Individual cells do not encode any memory. Thinking and memory stem from the great variety and combinational complexity of synaptic interlinks between neurons. Certain "circuit" paths are reinforced over time as they are used. The computation itself (thinking, recalling) then is "just" incredibly complex statistics over millions of synapses. And the most awesome thing is that all this happens through chemical reaction chains catalysed by an enormous variety of enzymes and other proteins, and through electrostatic interactions that primarily involve sodium ions!