Perineuronal Nets in the Adult Sensory Cortex Are Necessary for Fear Learning.
Banerjee SB1, Gutzeit VA2, Baman J2, Aoued HS3, Doshi NK2, Liu RC4, Ressler KJ5.
structures known as perineuronal nets (PNNs) are key components of the
extracellular matrix (ECM). Once fully crystallized by adulthood, they are
largely stable throughout life. Contrary to previous reports that PNNs
inhibit processes involving plasticity, here we report that the dynamic
regulation of PNN expression in the adult auditory cortex is vital for fear learning and consolidation in response to pure
tones. Specifically, after first confirming the necessity of auditory cortical
activity for fear learning and consolidation, we observed that mRNA
levels of key proteoglycan components of PNNs were enhanced 4 hr
after fear conditioning but were no
longer different from the control groups 24 hr later. A similar pattern of
regulation was observed in numbers of cells surrounded by PNNs and area
occupied by them in the auditory cortex.
Finally, the removal of auditory cortex PNNs
resulted in a deficit in fear learning and consolidation.