New lab paper! Huge effort from @simaggi1 in a wonderful collaboration with @apeyrache using his data.
I call it "Learning to Remember" - of course I'm now going to explain why...
nature.com/articles/s4146…
I call it "Learning to Remember" - of course I'm now going to explain why...
nature.com/articles/s4146…
2/ Rats learned new rules in a Y-maze by trial and error. Unusually, recordings were made in the medial prefrontal cortex from the very first session. So we could ask lots of questions with these data about how PfC's roles in learning and memory intersect 
3/ After each arm choice, the rats had to trudge back to the start again to initiate a new trial. Presumably it would be useful for them to remember what just happened, in order to guide learning of future choices. But how does PfC know what is relevant to remember?
4/ We found on that trudge back that mPfC population activity always represented which arm had been chosen, and whether there was reward or not, right from the very first session.
5/ But... there was also a light-bulb at the end of each arm, and which one was lit was not relevant until the second rule. And lo: the mPfC did not remember this light, until just before the rat realised the light was relevant. It had to learn to remember the light.
6/ If PfC knows previous choice and its outcome, why did rule learning take so long? Because the information was not synchronised. Only just as the rat "got" the rule were the neurons synchronised in the same way on each trudge back to the start: learning to remember together?
7/ To us, one of the most interesting questions raised by this work is: what does mPfC "innately" encode, and what does it have to learn to encode?
