title: "How Did I Make It?": Uncertainty about Own Motor Performance after Inhibition of the Premotor Cortex.
abstract: Optimal motor performance requires the monitoring of sensorimotor input to ensure that the motor output matches current intentions. The brain is thought to be equipped with a "comparator" system, which monitors and detects the congruence between intended and actual movement; results of such a comparison can reach awareness. This study explored in healthy participants whether the cathodal transcranial direct current stimulation (tDCS) of the right premotor cortex (PM) and right posterior parietal cortex (PPC) can disrupt performance monitoring in a skilled motor task. Before and after tDCS, participants underwent a two-digit sequence motor task; in post-tDCS session, single-pulse TMS (sTMS) was applied to the right motor cortex, contralateral to the performing hand, with the aim of interfering with motor execution. Then, participants rated on a five-item questionnaire their performance at the motor task. Cathodal tDCS of PM (but not sham or PPC tDCS) impaired the participants' ability to evaluate their motor performance reliably, making them unconfident about their judgments. Congruently with the worsened motor performance induced by sTMS, participants reported to have committed more errors after sham and PPC tDCS; such a correlation was not significant after PM tDCS. In line with current computational and neuropsychological models of motor control and awareness, the present results show that a mechanism in the PM monitors and compares intended versus actual movements, evaluating their congruence. Cathodal tDCS of the PM impairs the activity of such a "comparator," disrupting self-confidence about own motor performance.
authors.affiliation: University of Milano-Bicocca and NeuroMi-Milan Centre for Neuroscience.|IRCSS Istituto Auxologico Italiano, Milano, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Bolognini
authors.affiliation: University of Milano-Bicocca and NeuroMi-Milan Centre for Neuroscience.|IRCSS Istituto Auxologico Italiano, Milano, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Zigiotto
authors.affiliation: University of Milano-Bicocca and NeuroMi-Milan Centre for Neuroscience.
authors.forename: Maíra Izzadora Souza
authors.initials: MI
authors.lastname: Carneiro
authors.affiliation: University of Milano-Bicocca and NeuroMi-Milan Centre for Neuroscience.|IRCSS Istituto Auxologico Italiano, Milano, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Vallar
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001364:Awareness; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007600:Judgment / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D011930:Reaction Time; D012649:Self Concept; D011795:Surveys and Questionnaires; D065908:Transcranial Direct Current Stimulation; D035501:Uncertainty; D055815:Young Adult