The first line of research is aimed at determining the factors that play a role in establishing orderly maps of the peripheral receptor surface within the somatosensory cortex. Experiments suggest that the formation of such maps involves two different sets of interactions between groups of neurons. The first are intrinsic interactions between groups of neurons at different levels of the neuro axis. These interactions play a role in the formation of broad topographic relations. The second are extrinsic in that they are ultimately derived from the periphery and can be passed along by the neural axis to the somatosensory cortex.
Extrinsic factors refine topographic organization into a detailed somatotopic map.
The second line of research is aimed at the cortical projection neurons. These neurons interconnect a given cortical area with both other cortical areas and other parts of the central nervous system. During the course of development, classes of these neurons undergo major changes in their distribution pattern. For example, early in development, one major class of cortical projection neurons sends one neuronal process to the other hemisphere and a second to a region within the same hemisphere. In the adult, a given neuron projects to only one of these targets.