(A) top: location of the secondary somatosensory cortex (SII) projected onto the surface of a post-mortem squirrel monkey brain. bottom: modular organizations of touch and heat nociceptive neurons clusters in the S2 sub-region of SII cortex. (B) Schematic illustration of the topographic map of cortical areas around the sub-regions (PV, S2, and VS) of the secondary somatosensory cortex (SII) and its surrounding cortical areas of 3a, 3b, 1, and 2 of the first somatosensory cortex (SI), area 7b (7b), retro-insula (Ri), posterior insula, located at the caudal end of lateral sulcus. Green and red circles indicate the locations of touch and heat nociceptive neuron modules identified by electrophysiology in the current study. Light orange circles represent the fine-scale heat nociception network identified in the operculum region in a previous fMRI study [6].