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ABSTRACT: Different views on the origin of deficits in action chaining in autism spectrum disorders (ASD) have been posited, ranging from functional impairments in action planning to internal models supporting motor control. Thirty-one children and adolescents with ASD and twenty-nine matched controls participated in a two-choice reach-to-grasp paradigm wherein participants received cueing information indicating either the object location or the required manner of grasping. A similar advantage for location cueing over grip cueing was found in both groups. Both accuracy and reaction times of the ASD group were indistinguishable from the control group. In contrast, movement times of the ASD group were significantly delayed in comparison with controls. These findings suggest that movement execution rather than action planning is deficient in ASD, and that deficits in action chaining derive from impairments in internal action models supporting action execution.
Journal of Autism and Childhood Schizophrenia 04/2013; · 3.06 Impact Factor
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ABSTRACT: Paying attention to thin media models may negatively affect women's self-evaluation. This study aimed to reduce the amount of attention that young women give to appearance-related information by challenging the sociocultural norms for appearance, and studied the moderating role of self-esteem. Seventy-one college women either received norm-confirming, norm-challenging, or no information regarding the sociocultural norms for appearance. Subsequently, participants' visual attention to appearance-related and neutral advertisements was measured using an eye-tracker. The results demonstrate that when no information or norm-confirming information was received, women with lower self-esteem paid more attention to the appearance-related advertisements than women with higher self-esteem. Importantly however, when norm-challenging information was received, women with lower self-esteem paid significantly less attention to the appearance-related ads than women with lower self-esteem who did not receive this manipulation. These findings indicate that challenging the sociocultural norms for appearance can attenuate the amount of attention women give to appearance-related media.
Body image 03/2013; · 2.19 Impact Factor
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ABSTRACT: The present study investigated the effect of sexually objectifying music video exposure on young women's implicit bodily self-perception and the moderating role of self-esteem. Fifty-six college women of normal weight were either exposed to three sexually objectifying music videos or three neutral music videos. Perceived and ideal body size were measured both before and after video exposure, using horizontally stretched and compressed photographs of the participant's own body in swimming garment. As expected, only women low (but not high) in self-esteem were negatively affected by the sexually objectifying content of the music videos: they perceived themselves as bigger and showed an increased discrepancy between their perceived and ideal body size after video exposure. The neutral music videos did not influence women's bodily self-perceptions. These findings suggest that body image is a flexible construct, and that high self-esteem can protect women against the adverse effects of sexually objectifying media.
Body image 09/2012; · 2.19 Impact Factor
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ABSTRACT: Detecting errors in other's actions is of pivotal importance for joint action, competitive behavior and observational learning. Although many studies have focused on the neural mechanisms involved in detecting low-level errors, relatively little is known about error-detection in everyday situations. The present study aimed to identify the functional and neural mechanisms whereby we understand the correctness of other's actions involving well-known objects (e.g. pouring coffee in a cup). Participants observed action sequences in which the correctness of the object grasped and the grip applied to a pair of objects were independently manipulated. Observation of object violations (e.g. grasping the empty cup instead of the coffee pot) resulted in a stronger P3-effect than observation of grip errors (e.g. grasping the coffee pot at the upper part instead of the handle), likely reflecting a reorienting response, directing attention to the relevant location. Following the P3-effect, a parietal slow wave positivity was observed that persisted for grip-errors, likely reflecting the detection of an incorrect hand-object interaction. These findings provide new insight in the functional significance of the neurophysiological markers associated with the observation of incorrect actions and suggest that the P3-effect and the subsequent parietal slow wave positivity may reflect the detection of errors at different levels in the action hierarchy. Thereby this study elucidates the cognitive processes that support the detection of action violations in the selection of objects and grips.
PLoS ONE 01/2012; 7(5):e36450. · 4.09 Impact Factor
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ABSTRACT: Millions of people worldwide engage in online role-playing with their avatar, a virtual agent that represents the self. Previous behavioral studies have indicated that many gamers identify more strongly with their avatar than with their biological self. Through their avatar, gamers develop social networks and learn new social-cognitive skills. The cognitive neurosciences have yet to identify the neural processes that underlie self-identification with these virtual agents. We applied functional neuroimaging to 22 long-term online gamers and 21 nongaming controls, while they rated personality traits of self, avatar, and familiar others. Strikingly, neuroimaging data revealed greater avatar-referential cortical activity in the left inferior parietal lobe, a region associated with self-identification from a third-person perspective. The magnitude of this brain activity correlated positively with the propensity to incorporate external body enhancements into one's bodily identity. Avatar-referencing furthermore recruited greater activity in the rostral anterior cingulate gyrus, suggesting relatively greater emotional self-involvement with one's avatar. Post-scanning behavioral data revealed superior recognition memory for avatar relative to others. Interestingly, memory for avatar positively covaried with play duration. These findings significantly advance our knowledge about the brain's plasticity to self-identify with virtual agents and the human cognitive-affective potential to live and learn in virtual worlds.
Cerebral Cortex 09/2011; 22(7):1577-85. · 6.54 Impact Factor
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ABSTRACT: In line with previous studies, showing that abstract concepts like "power" or "god" implicitly activate spatial associations, in the present study we hypothesized that spatial associations are coactivated during the processing of acronyms referring to names of political parties as well. In four studies, it was found that the reading of these acronyms was accompanied by the implicit activation of spatial left-right associations. That is, participants responded faster to left-wing parties by means of a left-hand button press and vice versa for right-wing parties (Experiments 1 to 3), and participants responded faster when a political acronym was presented at the side of the screen corresponding to the political orientation of the acronym (Experiment 4). Interestingly, a correlation was observed between the effect size for left-wing parties and participants' political preferences, suggesting that the reaction time effects reflect the perceived distance of a party to one's own political orientation. Together these findings indicate that spatial representations activated in response to political acronyms do not simply reflect lexical-semantic associations or spatial metaphors, but representations of parties' political orientation relative to one's own sociopolitical position.
Quarterly journal of experimental psychology (2006) 11/2010; 63(11):2202-19. · 1.96 Impact Factor
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ABSTRACT: Humans are faster to perform a given action following observation of that same action. Converging evidence suggests that the human mirror neuron system (MNS) plays an important role in this phenomenon. However, the specificity of the neural mechanisms governing this effect remain controversial. Specialist theories of imitation suggest that biological cues are maximally capable of eliciting imitative facilitation. Generalist models, on the other hand, posit a broader role for the MNS in linking visual stimuli with appropriate responses. In the present study, we investigated the validity of these two theoretical approaches by disrupting the left and right inferior frontal gyrus (IFG) during the preparation of congruent (imitative) and incongruent (complementary) actions cued by either biological (hand) or non-biological (static dot) stimuli. Delivery of TMS over IFG abolished imitative response facilitation. Critically, this effect was identical whether actions were cued by biological or non-biological stimuli. This finding argues against theories of imitation in which biological stimuli are treated preferentially and stresses the notion of the IFG as a vital center of general perception-action coupling in the human brain.
Frontiers in Behavioral Neuroscience 01/2010; 4:5.
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ABSTRACT: In the present EEG study we investigated whether semantic knowledge for object use is represented in motor-related brain areas. Subjects were required to perform actions with everyday objects and to maintain either a meaningful or a meaningless end posture with the object. Analysis of the EEG data focused on the beta-frequency band, as previous studies have indicated that the maintenance of a posture is reflected in stronger beta-oscillations. Time frequency analysis indicated that the execution of actions resulting in a meaningless compared to a meaningful end posture was accompanied by a stronger beta-desynchronization towards the end of the movement and a stronger subsequent beta-rebound after posture-onset. The effect in the beta-frequency band was localized to premotor, parietal and medial frontal areas and could not be attributed to differences in timing or movement complexity between meaningful and meaningless actions. Together these findings directly show that the motor system is differentially activated during the execution and maintenance of semantically correct or incorrect end postures. This suggests that semantic object knowledge is indeed represented in motor-related brain areas, organized around specific end postures associated with the use of objects.
Frontiers in Human Neuroscience 01/2010; 4:8. · 2.34 Impact Factor
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ABSTRACT: In the present event-related potential (ERP) study we investigated the neural and temporal dynamics of motor imagery in participants with right-sided hemiparetic cerebral palsy (HCP; n = 10) and in left-handed control participants (n = 10). A mental rotation task was used in which participants were required to judge the laterality of hand pictures. At a behavioral level participants with HCP were slower in making hand laterality judgments compared to control subjects, especially when presented with pictures representing the affected hand. At a neural level, individuals with HCP were characterized by a reduced rotation-related negativity (RRN) over parietal areas, that was delayed in onset with respect to control participants. Interestingly, participants that were relatively mildly impaired showed a stronger RRN for the rotation of right-hand stimuli than participants that were more strongly impaired in their motor function, suggesting a direct relation between the motor imagery process and the biomechanical constraints of the participant. Together, the results provide new insights in the relation between motor imagery and motor capabilities and indicate that participants with HCP may be characterized by a compromised ability to use motor imagery.
Frontiers in neurology. 01/2010; 1:150.
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ABSTRACT: Mankind is unique in her ability for observational learning, i.e. the transmission of acquired knowledge and behavioral repertoire through observation of others' actions. In the present study we used electrophysiological measures to investigate brain mechanisms of observational learning. Analysis investigated the possible functional coupling between occipital (alpha) and motor (mu) rhythms operating in the 10 Hz frequency range for translating "seeing" into "doing". Subjects observed movement sequences consisting of six consecutive left or right hand button presses directed at one of two target-buttons for subsequent imitation. Each movement sequence was presented four times, intervened by short pause intervals for sequence rehearsal. During a control task subjects observed the same movement sequences without a requirement for subsequent reproduction. Although both alpha and mu rhythms desynchronized during the imitation task relative to the control task, modulations in alpha and mu power were found to be largely independent from each other over time, arguing against a functional coupling of alpha and mu generators during observational learning. This independence was furthermore reflected in the absence of coherence between occipital and motor electrodes overlaying alpha and mu generators. Instead, coherence analysis revealed a pair of symmetric fronto-parietal networks, one over the left and one over the right hemisphere, reflecting stronger coherence during observation of movements than during pauses. Individual differences in fronto-parietal coherence were furthermore found to predict imitation accuracy. The properties of these networks, i.e. their fronto-parietal distribution, their ipsilateral organization and their sensitivity to the observation of movements, match closely with the known properties of the mirror neuron system (MNS) as studied in the macaque brain. These results indicate a functional dissociation between higher order areas for observational learning (i.e. parts of the MNS as reflected in 10 Hz coherence measures) and peripheral structures (i.e. lateral occipital gyrus for alpha; central sulcus for mu) that provide low-level support for observation and motor imagery of action sequences.
PLoS ONE 01/2010; 5(12):e14482. · 4.09 Impact Factor
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ABSTRACT: Over the past two decades single cell recordings in primates and neuroimaging experiments in humans have uncovered the key properties of visuo-motor mirror neurons located in monkey premotor cortex and parietal cortices as well as homologous areas in the human inferior frontal and inferior parietal cortices which presumably house neurons with similar response properties. One of the most interesting claims regarding the human mirror neuron system (MNS) is that its activity reflects high-level action understanding. If this was the case, one would expect signal in the MNS to differentiate between meaningful and meaningless actions. In the current experiment we tested this prediction using a novel paradigm. Functional magnetic resonance images were collected while participants viewed (i) short films of object-directed actions (ODAs) which were either semantically meaningful, i.e. a hand pressed a stapler or semantically meaningless, i.e. a foot pressed a stapler, (ii) short films of pantomimed actions and (iii) static pictures of objects. Consistent with the notion that the MNS represents high-level action understanding, meaningful and meaningless actions elicited BOLD signal differences at bilateral sites in the supramarginal gyrus (SMG) of the inferior parietal lobule (IPL) where we observed a double dissociation between BOLD response and meaningfullness of actions. Comparison of superadditive responses in the inferior frontal gyrus (IFG) and IPL (supramarginal) regions revealed differential contributions to action understanding. These data further specify the role of specific components of the MNS in understanding object-directed actions.
Brain research 12/2009; 1315:63-74. · 2.46 Impact Factor
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ABSTRACT: The present study assessed the functional organization of action semantics by asking subjects to categorize pictures of an actor holding objects with a correct or incorrect grip at either a correct or incorrect goal location. Overall, reaction times were slower if the object was presented with an inappropriate posture, and this effect was stronger for goal violations compared with grip violations (Experiment 1). In addition, the retrieval of action semantics was found accompanied by the implicit activation of motor representations. Body-related objects (e.g., cup) were classified faster when a movement toward the subject's body was required, whereas world-related objects (e.g., pincers) were responded to faster with a movement in the opposite direction (Experiments 2 and 3). In contrast, when subjects were required to retrieve only visual semantics (Experiment 4), no interference effects of postural information were observed, and motor representations were only partially activated. These findings suggest that action semantics can be accessed independently from visual semantics and that the retrieval of action semantics is supported by functional motor activation reflecting the prototypical use of an object.
Journal of Experimental Psychology Human Perception & Performance 09/2009; 35(4):1118-28. · 3.06 Impact Factor
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ABSTRACT: There are several models of premotor cortex contributions to sensorimotor behavior. For instance, the ventral premotor cortex (PMv) appears to be involved in processing visuospatial object properties for grasping, whereas the dorsal premotor cortex (PMd) is involved in using arbitrary rules to guide advance motor planning. These models have focused on individual movements. Here, we examine the premotor responses evoked during the processing of individual movements functionally embedded in an action. We tested whether processing hand-object interactions and action end states would differentially engage PMv and PMd. We used a repetition suppression (RS)-functional magnetic resonance imaging paradigm in which we independently manipulated the observed grip, the end position of the object (independent of its spatial location), and the hand trajectory. By comparing novel and repeated trials for each of these action components, we could isolate RS effects specific to each of them. Repeating the grasp component attenuated activity in right PMv, whereas repeating the end state of the action reduced blood oxygen level-dependent activity in the left PMd. These results suggest that PMv is involved in controlling the kinematic means of an appropriate hand-object interaction, whereas PMd is focused on specifying the desired end state of an action.
Cerebral Cortex 04/2009; 19(11):2736-45. · 6.54 Impact Factor
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ABSTRACT: Humans are experts in cooperating with each other when trying to accomplish tasks they cannot achieve alone. Recent studies of joint action have shown that when performing tasks together people strongly rely on the neurocognitive mechanisms that they also use when performing actions individually, that is, they predict the consequences of their co-actor’s behavior through internal action simulation. Context-sensitive action monitoring and action selection processes, however, are relatively underrated but crucial ingredients of joint action. In the present paper, we try to correct the somewhat simplified view on joint action by reviewing recent studies of joint action simulation, monitoring, and selection while emphasizing the intricate interrelationships between these processes. We complement our review by defining the contours of a neurologically plausible computational framework of joint action.
Topics in Cognitive Science 03/2009; 1(2):340 - 352. · 2.88 Impact Factor
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ABSTRACT: Event-Related Potentials (ERPs) provide non-invasive measurements of the electrical activity on the scalp related to the processing of stimuli and preparation of responses by the brain. In this paper an ERP-signal classification method is proposed for discriminating between ERPs of correct and incorrect responses of actors and of observers seeing an actor making such responses. The classification method targeted signals containing error-related negativity (ERN) and error positivity (Pe) components, which are typically associated with error processing in the human brain. Feature extraction consisted of Multivariate Autoregressive modeling combined with the Simulated Annealing technique. The resulting information was subsequently classified by means of an Artificial Neural Network (ANN) using back-propagation algorithm under the "leave-one-out cross-validation" scenario and the Fuzzy C-Means (FCM) algorithm. The ANN consisted of a multi-layer perceptron (MLP). The approach yielded classification rates of up to 85%, both for the actors' correct and incorrect responses and the corresponding ERPs of the observers. The electrodes needed for such classifications were situated mainly at central and frontal areas. Results provide indications that the classification of the ERN is achievable. Furthermore, the availability of the Pe signals, in addition to the ERN, improves the classification, and this is more pronounced for observers' signals. The proposed ERP-signal classification method provides a promising tool to study error detection and observational-learning mechanisms in performance monitoring and joint-action research, in both healthy and patient populations.
The Open Medical Informatics Journal 02/2009; 3:32-43.
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ABSTRACT: A robust finding in imitation literature is that people perform their actions more readily if they are congruent with the behavior of another person. These action congruency effects are typically explained by the idea that the observation of someone else acting automatically activates our motor system in a directly matching way. In the present study action congruency effects were investigated between an imitation task and a complementary action task. Subjects imitated or complemented a virtual actor's grasp on a manipulandum. In both tasks, a color-cue could be presented forcing subjects to ignore the task rule and execute a predefined grasp. Reaction times revealed a reversal of congruency effects in the complementary action task, suggesting that subjects were able to circumvent the automatic tendency to copy actions or postures of another person. In 2 additional control experiments, congruency effects were replicated, and a Simon effect was identified to underlie faster responses in the imitation task. These results make a case against current theoretical views on imitation and direct matching in favor of more flexible models of perception-action coupling.
Journal of Experimental Psychology Human Perception & Performance 01/2009; 34(6):1493-500. · 3.06 Impact Factor
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ABSTRACT: The ability to detect and process errors made by others plays an important role is many social contexts. The capacity to process errors is typically found to rely on sites in the medial frontal cortex. However, it remains to be determined whether responses at these sites are driven primarily by action errors themselves or by the affective consequences normally associated with their commission. Using an experimental paradigm that disentangles action errors and the valence of their affective consequences, we demonstrate that sites in the medial frontal cortex (MFC), including the ventral anterior cingulate cortex (vACC) and pre-supplementary motor area (pre-SMA), respond to action errors independent of the valence of their consequences. The strength of this response was negatively correlated with the empathic concern subscale of the Interpersonal Reactivity Index. We also demonstrate a main effect of self-identification by showing that errors committed by friends and foes elicited significantly different BOLD responses in a separate region of the middle anterior cingulate cortex (mACC). These results suggest that the way we look at others plays a critical role in determining patterns of brain activation during error observation. These findings may have important implications for general theories of error processing.
Social Cognitive and Affective Neuroscience 10/2008; 4(1):10-22. · 6.13 Impact Factor
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ABSTRACT: Recent research has demonstrated that cortical motor areas are engaged when observing motor actions of others. However, little is known about the possible contribution of the motor system for evaluating the correctness of others' actions. To address this question we designed an MEG experiment in which subjects were executing and observing motor actions with and without errors. In the execution task subjects were asked to make speeded button presses according to instruction cues. During the observation task, they viewed pictures of an actor's hand making button presses which were correct or incorrect according to the cues. Time-frequency representations of the MEG data demonstrated a depression in oscillatory activity in the beta band activity (15-35 Hz) during execution followed by a beta rebound that was stronger for incorrect compared to correct executions. During the observation task, a similar time-course of the beta activity was identified and importantly the modulations were stronger for the observation of incorrect than correct actions. Sources accounting for the difference in beta activity between correct and incorrect actions were localized using a beamforming technique. Both for the execution and observation conditions sources were identified to the dorsal motor areas comprising both primary and pre-motor cortex. Our findings demonstrate that not only is cortical motor activity modulated by action observation, but the modulation increases when the observed action is erroneous. This suggests that the motor system is engaged in evaluating the correctness of the actions of others.
NeuroImage 05/2008; 40(2):767-75. · 5.89 Impact Factor
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ABSTRACT: Lateralized magnetic fields were recorded from 12 subjects using a 151 channel magnetoencephalography (MEG) system to investigate temporal and functional properties of motor activation to the observation of goal-directed hand movements by a virtual actor. Observation of left and right hand movements generated a neuromagnetic lateralized readiness field (LRF) over contralateral motor cortex. The early onset of the LRF and the fact that the evoked component was insensitive to the correctness of the observed action suggest the operation of a fast and automatic form of motor resonance that may precede higher levels of action understanding.
Social neuroscience 02/2008; 3(3-4):213-28. · 3.17 Impact Factor
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ABSTRACT: To interact effectively with our environment, we need to specify the intended outcomes (goals) of our actions. In this process, immediate goals and final goals can be regarded as different levels within a hierarchically organized system for action planning: immediate goals and movement details are selected to accomplish more remote goals. Behavioral studies support this notion of different levels of action planning, but the neurophysiological basis remains unclear. Using fMRI, we examined the neural correlates of preparing object manipulations based on either the desired end-state (the final goal) or the initial movement towards a target (the immediate goal). Subjects had to insert an object (consisting of a large and a small cube) into one of two corresponding large and small slots. The subjects were cued on either which slot to fill (Final Goal trials) or which object part to grasp (Immediate Goal trials). These actions required similar movements, but different planning. During Final Goal trials, there was differential preparatory activity along the superior frontal gyrus (bilaterally) and in left inferior parietal cortex. Immediate Goal trials evoked differential activity in occipito-parietal and occipito-temporal cortex. These findings support the notion that actions can be planned at different levels. We show that different fronto-parietal circuits plan the same action, by a relative emphasis on either selecting a sequence of movements to achieve a desired end-state, or selecting movements spatially compatible with given object properties.
NeuroImage 09/2007; 37(2):589-98. · 5.89 Impact Factor
