Fig 1.
Overview of the different ERP components and the oscillatory marker reported in the preparation, implementation and execution phases of saccadic eye movements in cue-locked, target-locked and saccade-locked epochs. PSP: presaccadic positivity; LPP: late parietal positivity; A: antisaccade; P: prosaccade.
Table 1.
Linguistic and environmental background measures as assessed by a questionnaire are reported in the table. The mean and standard deviation (SD) is indicated for each category.
Fig 2.
Timing of a prosaccade and an antisaccade trial.
Fig 3.
Effective connectivity model tested in a DCM analysis and equivalent current dipole locations.
A The neuronal sources in the model are connected with forward (black), backward (dark grey) or lateral (light grey) connections. Connections that are modelled to vary between experimental conditions are depicted with dotted lines. Connections between V1 and FEF as well as LIP and FEF also connect to the contralateral side but are depicted only for the ipsilateral side for the sake of clarity of the figure. B Locations of the equivalent current dipoles included in the model are depicted in an MRI of a standard brain in MNI space. ACC, Anterior cingulate cortex; LFEF/RFEF, left and right frontal eye field; LLIP/RLIP, left and right lateral intraparietal area; LPFC/RPFC, left and right prefrontal cortex; LV1/RV1, left and right primary visual cortex.
Table 2.
Coordinates of neuronal sources used in the DCM analysis.
Source coordinates have been taken from *Ford [96] and ΔAichert et al. [94] and were transformed from Talairach to MNI space using the tal2mni tool (http://imaging.mrc-cbu.cam.ac.uk/imaging/MniTalairach).
Table 3.
One principal component for each of the language background factors of interest was extracted from the responses to the corresponding questions in the questionnaire.
Table 4.
Behavioral data for single and mixed task sessions (‘Saccade task’) and for assessing transition effects (‘Transition’).
Error rates (ERR) are given in percentage [%] and saccade latencies (SL) in milliseconds [ms].
Table 5.
Inferential statistics for behavioral data in single and mixed task sessions (‘Saccade task’) and for assessing transition effects (‘Transition’).
Table 6.
Analyses of ERP data for the lateral electrodes.
Table 7.
Analyses of ERP data for the midline electrodes (Fz, Cz, Pz).
Fig 4.
Cue- and target-locked ERPs in the mixed task session on midline and lateral electrodes.
The ERPs are presented with -300 ms at cue onset and 0 ms set at target onset, A for all bilingual and monolingual participants confounded, B for bilingual participants, and C for monolingual participants.
Fig 5.
Cue- and target-locked ERPs in the mixed task session on the three midline electrodes (Fz, Cz, Pz).
The left panel shows the main effect of Saccade task and the right panel the difference waves (antisaccades minus prosaccades) in the two groups. Grey bars mark the time windows used for investigating the cue-locked positivity effect, as well as the target locked N2 and P3 components.
Fig 6.
Target-locked ERPs for the Transition types switch and repetition on midline and lateral electrodes.
The ERPs are presented A for antisaccades, and B for prosaccades, for all bilingual and monolingual participants confounded.
Fig 7.
Target-locked ERPs for the Transition types switch and repetition on the three midline electrodes (Fz, Cz, Pz).
The left panel shows the ERPs for antisaccade trials and the right panel the ERPs for prosaccade trials, confounded over the two groups. The grey bar marks the time window used for investigating the late parietal positivity (LPP) component.
Fig 8.
Saccade-locked ERPs in the mixed task session on midline and lateral electrodes.
The ERPs are presented A for all bilingual and monolingual participants confounded, B for bilingual participants, and C for monolingual participants.
Fig 9.
Saccade-locked ERPs in the mixed task session on the three midline electrodes (Fz, Cz, Pz).
The left panel shows the main effect of Saccade task and the right panel the difference waves (antisaccades minus prosaccades) in the two groups. The grey bar marks the time window used for investigating the presaccadic positivity (PSP) component.
Fig 10.
Cue- and target-locked ERPs in single task blocks on midline and lateral electrodes.
The ERPs are presented with -300 ms at cue onset and 0 ms set at target onset, for all bilingual and monolingual participants confounded.
Fig 11.
Saccade-locked ERPs in single task blocks on midline and lateral electrodes.
The ERPs are presented for all bilingual and monolingual participants confounded.
Table 8.
Pearson correlations between behavioral, ERP and DCM effect sizes on the one hand and language background factors on the other hand, in bilinguals.
Data are presented for mixed task blocks.
Table 9.
Dynamic causal modelling (DCM): modulatory parameter estimates.
Parameter estimates for modulatory connections, i.e. connections that were modelled to vary between the experimental conditions antisaccade vs. prosaccade, are presented for bilingual and monolingual participants.
Fig 12.
A Event-related spectral perturbations (ERSPs) time-locked to target onset are plotted for the Cz electrode for antisaccades and prosaccades and a panel for significant ERSP differences between Saccade tasks is displayed on the right side. B The beta power decrease at around 150 ms after target onset in antisaccades compared to prosaccades over the central and posterior scalp is plotted at frequency 24 Hz. A panel showing the electrodes with a significant ERSP difference between Saccade tasks in red is plotted on the right side.