I don't know about the brain acting like a cache, but synaptic pathway weighting is thought to be modified by how often neurons on either side of it fire near the same time. This is called spike timing dependent plasticity (STDP). The seminal paper for this is: http://www.jneurosci.org/content/18/24/10464.long
It's an analogy for the reinforcing characteristic of neuronal connections, would be perfectly adequate if not for the continuum vs discrete difference in the reinforcement mechanism.
