Touching on somatosensory specializations in mammals

Specialized species often reveal general principles of brain organization and provide systems for analysis of sensory function. Subterranean species dependent on touch have particularly large somatosensory areas with modular cortical representations of sensory surfaces. Some species have added cortical areas to processing networks, have developed tactile foveas and have superior colliculi primarily devoted to somatosensation rather than vision. Recent studies reveal surprisingly large cortical representations of oral structures in primates and mole-rats. Cortical modules represent a range of different sensory surfaces in rodents, star-nosed moles and primates, indicating that similar developmental mechanisms operate in diverse species. Finally, manipulation of patterning genes in mice suggests evolutionary mechanisms for producing the specialized corticies of subterranean species.