Depletion of Perineuronal Nets Enhances Recognition Memory and Long-Term Depression in the Perirhinal Cortex

Aging somatosensory cortex displays increased density of WFA-binding perineuronal nets associated with GAD-negative neurons

“…Their fast-spiking behavior, electrical coupling and soma targeting endow them with abilities to detect synchrony and also promote synchronous oscillations in excitatory neurons (Deans et al, 2001;Freund, 2003;Hensch, 2005). Disruption of PNNs reduces perisomatic inhibition and destabilizes the excitatory-inhibitory balance, thus enabling rewiring of synaptic connections and the recurrence of plasticity (Bukalo et al, 2001;Saghatelyan et al, 2001;Sale et al, 2007;Romberg et al, 2013). The increased numbers of PNNs observed in aging may potentially be responsible for the opposite phenomenon -stabilization of an existing, well performing network of neuronal connections, especially those of inhibitory provenience.…”

Modifications of perineuronal nets and remodelling of excitatory and inhibitory afferents during vestibular compensation in the adult mouse

“…PNNs are formed at the end of developmental critical periods for experience-dependent plasticity and contribute to the stabilisation of specific connection patterns (Dityatev et al 2010;Geissler et al 2013). Pharmacological degradation of PNNs in the adult CNS restores juvenile levels of plasticity, improves functional recovery after damage and enhances cognitive functions (Pizzorusso et al 2002(Pizzorusso et al , 2006Galtrey et al 2007;Gogolla et al 2009;Romberg et al 2013;Happel et al 2014;Yang et al 2014;Gherardini et al 2015). Mutant mice with vestigial PNNs (due to the lack of cartilage link protein-1) show persistent plasticity into adulthood and enhanced memory Romberg et al 2013).…”

Semaphorin 3A Binds to the Perineuronal Nets via Chondroitin Sulfate Type E Motifs in Rodent Brains

“…Degradation of CS by enzymatic treatment using chondroitinase ABC (ChABC) has demonstrated remarkable enhancement in plasticity in the visual cortex (8) and in the injured CNS (11)(12)(13) and prolongation of memory (14). The same enhancement of plasticity and memory is also observed in animals that lack Crtl1 in the CNS and therefore have attenuated PNNs, indicating that ChABC promotes plasticity through digestion of CS-GAGs in PNNs (9).…”