PT  - JOURNAL ARTICLE
AU  - Silvia Maggi
AU  - Adrien Peyrache
AU  - Mark D. Humphries
TI  - An ensemble code in medial prefrontal cortex links prior events to outcomes during learning
AID  - 10.1101/187948
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 187948
4099  - http://biorxiv.org/content/early/2018/05/03/187948.short
4100  - http://biorxiv.org/content/early/2018/05/03/187948.full
AB  - The prefrontal cortex is implicated in learning the rules of an environment through trial and error. But it is unclear how such learning is related to the prefrontal cortex’s role in short-term memory. Here we ask if the encoding of short-term memory in prefrontal cortex is used by rats learning decision rules in a Y-maze task. We find that a similar pattern of neural ensemble activity is selectively recalled after reinforcement for a correct decision. This reinforcement-selective recall only reliably occurs immediately before the abrupt behavioural transitions indicating successful learning of the current rule, and fades quickly thereafter. We could simultaneously decode multiple, retrospective task events from the ensemble activity, suggesting the recalled ensemble activity has multiplexed encoding of prior events. Our results suggest that successful trial-and-error learning is dependent on reinforcement tagging the relevant features of the environment to maintain in prefrontal cortex short-term memory.