Fig 1.
Timeline of task administration and design details of each task.
Fig 2.
Modeled stimulation electric field.
Electrode placement locations (anode in red and cathode in blue) and the output of finite element modeling of the estimated electric field for the Anodal stimulation condition. Arrows denote the direction of the current from anode to cathode.
Table 1.
Example stimulus sentences for each condition.
Fig 3.
Garden-path comprehension accuracy.
Average comprehension accuracy to questions following garden-path sentences for each stimulation group and task condition. Error bars = ±1 standard error of the mean.
Table 2.
Estimate coefficients from generalized linear mixed-effects models for garden-path accuracy on the reading task.
Fig 4.
Average uncorrected reading times on the garden-path sentence conditions in the region of interest (Note: the content of this region varied for sentence type, such that it was “sparkled brightly” in ambiguous sentences and “hid” in unambiguous sentences). Reading times are plotted for correct items only for each stimulation group and task condition. Error bars = ±1 standard error of the mean.
Table 3.
Estimate coefficients from linear mixed-effects models for reading times in the critical area of garden-path sentences.
Fig 5.
Relative clause reading times.
Average uncorrected reading times on the relative clause sentence conditions in the region of interest (Note: the content of this region varied for sentence type, such that it was “who the expert questioned” in object-extract sentences and “who questioned the expert” in subject-extracted sentences). Reading times are plotted for correct items only for each stimulation group and task condition. Error bars = ±1 standard error of the mean.
Table 4.
Estimate coefficients from linear mixed-effects models for length-corrected reading times in the critical region of relative clauses.
Fig 6.
Average n-back discriminability (A′) for each stimulation group and task condition. A′ is a non-parametric signal detection index of how well participants can discriminate targets from non-targets; thus a higher A′ value corresponds to better discriminability. Error bars = ±1 standard error of the mean.
Table 5.
Estimate coefficients from linear mixed-effects models for n-back discriminability (A′).
Fig 7.
Average n-back response criterion (Grier’s B′′) for each stimulation group and task condition. Grier’s B′′ is a non-parametric signal detection index of participants’ bias to respond ‘target or ‘non-target.’ A higher Grier’s B′′ value corresponds to a conservative bias to say ‘non-target,’ while a lower Grier’s B′′ indexes a higher likelihood of judging an item to be a ‘target.’ Error bars = ±1 standard error of the mean.
Table 6.
Estimate coefficients from linear mixed-effects models for n-back response criterion (Grier’s B′′).
Fig 8.
Interactions of Conflict Level and Difficulty Level with Stimulation in the N-Back and Reading Tasks. Note that the relative clause items have a no Conflict Level effects to evaluate. Colors indicate cases when the Stimulation contrasts significantly predicted performance. Gray shading = no effects for any contrast; Red shading = Anodal > Sham; Blue shading = Anodal > Cathodal; Purple shading = Anodal outperforms remaining groups; Green shading = Anodal and Sham outperform Cathodal.