Boosting and Decreasing Action Prediction Abilities Through Excitatory and Inhibitory tDCS of Inferior Frontal Cortex.
Influential theories suggest that humans predict others' upcoming actions by using their own motor system as an internal forward model. However, evidence that the motor system is causally essential for predicting others' actions is meager. Using transcranial direct current stimulation (tDCS), we tested the role of the inferior frontal cortex (IFC), in action prediction (AP). We devised a novel AP task where participants observed the initial phases of right-hand reaching-to-grasp actions and had to predict their outcome (i.e., the goal/object to be grasped). We found that suppression by cathodal (inhibitory) tDCS of the left IFC, but not the left superior temporal sulcus or the right IFC, selectively impaired performance on the AP task, but not on a difficulty-matched control task. Remarkably, anodal (excitatory) tDCS of the left IFC brought about a selective improvement in the AP task. These findings indicate that the left IFC is necessary for predicting the outcomes of observed human right-hand actions. Crucially, our study shows for the first time that down- and up-regulating excitability within the motor system can hinder and enhance AP abilities, respectively. These findings support predictive coding theories of action perception and have implications for enhancement of AP abilities.
Department of Psychology and Center for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena Campus, 47521 Cesena, Italy.|IRCCS Santa Lucia Foundation, 00179 Rome, Italy.
Alessio
A
Avenanti
Department of Psychology and Center for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena Campus, 47521 Cesena, Italy.
Riccardo
R
Paracampo
Department of Psychology and Center for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena Campus, 47521 Cesena, Italy.
Laura
L
Annella
IRCCS Santa Lucia Foundation, 00179 Rome, Italy.|Department of Psychology, "Sapienza" University of Rome, 00185 Rome, Italy.
Emmanuele
E
Tidoni
IRCCS Santa Lucia Foundation, 00179 Rome, Italy.|Department of Psychology, "Sapienza" University of Rome, 00185 Rome, Italy.
Salvatore Maria
SM
Aglioti
D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult