Main statistical effects primarily in the theta (3.57.5 Hz) and alpha (812.5 Hz) range within three positive clusters (in orange), namely in the parietal left (PL), parietal midline (PM), and parietal right (PR) areas (see also Figure 3). These positive clusters suggest separate processes (differences in band power) between handwriting and typewriting mainly in the parietal but also in the central regions. As can be seen in Figure 4, significant clusters of differences in band power were found mainly in parietal and central brain regions.

Network measures Figure 5 shows the adjacency matrix for handwriting in the form of a hub, nodes, and edges of a simplified theoretical network (Figure 5A). Hubs have a higher degree of involvement in the network than nodes as expressed through their functional connectivity values (edges). Figure 5B shows the brain connectivity network results of handwriting compared to typewriting in this experiment. Proposed hubs (in red, 4 departures/arrivals) and nodes (in black, 3 departures/arrivals) interacting between brain regions PL, PM, PR and CL, CM, CR show widespread theta/alpha coherence patterns indicating stronger connectivity when writing as opposed to typing (Figure 5C).

Analyses were run to test for statistical differences in brain activity between handwriting and typewriting. Figure 4 displays the detailed effects (t-tests) of the permutation results. These results showed 32 significant cluster differences between the two experimental conditions. The t-tests revealed significant differences in connectivity General discussion This study investigated brain electrical connectivity as a function of handwriting and typewriting using high-density EEG in young Frontiers in Psychology 05 frontiersin.org

Van der Weel and Van der Meer 10.3389/fpsyg.2023.1219945 FIGURE 4 Symmetric connectivity matrix with t-values (A) and significance Table (B) with significant data clusters in the various sources of interest when handwriting is compared to typewriting in all participants. Thirty-two significant cluster differences marked in orange in (A) and fully described in (B) were found in the matrix and came out particularly significant in the parietal left (PL), parietal midline (PM), and parietal right (PR) areas. FIGURE 5 The adjacency matrix for handwriting. (A) Hub, nodes, and edges of a simplified theoretical network. (B) Brain connectivity network of handwriting compared to typewriting in this experiment. (C) Hubs (in red, 4 departures/arrivals) and nodes (in black, 3 departures/arrivals) interacting between brain regions PL, PM, PR and CL, CM, CR show widespread theta/alpha connectivity patterns when writing by hand, but not when typing.