A semiconductor memory device including a flash memory and a RAM incorporating a pseudo-SRAM contained in an MCP, has an internal transfer control signal for controlling internal data transfer between the flash memory and pseudo-SRAM, and an external transfer control signal for controlling data transfer between an external CPU and pseudo-SRAM, as control signals for the pseudo-SRAM. The network includes a plurality of nodes that collect and transmit data that are ultimately routed to a base station. Methods of screening for pharmaceutically active compounds that enhance myelination, and for genes involved in myelination are also provided.