Figure 1.
The stimuli (target and flankers) in each type of trial in the incongruent and congruent direction conditions are shown along with cartoons of the corresponding fingers involved. Target (correct) responses (green) with one (1T) or two (2T) fingers were indicated by a single arrowhead or double arrowhead target stimulus, respectively. Similarly, incorrect (flanker) responses (red) with one (1F) or two (2F) fingers were induced by single arrowhead or double arrowhead flanker stimuli, respectively. Yellow indicates fingers that were involved in both the error and correct responses, and thus did not have independent representation. White indicates fingers that were not involved in either response option.
Table 1.
Behavioral Data.
Figure 2.
Error frequency in the incongruent direction condition at each level of response representation: one-finger response represented in the target (1T) and two-finger responses represented in the target (2T), as well as one-finger response represented in the flanker (1F) and two-finger response represented in the flanker (2F).
Error frequency increased when the representation of the responses in the target and flanker were of the same size (1F/1T and 2F/2T) compared to when the representation of these responses was different (1F/2T and 2F/1T). The figure only includes errors where the erring response matched the response represented by the flanker stimulus. Error bars represent 1 SD.
Figure 3.
Box plot of the frequency of uninstructed corrective responses in the incongruent direction condition.
Corrections were more frequent following errors in 1F trials, independent of the representation of the correct response. Whiskers represent the range, the solid black bar represents the median, ***P<.001, Wilcoxon signed rank post-hoc tests corrected for multiple comparisons.
Figure 4.
The amplitude of the error-related negativity (ERN) was increased when two fingers were represented in the flanker, whereas the representation of the response in the target had no effect on the amplitude of the ERN.
Response alternatives were defined by the number of fingers represented in the target and flanker: one-finger flanker (1F) and one-finger target (1T), or two-finger flanker (2F) and two-finger target (2T). (A) Grand-average raw error waveforms from −150 to 350 ms locked to the response at the FCz ROI in the incongruent direction condition. (B) Scalp topographies of the grand-average raw waveforms in each condition at 40 ms after the response. (C) Grand-average error-correct difference waveforms locked to the response at the FCz ROI in the incongruent direction condition. (D) Scalp topographies of the grand-average difference waveforms in each condition at 40 ms after the response. Highlighted timeframe on grand-averaged waveforms represents the window used for detecting the peak amplitude of the ERN.
Figure 5.
The amplitude of the anterior N2 was higher in the incongruent direction condition when two fingers were represented in the flanker.
Response alternatives were defined by the number of fingers represented in the target and flanker: one-finger flanker (1F) and one-finger target (1T), or two-finger flanker (2F) and two-finger target (2T). (A) Grand-average waveforms from −300 to 300 ms locked to the response at the FCz ROI in the incongruent direction condition. (B) Grand-average waveforms from −300 to 300 ms locked to the response at the FCz ROI in the congruent condition. (C) Scalp topographies of the grand-average waveforms in the incongruent direction condition at 84 ms before the response. (D) Scalp topographies of the grand-average waveforms in the congruent condition at 100 ms before the response. Highlighted timeframe on grand-averaged waveforms represents the window used for detecting the peak amplitude of the anterior N2.
Figure 6.
The correct response-related negativity (CRN) and error-related positivity (Pe) did not respond to the manipulation of the representation of response alternatives.
Response alternatives were defined by the number of fingers represented in the target and flanker: one-finger flanker (1F) and one-finger target (1T), or two-finger flanker (2F) and two-finger target (2T). (A) Grand-average raw correct waveforms from −150 to 350 ms locked to the response in the incongruent condition at the FCz ROI. (B) The raw error waveforms from −150 to 800 ms locked to the response in the incongruent condition at the Pz ROI. (C) Grand-average error-correct difference waveforms from −150 to 800 ms locked to the response in the incongruent condition at the Pz ROI. Highlighted timeframe on grand-averaged waveforms represents the window used for detecting the peak amplitude of the CRN, and the mean voltage of the Pe.
Figure 7.
Source analysis of the error-related negativity (ERN) and anterior N2 revealed that source activity was highest in the dorsal anterior cingulate cortex (dACC) for both EEG components.
(A) The regions of interest (ROIs) chosen for the parcellation of the cingulate cortex are shown in the sagittal plane in the right and left hemispheres. The rostral anterior cingulate cortex (rACC) is shown in red, the dACC in blue and the posterior cingulate cortex (PCC) in green. (B) Source activity of the ERN at 40 ms after the response represented at each dipole mapped to the cortical mantle in the sagittal plane. The color bar represents the z-score value of the source activity as measured from a baseline from −150 to −50 ms before the response. Source activity is shown for the incongruent direction condition for each pair of response alternatives: one-finger error (1F) and one-finger correct (1T), and two-finger error (2F) and two-finger correct (2T). (C) Source activity of the anterior N2 at 84 ms before the response in the incongruent direction condition. The color bar represents the z-score value of the source activity as measured from a baseline from −250 to −150 ms before the response. (D) Average z-scored source activity of the ERN at each ROI from −10 to 90 ms around the time of the response, collapsed across response alternative conditions. (E) Average z-scored source activity of the anterior N2 at each ROI from −150 to −50 ms around the time of the response, collapsed across response alternative conditions. *P<.05, Tukey’s HSD tests.