Fig 1.
Consort diagram showing the recruitment, exclusion and inclusion numbers.
Table 1.
Baseline demographics for young and older adults.
Fig 2.
Illustration of the protocol describing the six visits and the relative time interval between each.
Fig 3.
Schematic illustration of DRAT.
One trial is shown with an array of 4 letters to encode, followed by a 5s delay period, during which participants had to maintain and reorganize the letters into alphabetical order. Examples of the 3 possible responses are shown at the bottom: “New”: the letter was not in the original array; “Valid”: the letter was in the array and the number represented the correct position in the alphabetical order; “Invalid”: the letter was in the array but the number did not match the correct serial position when alphabetized.
Fig 4.
TMS targeting procedure illustrated.
From left to right: Peak BOLD activation (1<z<3) on the left DLPFC associated with increasing set size; E-field grid with 3 × 3 positions and 6 coil orientations centered at the peak BOLD activation; representation of the E-field magnitude for one of the 54 options; correlation matrix between E-field magnitude for each of the 54 options and the activation z-values in which the highest correlation is for position 3 and orientation 4; optimized rTMS coil location (red dot) and orientation (white line).
Table 2.
Summary of mean accuracy and standard error for the significant main effects.
Fig 5.
Mean accuracy in the Invalid trials.
Accuracy for active (black) and sham (grey) rTMS are displayed for each difficulty level. Small lines represent individual data. The longer lines represent the average for each condition.
Table 3.
Summary of mean accuracy and standard error.
Accuracy for Valid and Invalid trials for each active and sham stimulation at each difficulty level (Easy, Medium and Hard) are presented. P-values represent the interaction between Difficulty and Stimulation Type derived from the ANOVA performed for the Invalid condition. Interaction for the Valid condition was not significant and is not shown here.
Table 4.
Summary of mean accuracy and standard error for the significant main effects.
Fig 6.
Mean accuracy in the Invalid trials for active (dark grey) and sham (light grey) rTMS and for each difficulty level, for young (YA) and older adults (OA).
Error bars represent the standard error.
Fig 7.
TMS coil position (spheres) and orientation (arrows) for each subject.
The average coil location is displayed in yellow for the young, and in red for the older group. The spheres represent the coil location and the arrows correspond to the direction of the first phase of the induced E-field pulse (some of the arrowheads are not visible because of the 3D view). The green and the blue sphere represent the average coil location across all subjects, for the young and the old group, respectively.