Learning to learn persistently modifies a neocortical-hippocampal excitatory-inhibitory subcircuit

The neurobiology of psychological concepts like schema, and psychotherapeutic strategies of cognitive behavioral therapy (CBT) is poorly understood, partly because learning to process information confounds, and is rarely distinguished from acquiring content-specific memory. Learning to learn changes one9s overall information-processing ability, whereas neurobiological investigations typically focus on memory for content from particular experiences. We investigated entorhinal cortex-to-dentate gyrus neural circuit changes while mice learn to learn during cognitive control training (CCT) to judiciously use and ignore information. CCT changes synaptic circuit function by persistently modifying an excitatory-inhibitory interneuron subcircuit lasting weeks. CCT increases dentate gyrus expression of PKMζ that maintains long-term potentiation, particularly in somatostatin-expressing inhibitory interneurons that mediate both widespread inhibition, and through disinhibition, also local excitation of dentate gyrus. These findings that CCT modifies excitation-inhibition circuit coordination provide direct neurobiological evidence for a CBT-neuroplasticity hypothesis that, beyond particular item/event associations, learning to learn persistently changes neural circuit function.