Figure 1:
Flow chart demonstrating pre-processing steps in SPM12 and the customized MATLAB program for processing fMRI data. Our dual-task paradigm consisted of 30 s (N=15 data points) blocks for rest, counting (cognitive task), flexion (motor task), and counting + flexion (dual-task) conditions. Two trials resulted in two whole time series (N = number of data points, 180 data points each, for a time (t) of 260 second (s)), which underwent complexity analysis. Cog 1: counting down by ones; and Cog 2: counting down by threes; CN: cognitively normal; MCI: mild cognitive impairment; SMP: statistical parametric mapping; DICOM: digital imaging and communications in medicine; NIfTI: neuroimaging informatics technology initiative; MNI: Montreal Neurological Institute; SampEn: sample entropy; MSE: multiscale entropy; Hz: Hertz