Perineuronal Nets in the Adult Sensory Cortex Are Necessary for Fear Learning

• Authors: Sunayana B. Banerjee, Emory University; Vanessa A. Gutzeit, Emory University; Justin Baman, Emory University; Hadj S. Aoued, Emory University; Nandini K. Doshi, Emory University; Robert C Liu, Emory University; Kerry Ressler, Emory University
• Journal Title: Neuron
• Volume: Volume 95, Number 1
• Publisher: Elsevier (Cell Press) | 2017-07-05, Pages 169-179.e3
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.neuron.2017.06.007
• Subjects: Biology, Neuroscience; Biology, General
• Keywords: Chondroitinase ABC; PTSD; auditory cortex; conditioning; consolidation; extracellular matrix; hearing; memory; perceptual learning; plasticity; Animals; Auditory Cortex; Conditioning (Psychology); Extracellular Matrix; Fear; GABA-A Receptor Agonists; Learning; Memory Consolidation; Mice; Muscimol; Proteoglycans; RNA, Messenger

Abstract

Lattice-like 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. Banerjee et al., 2017 show that key components of the extracellular matrix, perineuronal nets (PNNs) in the auditory cortex of adult mice, are necessary for consolidation of fear learning in response to Pavlovian fear conditioning.