Primary cilia are required for the persistence of memory and stabilization of perineuronal nets

We investigate the gene expression changes occurring during the transition of aversive episodic memories from recent to remote. Early mechanisms of memory formation (synaptic consolidation) have been extensively characterized. However, delayed mechanisms (systems consolidation), which maintain hippocampal activity as memories stabilize in cortical circuits, are not well understood. Transcriptomic analysis reveals that, contrary to the transient expression of early- and delayed-response genes, the expression of cytoskeleton- and extracellular matrix- associated genes remains dynamic even at remote time points. The most profound expression changes clustered around primary cilium-associated and collagen genes. Overall design: Total RNA extract from the dorsal hippocampus of mice subjected to contextual fear conditioning (3 min context, 2 s electric shock 0.7 mA) 20 min after vehicle or gaboxadol intrahippocampal infusion. Dorsal hippocampi collected 4 or 21 days after conditioning.