Figure 7.

Mean hemodynamic responses in the right hemisphere of infants, collapsed across event, for each of the two agent types: (a) human hand and (b) mechanical hand. T4 and T6 correspond to the International 10–20 coordinates, and T4 served as our right hemisphere anchor point when securing the headgear on the infant. The red curves indicate change in oxyhemoglobin concentration (HbO), the blue curves indicate change in de-oxyhemoglobin concentration (HbR), and the green curves indicate the sum total of HbO and HbR (HbT). The black vertical lines indicate time points 0 s and 15 s, the onset and offset of the trial, respectively. The horizontal axis indicates time (−2 s to 25 s), and the vertical axis indicates change in optical density units (ΔOD, in µM cm). The numbers to the right of each waveform indicate the channel (see Figure 4b for reference). The highlighted channels indicate the four spatially contiguous channels (see text) that were averaged to obtain a right region of interest (ROI). The response obtained in the right ROI differed significantly for (a) and (b).