We present and experimentally validate two minimal compact memristive models for spiking neuronal signal generation using commercially available low-cost components. The Memristive Integrate-and-Fire (MIF) model for neuronal signaling with two voltage levels: the spike-peak, and the rest-potential. The second model MIF2 promotes local adaptation by accounting for a third refractory voltage level during hyperpolarization. Analytical projections show that a memristive solid-state brain could be realized within (i) the surface area of the median human brain, 2,400cm2, (ii) the same volume of the median human brain, and (iii) a total power budget of approximately 20 W using a 3.5 nm technology.