| Abstract: | This study mapped the mechanosensory projections to cerebral cortex of sheep, to complete earlier partial maps and to relate cortical projections to the organization previously determined in ventrobasal thalamus. Tungsten microelectrodes were used to explore thoroughly the walls and depths of cortical sulci as well as the previously studied gyral crowns, for regions responsive to mechanical stimulation of peripheral receptors, in sheep anesthetized with Dialurethane or nitrous oxide with either halothane or methoxyflurane. Earlier findings of a large projection from the ipsilateral mouth, lips and nose were confirmed. In addition, a small representation of the contralateral body and limbs was found which corresponds in most respects to the “second” sensory area (SII) of other mammals. In the primary (SI) sensory cortex, representations of the body and limbs were not found despite thorough fine-grain mapping. Responses possibly representing a vestige of primary sensory cortex, and mechanosensory responses in claustro-cortex, were also observed. |
