title: Transcranial alternating current stimulation to the inferior parietal lobe decreases mu suppression to egocentric, but not allocentric hand movements.
abstract: Egocentric vs. allocentric perspective during observation of hand movements has been related to self-other differentiation such that movements observed from an egocentric viewpoint have been considered as self-related while movements observed from an allocentric viewpoint have been considered as belonging to someone else. Correlational studies have generally found that egocentric perspective induces greater neurophysiological responses and larger behavioral effects compared to an allocentric perspective. However, recent studies question previous findings by reporting greater (μ) suppression and greater transcranial magnetic stimulation (TMS)-induced motor-evoked potentials (MEPs) during observation of allocentric compared to egocentric movements. Furthermore, self-other differentiation has been generally related to activity within the inferior parietal lobe (IPL), but direct evidence for a causal and functional role of IPL in self-other differentiation is lacking. The current study was therefore designed to investigate the influence that IPL exerts on self-other differentiation. To this aim, we measured the impact of individually adjusted alpha-tuned transcranial alternating current stimulation (tACS) applied over IPL on μ-suppression during hands movement observation from an egocentric and allocentric perspective. Electroencephalography (EEG) was recorded during movement observation before and immediately after tACS. Results demonstrated that tACS decreased μ-reactivity over sensorimotor (but not visual) regions for egocentric (but not allocentric) movement observation providing direct evidence for a causal involvement of IPL in the observation of self- but not other-related hand movement.
authors.affiliation: Centre for Brain Science, Department of Psychology, University of Essex, CO4 3SQ, United Kingdom. Electronic address: mbernt@essex.ac.uk.
authors.forename: Monica B
authors.initials: MB
authors.lastname: Berntsen
authors.affiliation: Centre for Brain Science, Department of Psychology, University of Essex, CO4 3SQ, United Kingdom.
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Cooper
authors.affiliation: Centre for Brain Science, Department of Psychology, University of Essex, CO4 3SQ, United Kingdom.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Romei
mesh_terms: D000704:Analysis of Variance; D004569:Electroencephalography; D019054:Evoked Potentials, Motor; D005260:Female; D006225:Hand; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009778:Occipital Lobe / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology*; D010775:Photic Stimulation; D012649:Self Concept; D012938:Social Perception; D065908:Transcranial Direct Current Stimulation; D055815:Young Adult
keywords: EEG; IPL; perspectives; self-other differentiation; tACS