Effect of the Menstrual Cycle on Electroencephalogram Alpha and Beta Bands During Motor Imagery and Action Observation.

Female sex steroids (FSS) can affect the motor system, modulating motor cortex excitability as well as performance in dexterity and coordination tasks. However, it has not yet been explored whether FSS affects the cognitive components of motor behavior. Mu is a sensorimotor rhythm observed by electroencephalography (EEG) in alpha (8-12 Hz) and beta (15-30 Hz) frequency bands in practices such as motor imagery (MI) and action observation (AO). This rhythm represents a window for studying the activity of neural circuits involved in motor cognition. Herein we investigated whether the alpha-mu and beta-mu power in the sensorimotor region (C3 and C4, hypothesis-driven approach) and the alpha and beta power over frontal, parietal, and occipital regions (data-driven approach) are modulated differently in the menstrual, follicular, and luteal phases of menstrual cycles in right-handed dominant women. To do so, these women underwent MI and AO in the three menstrual cycle phases. The spectral activity of the cortical regions for the alpha and beta bands were compared between phases of the menstrual cycle and a correlation analysis was also performed in relation to estrogen and progesterone levels. For the hypothesis-based approach, beta-mu event-related desynchronization (ERD) was significantly stronger in the C3 channel in the follicular phase than in the menstrual and luteal phases. For the data-driven approach, beta ERD during MI was higher in the follicular phase than in the menstrual and luteal phases in the frontal region. These findings suggest the effect of FSS on executive movement control. No effect of menstrual cycle phases was observed in cortical areas investigated during OA, but alpha and beta bands correlated positively with the follicular phase plasma estradiol level. Thus, the attenuation of alpha and beta bands referring to mirror neuron activities appears to be associated with inhibition of cortical activity when estradiol levels are lower, improving cognitive processing of motor action.

Effects of action observation training on the walking ability of patients post stroke: a systematic review.

OBJECTIVE: To determine the effect of action observation (AO) training on the walking ability of patients post stroke. METHODS: MEDLINE, CINAHL, EMBASE and PEDro were searched systematically for human studies written in English up to August 31st 2021. Two authors screened titles and abstracts against predefined inclusion criteria; a third author resolved discrepancies. Data were analyzed through qualitative synthesis. Articles evaluating the effects of AO training on the walking ability of patients post stroke were included. Methodological quality was assessed using the PEDro scale. RESULTS: From first search that included 1,578 studies, 7 were included in this review. According to the PEDro scale, most of the studies exhibited a methodological quality between Good and Fair (N = 6). Most of the studies applied a protocol based on a 30-minute training session applied 3 to 5 times per week over a 4-week period (N = 5). Using clinical measures and gait parameters, all studies confirmed the beneficial effects of AO training on walking ability. However, the effects of AO training on walking ability were not confirmed at the long-term follow-up. CONCLUSIONS: AO training has a positive effect on the walking ability of patients post stroke. Additional studies are needed to confirm these results across the entire spectrum of patient's post stoke including long-term clinical effects.Implications for RehabilitationAction observation training can have potentially positive effects on the walking ability of stroke patients.Clinical measurements (10-meter walk test) and gait parameters (stride length and gait speed) could be used to assess the effect of action observation training on walking ability.The patient's concentration is an important factor to consider when applying observational training.

Implicit action prediction constrains observed biological action reconstruction.

Voluntary movements include a predictive control of the sensory-motor consequences of executed or observed actions. The motor system predicts further steps of actions relying on its pure observation. This study seeks to disclose the interference of an implicit motor prediction effect during actions reconstruction. Videos of human actions directed to objects were presented to volunteers. Subsequently, they combined four static frames of those videos randomly arranged on the screen. Such combination could be chronological (from the beginning to the end of the action) or reverse (from the end to the beginning of the action). The observed actions were also biological (human movement) or non-biological (movement of objects). The grasping began with the actor's hand in a resting position over a table (Experiment I), or with his hand in contact with the object (Experiment II). In the first experiment, participants presented lower accuracy in the biological condition rearranging in chronological order. In the second experiment, however, the accuracy was lower in reverse order. The interpretation of such results is that the implicit predictive mechanisms interfered in the rearrangement of the frames. As an example: the expected movement after a grasping action whose outcome is capping a bottle would be the withdrawal of the hand. Therefore, combining frames of a recent seen action, volunteers present less accuracy if the first frame to be placed is counterintuitive.

Single session of action observation in choice reaction time in healthy children

Abstract Aim: Learning by action observation (AO) is a fundamental cognitive ability existing from birth either in live or in the video. However, the specific AO training, in live or in the video, can influence decision making and motor planning in healthy children? This study aimed to evaluate if a single session of both practices (live and video) modifies the choice reaction time during reaching tasks in healthy children. Methods: This is a cross-sectional and randomized study with 22 children aged 6 to 8 years. We measured the choice reaction time (CRT) by electromyography at baseline and after both practices. Data were analyzed using Friedman and posthoc Dunn non-parametric tests for each age group individually as well as all ages combined. Kurtosis analysis was performed to assess data variability. Results: Significant decrease in CRT was observed after action observation in the video in 8-year-olds. Also, we observed choice reaction time variability reduction in 8-year-olds after both practices compared to that at baseline. Conclusion: A decrease in CRT was observed after the single session of action observation in the video in 8-year-olds. Additionally, there was a reduced variability in CRT after performing both practices in the same age group.

Action observation combined with gait training to improve gait and cognition in elderly with mild cognitive impairment A randomized controlled trial.

Owing to advancement of medical technology and current knowledge, the population has a longer life expectancy, leading to an increase in the proportion of elderly. OBJECTIVE: The study aimed to investigate the effect of action observation (AO) combined with gait training on gait and cognition in elderly with mild cognitive impairment (MCI). METHODS: Thirty-three participants were randomly allocated to action observation with gait training (AOGT), gait training (GT), and control (CT) groups. The AOGT and GT groups received a program of observation and gait training protocol with the same total duration of 65 min for 12 sessions. For the observation, the AGOT group watched a video of normal gait movement, while the GT group watched an abstract picture and the CT group received no training program. All participants were assessed for gait parameters during single- and dual-tasks using an electronic gait mat system and were assessed for cognitive level using the Montreal Cognitive Assessment (MoCA) at baseline, after training and at 1-month follow-up. RESULTS: The results showed that the AOGT group had significant improvements in gait speeds during single- and dual-tasks, as well as better MoCA score, while the GT group had significant improvement only in gait speed. CONCLUSION: The adjunct treatment of AO with gait training provides greater benefits for both gait and cognitive performances in elderly with MCI.

Com o avanço da tecnologia médica e do conhecimento atual, a população tem uma expectativa de vida mais longa, levando a um aumento na proporção de idosos. OBJETIVO: O estudo teve como objetivo investigar o efeito da observação de ação (AO) combinada com o treinamento da marcha na marcha e cognição em idosos com comprometimento cognitivo leve (CCL). MÉTODOS: Trinta e três participantes foram alocados aleatoriamente para observação de ação com grupos de treinamento de marcha (AOGT), treinamento de marcha (GT) e controle (CT). Os grupos AOGT e GT receberam um programa de observação e protocolo de treinamento de marcha com a mesma duração total de 65 minutos por 12 sessões. Na observação, o grupo AGOT assistiu a um vídeo de movimento normal da marcha, enquanto o grupo GT assistiu a uma figura abstrata e o grupo CT não recebeu nenhum programa de treinamento. Todos os participantes foram avaliados quanto aos parâmetros da marcha durante tarefas simples e duplas, utilizando um sistema eletrônico de esteira da marcha e avaliados quanto ao nível cognitivo, utilizando a Avaliação Cognitiva de Montreal (MoCA) na linha de base, após o treinamento e 1 mês de acompanhamento. RESULTADOS: Os resultados mostraram que o grupo AOGT apresentou melhorias significativas nas velocidades da marcha durante tarefas simples e duplas, além do escore MoCA, enquanto o grupo GT teve melhora significativa apenas na velocidade da marcha. CONCLUSÃO: O tratamento adjunto da AO com o treinamento da marcha proporciona maiores benefícios tanto do desempenho da marcha quanto do desempenho cognitivo em idosos com CCL.

Action observation combined with gait training to improve gait and cognition in elderly with mild cognitive impairment A randomized controlled trial / Observação da ação e treinamento da marcha para melhorar a marcha e a cognição em idosos com comprometimento cognitivo leve: um estudo controlado randomizado

Abstract. Owing to advancement of medical technology and current knowledge, the population has a longer life expectancy, leading to an increase in the proportion of elderly. Objective: The study aimed to investigate the effect of action observation (AO) combined with gait training on gait and cognition in elderly with mild cognitive impairment (MCI). Methods: Thirty-three participants were randomly allocated to action observation with gait training (AOGT), gait training (GT), and control (CT) groups. The AOGT and GT groups received a program of observation and gait training protocol with the same total duration of 65 min for 12 sessions. For the observation, the AGOT group watched a video of normal gait movement, while the GT group watched an abstract picture and the CT group received no training program. All participants were assessed for gait parameters during single- and dual-tasks using an electronic gait mat system and were assessed for cognitive level using the Montreal Cognitive Assessment (MoCA) at baseline, after training and at 1-month follow-up. Results: The results showed that the AOGT group had significant improvements in gait speeds during single- and dual-tasks, as well as better MoCA score, while the GT group had significant improvement only in gait speed. Conclusion: The adjunct treatment of AO with gait training provides greater benefits for both gait and cognitive performances in elderly with MCI.

Resumo. Com o avanço da tecnologia médica e do conhecimento atual, a população tem uma expectativa de vida mais longa, levando a um aumento na proporção de idosos. Objetivo: O estudo teve como objetivo investigar o efeito da observação de ação (AO) combinada com o treinamento da marcha na marcha e cognição em idosos com comprometimento cognitivo leve (CCL). Métodos: Trinta e três participantes foram alocados aleatoriamente para observação de ação com grupos de treinamento de marcha (AOGT), treinamento de marcha (GT) e controle (CT). Os grupos AOGT e GT receberam um programa de observação e protocolo de treinamento de marcha com a mesma duração total de 65 minutos por 12 sessões. Na observação, o grupo AGOT assistiu a um vídeo de movimento normal da marcha, enquanto o grupo GT assistiu a uma figura abstrata e o grupo CT não recebeu nenhum programa de treinamento. Todos os participantes foram avaliados quanto aos parâmetros da marcha durante tarefas simples e duplas, utilizando um sistema eletrônico de esteira da marcha e avaliados quanto ao nível cognitivo, utilizando a Avaliação Cognitiva de Montreal (MoCA) na linha de base, após o treinamento e 1 mês de acompanhamento. Resultados: Os resultados mostraram que o grupo AOGT apresentou melhorias significativas nas velocidades da marcha durante tarefas simples e duplas, além do escore MoCA, enquanto o grupo GT teve melhora significativa apenas na velocidade da marcha. Conclusão: O tratamento adjunto da AO com o treinamento da marcha proporciona maiores benefícios tanto do desempenho da marcha quanto do desempenho cognitivo em idosos com CCL.

Cerebral Dynamics during the Observation of Point-Light Displays Depicting Postural Adjustments.

Objective: As highly social creatures, human beings rely part of their skills of identifying, interpreting, and predicting the actions of others on the ability of perceiving biological motion. In the present study, we aim to investigate the electroencephalographic (EEG) cerebral dynamics involved in the coding of postural control and examine whether upright stance would be codified through the activation of the temporal-parietal cortical network classically enrolled in the coding of biological motion. Design: We registered the EEG activity of 12 volunteers while they passively watched point light displays (PLD) depicting quiet stable (QB) and an unstable (UB) postural situations and their respective scrambled controls (QS and US). In a pretest, 13 volunteers evaluated the level of stability of our two biological stimuli through a stability scale. Results: Contrasting QB vs. QS revealed a typical ERP difference in the right temporal-parietal region at an early 200-300 ms time window. Furthermore, when contrasting the two biological postural conditions, UB vs. QB, we found a higher positivity in the 400-600 ms time window for the UB condition in central-parietal electrodes, lateralized to the right hemisphere. Conclusions: These results suggest that PLDs depicting postural adjustments are coded in the brain as biological motion, and that their viewing recruit similar networks with those engaged in postural stability control. Additionally, higher order cognitive processes appear to be engaged in the identification of the postural instability level. Disentangling the EEG dynamics during the observation of postural adjustments could be very useful for further understanding the neural mechanisms underlying postural control.

The Relative Influence of Goal and Kinematics on Corticospinal Excitability Depends on the Information Provided to the Observer.

Viewing a person perform an action activates the observer's motor system. Whether this phenomenon reflects the action's kinematics or its final goal remains a matter of debate. One alternative to this apparent controversy is that the relative influence of goal and kinematics depends on the information available to the observer. Here, we addressed this possibility. For this purpose, we measured corticospinal excitability (CSE) while subjects viewed 3 different grasping actions with 2 goals: a large and a small object. Actions were directed to the large object, the small object, or corrected online in which case the goal switched during the movement. We first determined the kinematics and dynamics of the 3 actions during execution. This information was used in 2 other experiments to measure CSE while observers viewed videos of the same actions. CSE was recorded prior to movement onset and at 3 time points during the observed action. To discern between goal and kinematics, information about the goal was manipulated across experiments. We found that the goal influenced CSE only when its identity was known before movement onset. In contrast, a kinematic modulation of CSE was observed whether or not information regarding the goal was provided.

Throwing the banana away and keeping the peel: neuroelectric responses to unexpected but physically feasible action endings.

Integrative semantic processing and mirror-neuron system activation in response to incongruence detection during action observation have so far been investigated only through paradigms that involve unfeasible action endings, introduction of extraneous objects or synthetic pictures. The ecological validity of the reported effects, particularly modulation of the N400 event-related potential (ERP), therefore remains questionable. To address this shortcoming, we investigated the ERPs evoked by physically feasible and naturalistic but unexpected action endings. We hypothesized that in comparison to existing work our more realistic scenarios would elicit slower processing, due to engagement of deeper analysis as opposed to fast detection based on automatic processes. ERPs were recorded in 14 healthy participants in response to 60 sequences, each containing three pictures, the last of which could be an expected or unexpected action ending. The N400 was larger for the first image compared to the others, and the LPP was enhanced for unexpected endings. Source localization implicated anterior fronto-temporal and temporo-parietal junction regions in generation of these potentials. Our findings challenge the view that the N400 universally indices verbal and action-perception incongruence detection, and point to situation-contingent effects which, in the case of subtle violations, are reflected in later activity components, speculatively reflecting recourse to the "mentalizing" system.

Je pense donc je fais: transcranial direct current stimulation modulates brain oscillations associated with motor imagery and movement observation.

Motor system neural networks are activated during movement imagery, observation and execution, with a neural signature characterized by suppression of the Mu rhythm. In order to investigate the origin of this neurophysiological marker, we tested whether transcranial direct current stimulation (tDCS) modifies Mu rhythm oscillations during tasks involving observation and imagery of biological and non-biological movements. We applied tDCS (anodal, cathodal, and sham) in 21 male participants (mean age 23.8 ± 3.06), over the left M1 with a current of 2 mA for 20 min. Following this, we recorded the EEG at C3, C4, and Cz and surrounding C3 and C4 electrodes. Analyses of C3 and C4 showed significant effects for biological vs. non-biological movement (p = 0.005), and differential hemisphere effects according to the type of stimulation (p = 0.04) and type of movement (p = 0.02). Analyses of surrounding electrodes revealed significant interaction effects considering type of stimulation and imagery or observation of biological or non-biological movement (p = 0.03). The main findings of this study were (1) Mu desynchronization during biological movement of the hand region in the contralateral hemisphere after sham tDCS; (2) polarity-dependent modulation effects of tDCS on the Mu rhythm, i.e., anodal tDCS led to Mu synchronization while cathodal tDCS led to Mu desynchronization during movement observation and imagery (3) specific focal and opposite inter-hemispheric effects, i.e., contrary effects for the surrounding electrodes during imagery condition and also for inter-hemispheric electrodes (C3 vs. C4). These findings provide insights into the cortical oscillations during movement observation and imagery. Furthermore, it shows that tDCS can be highly focal when guided by a behavioral task.