Prefrontal-cingulate activation during executive control: which comes first?
The Stroop test requires executive control functions, in particular inhibition of a learned routine (in this case, word reading). The spatiotemporal analysis of brain activation during Stroop task execution was performed in 16 healthy subjects using high-density event-related potentials (ERPs) and dipole source modeling (BESA software). Scalp ERP analysis revealed the neurophysiological substrate of the interference effect: first, a greater negativity in the incongruent as compared to the congruent and neutral conditions was found between 350 and 450 ms poststimulus over left frontocentral scalp regions. Source analysis of the difference wave (incongruent-congruent) indicated that a generator localized in left prefrontal cortex (PFC) contributed to this effect. Second, immediately after the first effect, a greater positivity in the incongruent as compared to the congruent and neutral conditions developed between 450 and 550 ms poststimulus over midline frontocentral scalp regions. A generator of this effect was located in right anterior cingulate cortex (ACC). ACC activation seems to follow the activation of PFC with some overlap between the two components. Possible interpretation of this finding is that PFC signals ACC when executive control is required and ACC implements the control.
Markela-Lerenc
Jaana
J
Department of Psychiatry, University of Heidelberg, Voss-Strasse 4, 69115, Heidelberg, Germany. jaana_makela@med.uni-heidelberg.de
Ille
Nicole
N
Kaiser
Stefan
S
Fiedler
Peter
P
Mundt
Christoph
C
Weisbrod
Matthias
M
D000328:Adult; D000704:Analysis of Variance; D004569:Electroencephalography / Q000379:methods; D005071:Evoked Potentials / Q000502:physiology*; D006179:Gyrus Cinguli / Q000502:physiology*; D006801:Humans; D010775:Photic Stimulation / Q000379:methods; D017397:Prefrontal Cortex / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*