title: Behavioral and brain pattern differences between acting and observing in an auditory task.
abstract: BACKGROUND
  Recent research has shown that errors seem to influence the patterns of brain activity. Additionally current notions support the idea that similar brain mechanisms are activated during acting and observing. The aim of the present study was to examine the patterns of brain activity of actors and observers elicited upon receiving feedback information of the actor's response.
  
  
  METHODS
  The task used in the present research was an auditory identification task that included both acting and observing settings, ensuring concurrent ERP measurements of both participants. The performance of the participants was investigated in conditions of varying complexity. ERP data were analyzed with regards to the conditions of acting and observing in conjunction to correct and erroneous responses.
  
  
  RESULTS
  The obtained results showed that the complexity induced by cue dissimilarity between trials was a demodulating factor leading to poorer performance. The electrophysiological results suggest that feedback information results in different intensities of the ERP patterns of observers and actors depending on whether the actor had made an error or not. The LORETA source localization method yielded significantly larger electrical activity in the supplementary motor area (Brodmann area 6), the posterior cingulate gyrus (Brodmann area 31/23) and the parietal lobe (Precuneus/Brodmann area 7/5).
  
  
  CONCLUSIONS
  These findings suggest that feedback information has a different effect on the intensities of the ERP patterns of actors and observers depending on whether the actor committed an error. Certain neural systems, including medial frontal area, posterior cingulate gyrus and precuneus may mediate these modulating effects. Further research is needed to elucidate in more detail the neuroanatomical and neuropsychological substrates of these systems.
authors.affiliation: Institute of Communications and Computer Systems, National Technical University of Athens, 9, Iroon Polytechneiou str,, 157 73 Zografou Campus, Athens, Greece. ikaran@esd.ece.ntua.gr.
authors.forename: Irene S
authors.initials: IS
authors.lastname: Karanasiou
authors.forename: Charalabos
authors.initials: C
authors.lastname: Papageorgiou
authors.forename: Eleni I
authors.initials: EI
authors.lastname: Tsianaka
authors.forename: George K
authors.initials: GK
authors.lastname: Matsopoulos
authors.forename: Errikos M
authors.initials: EM
authors.lastname: Ventouras
authors.forename: Nikolaos K
authors.initials: NK
authors.lastname: Uzunoglu