories on perception-action coupling highlight its benefits such as the joint coordination of actions to cooperatively perform tasks properly, the learning of novel actions from others, and the bonding with likable others. However, such functional aspects and how they shape perception-action coupling have never been compared quantitatively. Here we tested a total of hundred-fifteen participants that played a stimulus-response task while, in parallel, they observed videos of agents that played the exact same task several milliseconds in advance. We compared to what degree the reaction times of actions of agents, who varied their behavior in terms of functionality and likability in preceding prisoner dilemma games and quizzes, shape the reaction times of human test participants. To manipulate functionality and likability, we varied the predictability of cooperative behavior and correctness of actions of agents, respectively, resulting in likable (cooperative), dislikable (uncooperative), functional (correct actions), and dysfunctional (incorrect actions) agents. The results of three experiments showed that the participants' reaction times correlated most with the reaction times of agents that expressed functional behavior. However, the likability of agents had no effects on reaction time correlations. These findings suggest that, at least in the current computer task, participants are more likely to adopt the timing of actions from people that perform correct actions than from people that they like.


Assuntos
Comportamento Cooperativo , Desempenho Psicomotor , Computadores , Humanos , Dilema do Prisioneiro , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia
17.
Proc Natl Acad Sci U S A ; 119(28): e2122395119, 2022 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-35867763

RESUMO

To understand the cortical neuronal dynamics behind movement generation and control, most studies have focused on tasks where actions were planned and then executed using different instances of visuomotor transformations. However, to fully understand the dynamics related to movement control, one must also study how movements are actively inhibited. Inhibition, indeed, represents the first level of control both when different alternatives are available and only one solution could be adopted and when it is necessary to maintain the current position. We recorded neuronal activity from a multielectrode array in the dorsal premotor cortex (PMd) of monkeys performing a countermanding reaching task that requires, in a subset of trials, them to cancel a planned movement before its onset. In the analysis of the neuronal state space of PMd, we found a subspace in which activities conveying temporal information were confined during active inhibition and position holding. Movement execution required activities to escape from this subspace toward an orthogonal subspace and, furthermore, surpass a threshold associated with the maturation of the motor plan. These results revealed further details in the neuronal dynamics underlying movement control, extending the hypothesis that neuronal computation confined in an "output-null" subspace does not produce movements.


Assuntos
Atividade Motora , Córtex Motor , Neurônios , Desempenho Psicomotor , Animais , Macaca mulatta , Atividade Motora/fisiologia , Córtex Motor/citologia , Córtex Motor/fisiologia , Neurônios/fisiologia , Desempenho Psicomotor/fisiologia
18.
PLoS One ; 17(6): e0269557, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35687556

RESUMO

Embodied and grounded cognition theories state that cognitive processing is built upon sensorimotor systems. In the context of numerical cognition, support to this framework comes from the interactions between numerical processing and the hand actions of reaching and grasping documented in skilled adults. Accordingly, mechanisms for the processing of object size and location during reach and grasp actions might scaffold the development of mental representations of numerical magnitude. The present study exploited motor adaptation to test the hypothesis of a functional overlap between neurocognitive mechanisms of hand action and numerical processing. Participants performed repetitive grasping of an object, repetitive pointing, repetitive tapping, or passive viewing. Subsequently, they performed a symbolic number comparison task. Importantly, hand action and number comparison were functionally and temporally dissociated, thereby minimizing context-based effects. Results showed that executing the action of pointing slowed down the responses in number comparison. Moreover, the typical distance effect (faster responses for numbers far from the reference as compared to close ones) was not observed for small numbers after pointing, while it was enhanced by grasping. These findings confirm the functional link between hand action and numerical processing, and suggest new hypotheses on the role of pointing as a meaningful gesture in the development and embodiment of numerical skills.


Assuntos
Mãos , Desempenho Psicomotor , Adulto , Cognição , Mãos/fisiologia , Força da Mão/fisiologia , Humanos , Desempenho Psicomotor/fisiologia
19.
Int J Psychophysiol ; 179: 21-29, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35753563

RESUMO

Taking a short midday nap has been associated with higher alertness and better cognitive task performance. Yet, the mechanisms associated with nap-dependent performance enhancement are unclear. The current study was conducted to explore the impact of physiological arousal during cognitive task and sleep architecture during a pre-task nap on post-nap behavioral outcomes. A within-subjects design (N = 18) was employed, in which participants either took a nap or remained awake for 40 min during the post-lunch period. The psychomotor vigilance test (PVT) and n-back task were administered to assess sustained attention and working memory, respectively, with each task including one block of easy trials and one block of difficult trials. Results showed that a short midday nap improved sustained attention but not working memory. In addition, a midday nap induced lower physiological arousal during the performance on both cognitive tasks, with relatively higher delta and lower beta activity. The relative power of theta and alpha were positively correlated with performance on the easy PVT, whereas the alpha power was negatively correlated with performance on the difficult PVT, and the theta power was negatively correlated with reaction speed in the n-back task regardless of the task difficulty. Meanwhile, the shorter total sleep time and longer time of wake after sleep onset were associated with the faster overall reaction speed in PVT easy trials. These findings suggested that both changes in physiological arousal and sleep variables might account for changes in task performance after a short midday nap.


Assuntos
Desempenho Psicomotor , Sono , Atenção/fisiologia , Humanos , Memória de Curto Prazo/fisiologia , Desempenho Psicomotor/fisiologia , Tempo de Reação , Sono/fisiologia , Privação do Sono , Vigília/fisiologia
20.
PLoS Comput Biol ; 18(6): e1010192, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35679316

RESUMO

The separation of distinct motor memories by contextual cues is a well known and well studied phenomenon of feedforward human motor control. However, there is no clear evidence of such context-induced separation in feedback control. Here we test both experimentally and computationally if context-dependent switching of feedback controllers is possible in the human motor system. Specifically, we probe visuomotor feedback responses of our human participants in two different tasks-stop and hit-and under two different schedules. The first, blocked schedule, is used to measure the behaviour of stop and hit controllers in isolation, showing that it can only be described by two independent controllers with two different sets of control gains. The second, mixed schedule, is then used to compare how such behaviour evolves when participants regularly switch from one task to the other. Our results support our hypothesis that there is contextual switching of feedback controllers, further extending the accumulating evidence of shared features between feedforward and feedback control.


Assuntos
Sinais (Psicologia) , Desempenho Psicomotor , Retroalimentação , Retroalimentação Sensorial/fisiologia , Humanos , Aprendizagem/fisiologia , Desempenho Psicomotor/fisiologia
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