RESUMEN
Detecting errors in your own and others' actions is associated with discrepancies between intended and expected outcomes. The processing of salient events is associated with dopamine release, the balance of which is altered in Parkinson's disease (PD). Errors in observed actions trigger various electrocortical indices (e.g. mid-frontal theta, error-related delta, and error positivity [oPe]). However, the impact of dopamine depletion to observed errors in the same individual remains unclear. Healthy controls (HCs) and PD patients observed ecological reach-to-grasp-a-glass actions performed by a virtual arm from a first-person perspective. PD patients were tested under their dopaminergic medication (on-condition) and after dopaminergic withdrawal (off-condition). Analyses of oPe, delta, and theta-power increases indicate that while the formers were elicited after incorrect vs. correct actions in all groups, the latter were observed in on-condition but altered in off-condition PD. Therefore, different EEG error signatures may index the activity of distinct mechanisms, and error-related theta power is selectively modulated by dopamine depletion. Our findings may facilitate discovering dopamine-related biomarkers for error-monitoring dysfunctions that may have crucial theoretical and clinical implications.
RESUMEN
The ability to anticipate and detect changes in human movement helps people to modify their behaviors in ever changing environments. Studies indicate that expertise modulates observation of domain-specific actions in sports-a process that is crucial for adapting rapidly to a new situation, often before awareness of environmental changes is achieved. Here, we explored the electrophysiological underpinnings of wheelchair basketball players predicting the fate of free throws performed by wheelchair basketball athletes. We performed electroencephalography (EEG) in semi-professional wheelchair players with different degrees of expertise (players) and in ambulant, non-expert people (controls) while they observed movie stimuli of a free throw that could land inside or outside the basket. On each trial, participants were asked to predict the outcome of the throw. For each group, event-related potentials (ERPs) were averaged as a function of condition, using only the trials that were correctly predicted. Results show that compared to controls, expert players exhibit a greater negative amplitude of oCNV over Pz (an observational contingent negative variation-like waveform which is considered a marker of action effect prediction) during the wrist movement preceding the ball release (the last 100 ms of the shot), which carries the most crucial kinematic information regarding the fate of the throw. Our data provide further support to the view that functional modulation of the action observation network is associated with expertise.