Reproducible activation in BA2, 1 and 3b associated with texture discrimination in healthy volunteers over time

We aimed to quantify specific location and reproducibility of brain activation associated with discrimination of a moving textured surface in adult healthy volunteers over a 6-month interval. A sensory stimulation device was developed to provide a texture stimulus to the fingertips at a controlled speed and pressure. Repeat measurements of regional cerebral blood flow, using positron emission tomography (PET), were obtained in 10 healthy individuals, aged 33 to 80 years (mean = 55.8 years), at scanning sessions separated by 6 months. Stimulation and rest conditions were presented to either the right, dominant (n = 5) or left non-dominant (n = 5) hand. Activation location was objectively quantified with reference to probabilistic cytoarchitectonic maps. Differences in activation over time and regions of common activation were also quantified. Participants consistently activated Brodmann areas (BA) 2, 3b and 1, somatosensory areas of postcentral gyrus, at initial and 6-month studies: 93.1% of common activation for the right-hand (RH) and 60.6% for left-hand (LH) stimulation group were in these areas. Reproducible activation in BA6, 4a and 4p was also observed for the RH group (6.8% of common activation) and LH group (39.4%). There were no sites of significant difference over time for either hand. Highly consistent location of activation over time suggests that changes in loci of activation may be confidently monitored in adults using this paradigm. Use of probabilistic cytoarchitectonic maps permitted objective quantification of the anatomical location of the core of reproducible activation.