Fig. 1.

Example data for a fTCD word generation task. Upper panel displays the baseline corrected left and right Doppler velocity signals and the lower panel displays the left minus right difference (with standard error bars) as a function of trial time in seconds. Time zero indicates the presentation of the stimulus letter. Baseline and period of interest (poi) intervals are indicated by shaded sections. These data are the averages from 22 adults created using a dopOSCCI output file in Prism (GraphPad Software Inc., La Jolla, CA, USA). Four characteristic peaks are evident in the left and right signals (upper panel). These reflect (1) a generalized task preparation (to a ‘Ready’ signal), (2) a silent word generation at which point the left signal is greater than the right (language processes), (3) verbal report, and (4) the start of relaxation at which point the right signal is greater (potentially reflecting suppression of the verbal material).