scholarly journals Implicit visual sensitivity towards slim versus overweight bodies modulates motor resonance in the primary motor cortex: A tDCS study

2020 ◽  
Author(s):  
Stergios Makris ◽  
Valentina Cazzato
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Action Observation ◽  
Video Clip ◽  
Normal Weight ◽  
Visual Sensitivity ◽  
Motor Resonance ◽  
Action Observation Network ◽  
Cathodal Tdcs ◽  
Overweight Group

AbstractMotor resonance (MR) can be influenced by individual differences and similarity in the physical appearance between the actor and observer. Recently, we reported that action simulation is modulated by an implicit visual sensitivity towards normal-weight compared with overweight bodies. Furthermore, recent research has suggested the existence of an action observation network responsible for MR, with limited evidence whether the primary motor cortex (M1) is part of this. We expanded our previous findings with regards to the role of an implicit normal-weight-body preference in the MR mechanism. At the same time, we tested the functional relevance of M1 to MR, by using a transcranial direct current stimulation (tDCS) protocol. Seventeen normal-weight and 17 overweight participants were asked to observe normal-weight or overweight actors reaching and grasping a light or heavy cube, and then, at the end of each video-clip to indicate the correct cube weight. Before the task, all participants received 15 min of sham or cathodal tDCS over the left M1. Measures of anti-fat attitudes were also collected. During sham tDCS, all participants were better in simulating the actions performed by normal-weight compared with overweight models. Surprisingly, cathodal tDCS selectively improved the ability in the overweight group to simulate actions performed by the overweight models. This effect was not associated with scores of fat phobic attitudes or implicit anti-fat bias. Our findings are discussed in the context of relevance of M1 to MR and its social modulation by anti-fat attitudes.

scholarly journals Uncertainty in contextual and kinematic cues jointly modulates motor resonance in primary motor cortex

2019 ◽  
Vol 121 (4) ◽  
pp. 1451-1464 ◽  
Author(s):  
Andreea Loredana Cretu ◽  
Kathy Ruddy ◽  
Maria Germann ◽  
Nicole Wenderoth
Keyword(s):  
Motor Cortex ◽  
Neural Activity ◽  
Primary Motor Cortex ◽  
Contextual Information ◽  
Action Observation ◽  
Motor Resonance ◽  
Movement Kinematics ◽  
Corticomotor Excitability ◽  
Movement Observation ◽  
Motor Representations

Contextual information accompanying others’ actions modulates “motor resonance”, i.e., neural activity within motor areas that is elicited by movement observation. One possibility is that we weigh and combine such information in a Bayesian manner according to their relative uncertainty. Therefore, contextual information becomes particularly useful when others’ actions are difficult to discriminate. It is unclear, however, whether this uncertainty modulates the neural activity in primary motor cortex (M1) during movement observation. Here, we applied single-pulse transcranial magnetic stimulation (TMS) while subjects watched different grasping actions. We operationalized motor resonance as grip-specific modulation of corticomotor excitability measured in the index (FDI) versus the little finger abductor (ADM). We experimentally modulated either the availability of kinematic information ( experiment 1) or the reliability of contextual cues ( experiment 2). Our results indicate that even in the absence of movement kinematics, reliable contextual information is enough to trigger significant muscle-specific corticomotor excitability changes in M1, which are strongest when both kinematics and contextual information are available. These findings suggest that bottom-up mechanisms that activate motor representations as a function of the observed kinematics and top-down mechanisms that activate motor representations associated with arbitrary cues converge in M1. NEW & NOTEWORTHY Our study reveals new neurophysiological insights in support of the Bayesian account of action observation by showing that “motor resonance”, i.e., neural activity evoked by observing others’ actions, incorporates the uncertainty related to both contextual (prior beliefs) and kinematic (sensory evidence) cues. Notably, we show that muscle-specific modulation of M1 is strongest when context and movement kinematics are available, and it can be elicited even in the absence of movement kinematics.

scholarly journals Reward modulates behaviour and neural responses in motor cortex during action observation

2019 ◽  
Author(s):  
Andreea Loredana Cretu ◽  
Rea Lehner ◽  
Rafael Polania ◽  
Nicole Wenderoth
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Response Times ◽  
Contextual Information ◽  
Action Observation ◽  
Neural Responses ◽  
Motor Resonance ◽  
Neural Representations ◽  
Attentional Engagement ◽  
Physiological Outcomes

AbstractTranscranial magnetic stimulation (TMS) studies demonstrated that observing the actions of other individuals leads to action-specific facilitation of primary motor cortex (M1) (i.e., “motor resonance”). Motor resonance is modulated by contextual information accompanying others’ actions, however, it is currently unknown whether action value influences behavioural and physiological outcomes during action observation in humans. Here we tested whether response times (RT) and muscle-specific changes of M1 excitability are modulated by the value an observer assigns to the action executed by another agent and whether this effect can be distinguished from attentional engagement. We show that observing highly-valued actions leads to a significant decrease in RT variability and a significant strengthening of action-specific neural representations in M1. This “sharpening” of behavioural and neural responses was observed over and beyond a control task requiring similar attentional engagement but did not include any rewards. Our finding that reward influences action specific representations in human M1 even if no motor response is required is new, suggesting that reward influences the transformation of action stimuli from the perceptual to the motor domain. We suggest that premotor areas are important for mediating the observed effect, most likely by optimizing grasp-specific PMv-M1 interactions which cause muscular facilitation patterns in M1 to be more distinct for rewarded actions.

Experience Influences Brain Mechanisms of Watching Dance

2011 ◽  
Vol 29 (supplement) ◽  
pp. 352-377 ◽  
Author(s):  
Seon Hee Jang ◽  
Frank E Pollick
Keyword(s):  
Motor Imagery ◽  
Visual Experience ◽  
Primary Motor Cortex ◽  
Action Observation ◽  
Brain Area ◽  
Retrosplenial Cortex ◽  
Imagery Task ◽  
Temporoparietal Junction ◽  
Action Observation Network ◽  
Viewing Experience

The study of dance has been helpful to advance our understanding of how human brain networks of action observation are influenced by experience. However previous studies have not examined the effect of extensive visual experience alone: for example, an art critic or dance fan who has a rich experience of watching dance but negligible experience performing dance. To explore the effect of pure visual experience we performed a single experiment using functional Magnetic Resonance Imaging (fMRI) to compare the neural processing of dance actions in 3 groups: a) 14 ballet dancers, b) 10 experienced viewers, c) 12 novices without any extensive dance or viewing experience. Each of the 36 participants viewed short 2-second displays of ballet derived from motion capture of a professional ballerina. These displays represented the ballerina as only points of light at the major joints. We wished to study the action observation network broadly and thus included two different types of display and two different tasks for participants to perform. The two different displays were: a) brief movies of a ballet action and b) frames from the ballet movies with the points of lights connected by lines to show a ballet posture. The two different tasks were: a) passively observe the display and b) imagine performing the action depicted in the display. The two levels of display and task were combined factorially to produce four experimental conditions (observe movie, observe posture, motor imagery of movie, motor imagery of posture). The set of stimuli used in the experiment are available for download after this paper. A random effects ANOVA was performed on brain activity and an effect of experience was obtained in seven different brain areas including: right Temporoparietal Junction (TPJ), left Retrosplenial Cortex (RSC), right Primary Somatosensory Cortex (S1), bilateral Primary Motor Cortex (M1), right Orbitofrontal Cortex (OFC), right Temporal Pole (TP). The patterns of activation were plotted in each of these areas (TPJ, RSC, S1, M1, OFC, TP) to investigate more closely how the effect of experience changed across these areas. For this analysis, novices were treated as baseline and the relative effect of experience examined in the dancer and experienced viewer groups. Interpretation of these results suggests that both visual and motor experience appear equivalent in producing more extensive early processing of dance actions in early stages of representation (TPJ and RSC) and we hypothesise that this could be due to the involvement of autobiographical memory processes. The pattern of results found for dancers in S1 and M1 suggest that their perception of dance actions are enhanced by embodied processes. For example, the S1 results are consistent with claims that this brain area shows mirror properties. The pattern of results found for the experienced viewers in OFC and TP suggests that their perception of dance actions are enhanced by cognitive processes. For example, involving aspects of social cognition and hedonic processing – the experienced viewers find the motor imagery task more pleasant and have richer connections of dance to social memory. While aspects of our interpretation are speculative the core results clearly show common and distinct aspects of how viewing experience and physical experience shape brain responses to watching dance.

scholarly journals Muscle-specific modulation of indirect inputs to primary motor cortex during action observation

2020 ◽  
Vol 238 (7-8) ◽  
pp. 1735-1744 ◽  
Author(s):  
Andreea Loredana Cretu ◽  
Kathy L. Ruddy ◽  
Alain Post ◽  
Nicole Wenderoth
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Action Observation

scholarly journals Noise-Correlation Is Modulated by Reward Expectation in the Primary Motor Cortex Bilaterally During Manual and Observational Tasks in Primates

2020 ◽  
Vol 14 ◽  
Author(s):  
Brittany Moore ◽  
Sheng Khang ◽  
Joseph Thachil Francis
Keyword(s):  
Motor Cortex ◽  
Firing Rate ◽  
Primary Motor Cortex ◽  
Action Observation ◽  
Noise Correlation ◽  
Information Channel ◽  
Qualitative Response ◽  
Computer Interfaces ◽  
Single Target ◽  
Target Center

Reward modulation is represented in the motor cortex (M1) and could be used to implement more accurate decoding models to improve brain-computer interfaces (BCIs; Zhao et al., 2018). Analyzing trial-to-trial noise-correlations between neural units in the presence of rewarding (R) and non-rewarding (NR) stimuli adds to our understanding of cortical network dynamics. We utilized Pearson’s correlation coefficient to measure shared variability between simultaneously recorded units (32–112) and found significantly higher noise-correlation and positive correlation between the populations’ signal- and noise-correlation during NR trials as compared to R trials. This pattern is evident in data from two non-human primates (NHPs) during single-target center out reaching tasks, both manual and action observation versions. We conducted a mean matched noise-correlation analysis to decouple known interactions between event-triggered firing rate changes and neural correlations. Isolated reward discriminatory units demonstrated stronger correlational changes than units unresponsive to reward firing rate modulation, however, the qualitative response was similar, indicating correlational changes within the network as a whole can serve as another information channel to be exploited by BCIs that track the underlying cortical state, such as reward expectation, or attentional modulation. Reward expectation and attention in return can be utilized with reinforcement learning (RL) towards autonomous BCI updating.

scholarly journals Effect of transcranial direct current stimulation in the first weeks after stroke: a preliminary study

2021 ◽  
Author(s):  
Marcela Tengler Carvalho Takahashi ◽  
Paulo Rodrigo Bázan ◽  
Joana Bisol Balardin ◽  
Danielle de Sá Boasquevisque ◽  
Edson Amaro Júnior ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Motor Performance ◽  
Sham Group ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Group Differences ◽  
Direct Current Stimulation ◽  
Cathodal Tdcs

Background: There is limited information about effects of transcranial Direct Current Stimulation(tDCS), delivered within the first weeks post-stroke, on performance of the paretic upper limb and on connectivity between motor areas in the affected and unaffected hemispheres. Objectives: We compared changes in Fugl-Meyer Assessment of Motor Recovery(FMA) scores, connectivity between the primary motor cortex of the unaffected(M1UH) and the affected hemisphere(M1AH), as well as between M1UH and the premotor cortex of the unaffected hemisphere(PMUH) before and after 6 sessions of cathodal tDCS targeting the primary motor cortex of the unaffected hemisphere(M1UH) early after stroke in 13 patients. Methods: This hypothesis-generating substudy was a randomized parallel, two-arm, double-blind, sham-controlled clinical trial performed at the Albert Einstein Hospital. Subjects were randomized active(N=6) or sham(N=7) groups. Results: Clinically relevant differences in FMA scores(≥ 9 points) were observed more often in the sham than in the active group. Between-group differences in changes in FMA scores were not statistically significant(Mann-Whitney test, p=0.133) but the effect size was -0.619(rank biserial correlation). Connectivity measures(Fisher’s z- transform of ROI-to-ROI correlations) between M1AH-M1UH increased in 5/6 participants in the active, and in 2/7 in the sham group after treatment. Between-group differences in changes in connectivity(M1UH-M1AH or PMUH-M1AH) were not statistically significant. In contrast with M1AH-M1UH connectivity, improvements in motor performance were more frequent in the active than in the sham group. Conclusions: Effects of cathodal tDCS on motor performance and on Resting-state Functional Magnetic Resonance Imaging may have distinct underpinnings in subjects at an early stage after stroke.

P20.11 Cathodal tDCS has a long-lasting inhibitory effect on primary motor cortex excitability

2011 ◽  
Vol 122 ◽  
pp. S149
Author(s):  
P. Profice ◽  
F. Ranieri ◽  
A. Uncini ◽  
L. Santoro ◽  
F. Notturno ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Inhibitory Effect ◽  
Cathodal Tdcs ◽  
Motor Cortex Excitability
Sign in / Sign up

Export Citation Format

Share Document