Figure 2. The patchy functional organization of heat nociception in the lateral sulcus region and temperature-dependent fMRI responses in SII cortex.

(A & B) Probability maps of fMRI responses to 47.5°C heat stimulation on two coronal images (4 mm apart, and thresholded at 4/10 runs) from one representative monkey. Color scale indicates the probability of activation across runs. Left inserts are schematic illustrations of the cortical areas and interareal borders identified by cytoarchitectural features of the brain tissue in the squirrel monkey. The inserts are adapted and modified from Burton and Jones [4] and Jones and Burton [31]. (C & D) Percentage (color symbols) and two-gamma fitted (color lines) BOLD fMRI time courses to stimulation of the digits with four different temperatures (D) and in four representative areas (C). The orange bar indicates the stimulus duration of 30 sec. BOLD signal amplitude at each time point is presented as the mean ± standard deviation (SD). (E) Exponential fit of the fMRI response peaks to each temperature. fMRI data from eleven hemispheres (out of nine monkeys) are quantified. P1-P4: patches 1-4. AP2 & AP6: slices 2 and 6 in the anterior to posterior direction. These two slices are 4 mm apart. S2: secondary somatosensory cortex. 7b: area 7b. Ri: retro-insula. pIns: posterior insula.