TPJ-M1 interaction in the control of shared representations: New insights from tDCS and TMS combined.
There is extensive evidence that perceived and internally planned actions have a common representational basis: action observation can induce an automatic tendency to imitate others. If perceived and executed action, however, are based on shared representations, the question arises how we can distinguish self-related and other-related representations. It has been suggested that the control of shared representations involves a neural network centered on the temporo-parietal junction (TPJ). However, the specific role of the TPJ in controlling shared representations is still not clear. In a conflict situation where participants have to execute action A while observing action B, the TPJ might either facilitate the relevant action A or inhibit the irrelevant action B (mirror response). In the present study, we used transcranial Direct Current Stimulation (tDCS) to condition neural activity in the right temporo-parietal junction (TPJ). We then analyzed the corticospinal output as indexed by motor-evoked potentials (MEPs) induced by single-pulse TMS (spTMS) of the left primary motor cortex (M1) during action observation in the context of a conflict task. Results showed that tDCS-mediated increased control did not entail the attenuation of the task-irrelevant response activation: the effect of motor mirroring was not suppressed or reduced. Rather, facilitating TPJ activity via anodal tDCS selectively enhanced the instructed motor plan (self-related representation). This outcome supports the idea that TPJ plays a critical role in detecting the mismatch between self-related and other-related representations and is at work to enhance task-relevant representations.
Department of Experimental Psychology, University of Gent, 9000 Gent, Belgium. Electronic address: lara.bardi@ugent.be.
Lara
L
Bardi
Department of Experimental Clinical and Health Psychology, University of Gent, 9000 Gent, Belgium.
Davide
D
Gheza
Department of Experimental Psychology, University of Gent, 9000 Gent, Belgium.
Marcel
M
Brass
D000328:Adult; D019054:Evoked Potentials, Motor; D006801:Humans; D007100:Imitative Behavior; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology*; D011597:Psychomotor Performance; D013702:Temporal Lobe / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation; D050781:Transcranial Magnetic Stimulation; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult
Control of imitation; Motor evoked potentials; Shared representations; Temporo parietal junction; Transcranial direct current stimulation; Transcranial magnetic stimulation