The perineuronal net (PNN) is a mesh-like proteoglycan structure on the neuronal surface which is involved in regulating plasticity. The PNN regulates plasticity via multiple pathways, one of which is direct regulation of synapses through the control of AMPA receptor mobility. Since neuronal pentraxin 2 (Nptx2) is a known regulator of AMPA receptor mobility and Nptx2 can be removed from the neuronal surface by PNN removal, we investigated whether Nptx2 has a function in the PNN. We found that Nptx2 binds to the glycosaminoglycans hyaluronan and chondroitin sulphate E in the PNN. Furthermore, in primary cortical neuron cultures, the addition of NPTX2 to the culture medium enhances PNN formation during PNN development. These findings suggest Nptx2 as a novel PNN binding protein with a role in the mechanism of PNN formation.

• MeSH
• C-Reactive Protein metabolism   MeSH
• Rats MeSH
• Cells, Cultured MeSH
• Nerve Net chemistry   cytology   metabolism   MeSH
• Neurons chemistry   metabolism   MeSH
• Neuronal Plasticity physiology   MeSH
• Satellite Cells, Perineuronal chemistry   metabolism   MeSH
• Rats, Sprague-Dawley MeSH
• Nerve Tissue Proteins metabolism   MeSH
• Protein Binding physiology   MeSH
• Visual Cortex chemistry   cytology   metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• C-Reactive Protein MeSH
• neuronal pentraxin MeSH Browser
• Nerve Tissue Proteins MeSH

To understand how anatomy and physiology allow an organism to perform its function, it is important to know how information that is transmitted by spikes in the brain is received and encoded. A natural question is whether the spike rate alone encodes the information about a stimulus (rate code), or additional information is contained in the temporal pattern of the spikes (temporal code). Here we address this question using data from the cat Lateral Geniculate Nucleus (LGN), which is the visual portion of the thalamus, through which visual information from the retina is communicated to the visual cortex. We analyzed the responses of LGN neurons to spatially homogeneous spots of various sizes with temporally random luminance modulation. We compared the Firing Rate with the Shannon Information Transmission Rate , which quantifies the information contained in the temporal relationships between spikes. We found that the behavior of these two rates can differ quantitatively. This suggests that the energy used for spiking does not translate directly into the information to be transmitted. We also compared Firing Rates with Information Rates for X-ON and X-OFF cells. We found that, for X-ON cells the Firing Rate and Information Rate often behave in a completely different way, while for X-OFF cells these rates are much more highly correlated. Our results suggest that for X-ON cells a more efficient "temporal code" is employed, while for X-OFF cells a straightforward "rate code" is used, which is more reliable and is correlated with energy consumption.

• Keywords
• Cat LGN, Entropy, Firing rate, Neural coding, ON–OFF cells, Shannon information theory,
• MeSH
• Action Potentials physiology   MeSH
• Mental Processes physiology   MeSH
• Cats MeSH
• Geniculate Bodies cytology   physiology   MeSH
• Neurons physiology   MeSH
• Photic Stimulation methods   MeSH
• Visual Pathways cytology   physiology   MeSH
• Visual Cortex cytology   physiology   MeSH
• Animals MeSH
• Check Tag
• Cats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Comparative Study MeSH

• MeSH
• Time Factors MeSH
• Central Nervous System anatomy & histology   metabolism   physiology   MeSH
• Behavior, Animal MeSH
• Cycloheximide metabolism   MeSH
• Functional Laterality MeSH
• Imprinting, Psychological MeSH
• Cats MeSH
• Rats MeSH
• Chickens MeSH
• Brain Chemistry MeSH
• Mice MeSH
• Animals, Newborn MeSH
• Memory MeSH
• Conditioning, Psychological MeSH
• Nerve Tissue Proteins metabolism   MeSH
• Protein Biosynthesis MeSH
• Puromycin metabolism   MeSH
• RNA biosynthesis   metabolism   MeSH
• Light MeSH
• Darkness MeSH
• Avoidance Learning MeSH
• Learning * MeSH
• Uracil metabolism   MeSH
• Visual Cortex cytology   metabolism   MeSH
• Animals MeSH
• Check Tag
• Cats MeSH
• Rats MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Cycloheximide MeSH
• Nerve Tissue Proteins MeSH
• Puromycin MeSH
• RNA MeSH
• Uracil MeSH