Karel Svoboda, lead author of the study, says:
It’s like a game of ping-pong. One excites the other, and the other then excites the first, and so on and so forth. This back and forth maintains these activity patterns that correspond to the memory.
“It was unexpected that these short-term memories are maintained in a thalamocortical loop. “This tells us that these memories are widely distributed across the brain.” (Storing a Memory Involves Distant Parts of the Brain)
The study is here: Maintenance of persistent activity in a frontal thalamocortical loop.
Ninety-eight percent of all sensory input is relayed by the thalamus.