Fig. 1.

Here we show the probe design and placement for DOI measurements. This probe consisted of eight detector positions (most medial and lateral rows) and four source positions (middle row). The source-detector separation was 2.9 cm. This probe was positioned approximately over the subject's contralateral primary motor cortex as the subject lay in the MRI scanner. The probe also contains vitamin E rings placed on the caps of the optodes, which allowed registration of the optode array in the MR structural image.