Differences between the pattern of activation in AO + MI and AO were assessed comparing activity in see more both tasks (dynamic and static balance). Brain activity during
AO + MI was also compared with the brain activity during MI and the contrast between MI and AO was analyzed, too. We also conducted a conjunction analysis (p < .05, FWE corrected) to identify brain areas recruited during both MI and AO + MI of movement. Further, to test whether MI during AO (AO + MI) is simply the sum of brain activity observed during AO and MI, a contrast was calculated for AO + MI versus the summed activity of AO and MI. Finally, we conducted a region of interest (ROI) analysis on M1 (identified according to the Brodmann area 4 of the Talairach Daemon atlas based on the WFU PickAtlas software to generate ROI masks). The ROI was applied as an explicit mask on the model and results were analyzed with a p < .05 FWE corrected statistic for multiple comparison at the voxel level. The activation maps in Fig. 2 illustrate the pattern of activation associated with each experimental condition in comparison with the resting state (for parameter estimates see Fig. 6 in the supplementary material).
Bilateral activity in the SMA, putamen and cerebellum was detected in the MI condition (Fig. 2A). AO + MI also activated the SMA, mTOR inhibitor putamen and cerebellum and there were additional Fossariinae activation foci in ventral premotor cortex (PMv) and dorsal premotor cortex (PMd) (Fig. 2B). Furthermore, the ROI analysis on M1 revealed significant activity on the left side during AO + MI of the dynamic task (p < .001). Interestingly,
no significant activity was detected in the SMA, premotor cortices, M1, basal ganglia or cerebellum during AO ( Fig. 2C). Bilateral activity in the superior temporal gyrus (STG; BA 41, 42), which corresponds to the location of the primary auditory cortex, was detected in all the experimental conditions. In addition, a specific region of the STG, corresponding to BA 22, was consistently activated across conditions. The visual cortex (BA 17, 18, 19) was strongly recruited during AO + MI and AO but not during MI – participants were asked to close their eyes in this condition. The inferior frontal gyrus (BA 44, 45, 46) was activated bilaterally, with left hemisphere dominance, during AO + MI. This region was also active during MI of the balance task (BA 46, left hemisphere only). The insula (BA 13) showed bilateral activation during AO + MI or MI of the dynamic balance task. Activity was detected in the right insula during AO of the dynamic task but at a much weaker intensity than in the AO condition. In order to investigate whether the complexity of the balance task had an influence on activation of brain centers associated with balance control, the dynamic balance task was contrasted with the static balance task.