title: N-acetylgalactosamine positive perineuronal nets in the saccade-related-part of the cerebellar fastigial nucleus do not maintain saccade gain.
abstract: Perineuronal nets (PNNs) accumulate around neurons near the end of developmental critical periods. PNNs are structures of the extracellular matrix which surround synaptic contacts and contain chondroitin sulfate proteoglycans. Previous studies suggest that the chondroitin sulfate chains of PNNs inhibit synaptic plasticity and thereby help end critical periods. PNNs surround a high proportion of neurons in the cerebellar nuclei. These PNNs form during approximately the same time that movements achieve normal accuracy. It is possible that PNNs in the cerebellar nuclei inhibit plasticity to maintain the synaptic organization that produces those accurate movements. We tested whether or not PNNs in a saccade-related part of the cerebellar nuclei maintain accurate saccade size by digesting a part of them in an adult monkey performing a task that changes saccade size (long term saccade adaptation). We use the enzyme Chondroitinase ABC to digest the glycosaminoglycan side chains of proteoglycans present in the majority of PNNs. We show that this manipulation does not result in faster, larger, or more persistent adaptation. Our result indicates that intact perineuronal nets around saccade-related neurons in the cerebellar nuclei are not important for maintaining long-term saccade gain.
authors.affiliation: Department of Biological Structure, University of Washington, Seattle, Washington, United States of America.
authors.forename: Adrienne
authors.initials: A
authors.lastname: Mueller
authors.affiliation: Department of Biological Structure, University of Washington, Seattle, Washington, United States of America.
authors.forename: Adam
authors.initials: A
authors.lastname: Davis
authors.affiliation: Department of Physiology and Biophysics, University of Washington, Seattle, Washington, United States of America.
authors.forename: Steven S
authors.initials: SS
authors.lastname: Carlson
authors.affiliation: Department of Biological Structure, University of Washington, Seattle, Washington, United States of America.
authors.forename: Farrel R
authors.initials: FR
authors.lastname: Robinson
mesh_terms: D000116:Acetylgalactosamine / Q000378:metabolism*; D000221:Adaptation, Ocular / Q000502:physiology; D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D002529:Cerebellar Nuclei / Q000502:physiology*; D019765:Chondroitin ABC Lyase / Q000378:metabolism; D011508:Chondroitin Sulfate Proteoglycans / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism / Q000502:physiology; D008253:Macaca mulatta; D008297:Male; D009415:Nerve Net / Q000378:metabolism / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D012438:Saccades / Q000502:physiology*; D013997:Time Factors
chemical_list: D011508:Chondroitin Sulfate Proteoglycans; D019765:Chondroitin ABC Lyase; D000116:Acetylgalactosamine