Amplified engagement of prefrontal cortex during control of voluntary action in Tourette syndrome.

Tourette syndrome is characterized by 'unvoluntary' tics, which are compulsive, yet often temporarily suppressible. The inferior frontal gyrus is implicated in motor control, including inhibition of pre-potent actions through influences on downstream subcortical and motor regions. Although tic suppression in Tourette syndrome also engages the inferior frontal gyrus, it is unclear whether such prefrontal control of action is also dysfunctional: Tic suppression studies do not permit comparison with control groups, and neuroimaging studies of motor inhibition can be confounded by the concurrent expression or suppression of tics.

Effect of alcohol on the sense of agency in healthy humans.

Even at low to moderate doses, ingestion of the widely used recreational drug alcohol (ethanol) can impact cognitive and emotional processing. Recent studies show that the sense of agency (SoA; ie, the subjective experience of voluntary control over actions) can be modulated by specific pharmacological manipulations. The SoA, as quantified by the intentional binding (IB) paradigm, is enhanced by direct or indirect dopaminergic agonists in patients with Parkinson's disease and by ketamine (an N-methyl-D-aspartate (NMDA) receptor antagonist) in healthy individuals.

Face perception enhances insula and motor network reactivity in Tourette syndrome.

Tourette syndrome is a neurodevelopmental disorder, characterized by motor and phonic tics. Tics are typically experienced as avolitional, compulsive, and associated with premonitory urges. They are exacerbated by stress and can be triggered by external stimuli, including social cues like the actions and facial expressions of others.

Don't make me angry, you wouldn't like me when I'm angry: Volitional choices to act or inhibit are modulated by subliminal perception of emotional faces.

Volitional action and self-control-feelings of acting according to one's own intentions and in being control of one's own actions-are fundamental aspects of human conscious experience. However, it is unknown whether high-level cognitive control mechanisms are affected by socially salient but nonconscious emotional cues. In this study, we manipulated free choice decisions to act or withhold an action by subliminally presenting emotional faces: In a novel version of the Go/NoGo paradigm, participants made speeded button-press responses to Go targets, withheld responses to NoGo targets, and made spontaneous, free choices to execute or withhold the response for Choice targets.

Illusory Temporal Binding in Meditators.

We investigate conditions in which more accurate metacognition may lead to greater susceptibility to illusion and thus conditions under which mindfulness meditation may lead to less accurate perceptions. Specifically, greater awareness of intentions may lead to an illusory compression of time between a voluntary action and its outcome ("intentional binding"). Here, we report that experienced Buddhist mindfulness meditators rather than non-meditators display a greater illusory shift of the timing of an outcome toward an intentional action.

Choosing to Stop: Responses Evoked by Externally Triggered and Internally Generated Inhibition Identify a Neural Mechanism of Will.

Inhibiting inappropriate action is key to human behavioral control. Studies of action inhibition largely investigated external stop signals, yet these are rare in everyday life. Instead healthy adults exert "self-control," implying an ability to decide internally to stop actions.

Subliminal priming of intentional inhibition.

Intentional choice is an important process underlying human behaviour. Intentional inhibition refers to the capacity to endogenously cancel an about-to-be-executed action at the last moment. Previous research suggested that such intentional inhibitory control requires conscious effort and awareness.

Hedonic value of intentional action provides reinforcement for voluntary generation but not voluntary inhibition of action.

Intentional inhibition refers to stopping oneself from performing an action at the last moment, a vital component of self-control. It has been suggested that intentional inhibition is associated with negative hedonic value, perhaps due to the frustration of cancelling an intended action. Here we investigate hedonic implications of the free choice to act or inhibit.

Action simulation: time course and representational mechanisms.

The notion of action simulation refers to the ability to re-enact foreign actions (i.e., actions observed in other individuals).

The perception of prototypical motion: synchronization is enhanced with quantitatively morphed gestures of musical conductors.

Aesthetic theories have long suggested perceptual advantages for prototypical exemplars of a given class of objects or events. Empirical evidence confirmed that morphed (quantitatively averaged) human faces, musical interpretations, and human voices are preferred over most individual ones. In this study, biological human motion was morphed and tested for prototype effects in task-specific actions, perceptual judgments, and kinematic characteristics.

Movement kinematics affect action prediction: comparing human to non-human point-light actions.

The influence of movement kinematics on the accuracy of predicting the time course of another individual's actions was studied. A human point-light shape was animated with human movement (natural condition) and with artificial movement that was more uniform regarding velocity profiles and trajectories (artificial condition). During brief occlusions, the participants predicted the actions in order to judge after occlusion whether the actions were continued coherently in time or shifted to an earlier or later frame.

Before, during and after you disappear: aspects of timing and dynamic updating of the real-time action simulation of human motions.

The detailed dynamics of action simulation was investigated using the occluder paradigm: a point light actor (PLA) was shown, then briefly occluded from view, during which period action simulation was generated. Following occlusion, the PLA reappeared, either a progression of the motion as it should be post-occlusion or temporally shifted earlier/later. Participants made judgements on whether the reappearing PLA was too early or too late to be a correct continuation (Experiments 1 and 3) or whether it was a veridical continuation or not (Experiment 2).

The influence of visual training on predicting complex action sequences.

Linking observed and executable actions appears to be achieved by an action observation network (AON), comprising parietal, premotor, and occipitotemporal cortical regions of the human brain. AON engagement during action observation is thought to aid in effortless, efficient prediction of ongoing movements to support action understanding. Here, we investigate how the AON responds when observing and predicting actions we cannot readily reproduce before and after visual training.

Robotic movement preferentially engages the action observation network.

As humans, we gather a wide range of information about other people from watching them move. A network of parietal, premotor, and occipitotemporal regions within the human brain, termed the action observation network (AON), has been implicated in understanding others' actions by means of an automatic matching process that links observed and performed actions. Current views of the AON assume a matching process biased towards familiar actions; specifically, those performed by conspecifics and present in the observer's motor repertoire.

Can you see me in the snow? Action simulation aids the detection of visually degraded human motion.

Using a novel paradigm, we demonstrate that action simulation can directly facilitate ongoing perception of people's movements. Point-light actors (PLAs) representing common human motions were shown embedded in a visual noise reminiscent of "TV snow". At first, the PLAs were perceived clearly, then occluded from view for a short duration, during which it was hypothesized that a real-time action simulation was generated tracking the motion's course.

Line by line: the ERP correlates of stroke order priming in letters.

The perception of written letters reflects the action sequences that produce them. Faster recognition is observed for letters presented as sequences of strokes in a temporal order consistent with letter writing, compared to an inconsistent order. During a speeded letter identification task, parietal event-related potential (ERP) components were analysed separately for each stroke-frame in action-consistent and inconsistent stimulus sequences, during both passive and active (task-engaged) viewing.

Temporal order of strokes primes letter recognition.

Does the perception of objects that are the result of human actions reflect the underlying temporal structure of the actions that gave rise to them? We tested whether the temporal order of letter strokes influences letter recognition. In three experiments, participants were asked to identify letters that temporally unfolded as an additive sequence of letter strokes, either consistent or inconsistent with common writing action. Participants were significantly faster to identify letters from consistent temporal sequences, indicating that the initial part of the sequence contained sufficient information to prime letter recognition.