The theta-gamma code in predictive processing and mnemonic updating.

Predictive processing has become a leading theory about how the brain works. Yet, it remains an open question, how predictive processes are realized in the brain. Here I discuss theta-gamma coupling as one potential neural mechanism for prediction and model updating. Building on Lisman and colleagues SOCRATIC model, theta-gamma coupling has been associated with phase precession and learning phenomena in medio-temporal lobe of rodents, where it completes and retains a sequence of places or items (i.e., predictive models), which may be updated upon prediction errors (i.e., model updating), as signaled by dopaminergic inputs from prefrontal networks. This framework, spanning the molecular to the network level, matches excitingly well with recent findings on predictive processing, mnemonic updating, and perceptual foraging for the theta-gamma code in human cognition. In sum, I use the case of theta-gamma coupling, to link the predictive processing account, a very general concept of how the brain works, to specific neural processes which may implement predictive processing and model updating at the cognitive, network, cellular and molecular level.