Anatomy

Neuroscience

Biology

Perineuronal net

Glycosaminoglycan

Extracellular matrix

Composite material

Chondroitin sulfate proteoglycan

Materials science

Extracellular

Proteoglycan

Chondroitin sulfate

Soma

Cell biology

Neuroplasticity

Plasticity

Nature reviews. Neuroscience

Perineuronal nets (PNNs) are extracellular matrix (ECM) chondroitin sulfate proteoglycan (CSPG)-containing structures that surround the soma and dendrites of various mammalian neuronal cell types. PNNs appear during development around the time that the critical periods for developmental plasticity end and are important for both their onset and closure. A similar structure — the perinodal ECM — surrounds the axonal nodes of Ranvier and appears as myelination is completed, acting as an ion-diffusion barrier that affects axonal conduction speed. Recent work has revealed the importance of PNNs in controlling plasticity in the CNS. Digestion, blocking or removal of PNNs influences functional recovery after a variety of CNS lesions. PNNs have further been shown to be involved in the regulation of memory and have been implicated in a number of psychiatric disorders. Specialized extracellular matrix structures known as perineuronal nets surround the soma and dendrites of many CNS neurons. Fawcett and colleagues provide an update on our current understanding of perineuronal net composition, formation and functional roles in brain function and disease.

The roles of perineuronal nets and the perinodal extracellular matrix in neuronal function