Intel is proposing a new neuromorphic chip design concept that uses multi-input lateral spin valves (LSV) and memristors. Using these two devices in a cross-bar switch lattice, one can build a neuromorphic CPU. The LSVs are the neurons and the memristors are the synapses.
Theoretically such a chip could hold buillions of neurons and synapses and operate in the in the gigahertz or terahertz range. The device will also be quite efficient - about 300 times more efficient than CMOS equivalents.